Eric Lee / smarc-fsl-linux-kernel

trace_events_hist.c 142 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412 4413 4414 4415 4416 4417 4418 4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442 4443 4444 4445 4446 4447 4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521 4522 4523 4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747 4748 4749 4750 4751 4752 4753 4754 4755 4756 4757 4758 4759 4760 4761 4762 4763 4764 4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827 4828 4829 4830 4831 4832 4833 4834 4835 4836 4837 4838 4839 4840 4841 4842 4843 4844 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868 4869 4870 4871 4872 4873 4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891 4892 4893 4894 4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953 4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002 5003 5004 5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032 5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131 5132 5133 5134 5135 5136 5137 5138 5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159 5160 5161 5162 5163 5164 5165 5166 5167 5168 5169 5170 5171 5172 5173 5174 5175 5176 5177 5178 5179 5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193 5194 5195 5196 5197 5198 5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209 5210 5211 5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222 5223 5224 5225 5226 5227 5228 5229 5230 5231 5232 5233 5234 5235 5236 5237 5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257 5258 5259 5260 5261 5262 5263 5264 5265 5266 5267 5268 5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291 5292 5293 5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332 5333 5334 5335 5336 5337 5338 5339 5340 5341 5342 5343 5344 5345 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358 5359 5360 5361 5362 5363 5364 5365 5366 5367 5368 5369 5370 5371 5372 5373 5374 5375 5376 5377 5378 5379 5380 5381 5382 5383 5384 5385 5386 5387 5388 5389 5390 5391 5392 5393 5394 5395 5396 5397 5398 5399 5400 5401 5402 5403 5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422 5423 5424 5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449 5450 5451 5452 5453 5454 5455 5456 5457 5458 5459 5460 5461 5462 5463 5464 5465 5466 5467 5468 5469 5470 5471 5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482 5483 5484 5485 5486 5487 5488 5489 5490 5491 5492 5493 5494 5495 5496 5497 5498 5499 5500 5501 5502 5503 5504 5505 5506 5507 5508 5509 5510 5511 5512 5513 5514 5515 5516 5517 5518 5519 5520 5521 5522 5523 5524 5525 5526 5527 5528 5529 5530 5531 5532 5533 5534 5535 5536 5537 5538 5539 5540 5541 5542 5543 5544 5545 5546 5547 5548 5549 5550 5551 5552 5553 5554 5555 5556 5557 5558 5559 5560 5561 5562 5563 5564 5565 5566 5567 5568 5569 5570 5571 5572 5573 5574 5575 5576 5577 5578 5579 5580 5581 5582 5583 5584 5585 5586 5587 5588 5589 5590 5591 5592 5593 5594 5595 5596 5597 5598 5599 5600 5601 5602 5603 5604 5605 5606 5607 5608 5609 5610 5611 5612 5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623 5624 5625 5626 5627 5628 5629 5630 5631 5632 5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657 5658 5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671 5672 5673 5674 5675 5676 5677 5678 5679 5680 5681 5682 5683 5684 5685 5686 5687 5688 5689 5690 5691 5692 5693 5694 5695 5696 5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707 5708 5709 5710 5711 5712 5713 5714 5715 5716 5717 5718 5719 5720 5721 5722 5723 5724 5725 5726 5727 5728 5729 5730 5731 5732 5733 5734 5735 5736 5737 5738 5739 5740 5741 5742 5743 5744 5745 5746 5747 5748 5749 5750 5751 5752 5753 5754 5755 5756 5757 5758 5759 5760 5761 5762 5763 5764 5765 5766 5767 5768 5769 5770 5771 5772 5773 5774 5775 5776 5777 5778 5779 5780 5781 5782 5783 5784 5785 5786 5787 5788 5789 5790 5791 5792 5793 5794 5795 5796 5797 5798 5799 5800 5801 5802 5803 5804 5805 5806 5807 5808 5809 5810 5811 5812 5813 5814 5815 5816 5817 5818 5819 5820 5821 5822 5823 5824 5825 5826 5827 5828 5829 5830 5831 5832 5833 5834 5835 5836 5837 5838 5839 5840 5841 5842 5843 5844 5845 5846 5847 5848 5849 5850 5851 5852 5853 5854 5855 5856 5857 5858 5859 5860 5861 5862 5863 5864 5865 5866 5867 5868 5869 5870 5871 5872 5873 5874 5875 5876 5877 5878 5879 5880 5881 5882 5883 5884 5885 5886 5887 5888 5889 5890 5891 5892 5893 5894 5895 5896 5897 5898 5899 5900 5901 5902 5903 5904 5905 5906 5907 5908 5909 5910 5911 5912 5913 5914 5915 5916 5917 5918 5919 5920 5921 5922 5923 5924 5925 5926 5927 5928 5929 5930 5931 5932 5933 5934 5935 5936 5937 5938 5939 5940 5941 5942 5943 5944 5945 5946 
// SPDX-License-Identifier: GPL-2.0
/*
 * trace_events_hist - trace event hist triggers
 *
 * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
 */

#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/security.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <linux/rculist.h>
#include <linux/tracefs.h>

/* for gfp flag names */
#include <linux/trace_events.h>
#include <trace/events/mmflags.h>

#include "tracing_map.h"
#include "trace_synth.h"

#define ERRORS								\
	C(NONE,			"No error"),				\
	C(DUPLICATE_VAR,	"Variable already defined"),		\
	C(VAR_NOT_UNIQUE,	"Variable name not unique, need to use fully qualified name (subsys.event.var) for variable"), \
	C(TOO_MANY_VARS,	"Too many variables defined"),		\
	C(MALFORMED_ASSIGNMENT,	"Malformed assignment"),		\
	C(NAMED_MISMATCH,	"Named hist trigger doesn't match existing named trigger (includes variables)"), \
	C(TRIGGER_EEXIST,	"Hist trigger already exists"),		\
	C(TRIGGER_ENOENT_CLEAR,	"Can't clear or continue a nonexistent hist trigger"), \
	C(SET_CLOCK_FAIL,	"Couldn't set trace_clock"),		\
	C(BAD_FIELD_MODIFIER,	"Invalid field modifier"),		\
	C(TOO_MANY_SUBEXPR,	"Too many subexpressions (3 max)"),	\
	C(TIMESTAMP_MISMATCH,	"Timestamp units in expression don't match"), \
	C(TOO_MANY_FIELD_VARS,	"Too many field variables defined"),	\
	C(EVENT_FILE_NOT_FOUND,	"Event file not found"),		\
	C(HIST_NOT_FOUND,	"Matching event histogram not found"),	\
	C(HIST_CREATE_FAIL,	"Couldn't create histogram for field"),	\
	C(SYNTH_VAR_NOT_FOUND,	"Couldn't find synthetic variable"),	\
	C(SYNTH_EVENT_NOT_FOUND,"Couldn't find synthetic event"),	\
	C(SYNTH_TYPE_MISMATCH,	"Param type doesn't match synthetic event field type"), \
	C(SYNTH_COUNT_MISMATCH,	"Param count doesn't match synthetic event field count"), \
	C(FIELD_VAR_PARSE_FAIL,	"Couldn't parse field variable"),	\
	C(VAR_CREATE_FIND_FAIL,	"Couldn't create or find variable"),	\
	C(ONX_NOT_VAR,		"For onmax(x) or onchange(x), x must be a variable"), \
	C(ONX_VAR_NOT_FOUND,	"Couldn't find onmax or onchange variable"), \
	C(ONX_VAR_CREATE_FAIL,	"Couldn't create onmax or onchange variable"), \
	C(FIELD_VAR_CREATE_FAIL,"Couldn't create field variable"),	\
	C(TOO_MANY_PARAMS,	"Too many action params"),		\
	C(PARAM_NOT_FOUND,	"Couldn't find param"),			\
	C(INVALID_PARAM,	"Invalid action param"),		\
	C(ACTION_NOT_FOUND,	"No action found"),			\
	C(NO_SAVE_PARAMS,	"No params found for save()"),		\
	C(TOO_MANY_SAVE_ACTIONS,"Can't have more than one save() action per hist"), \
	C(ACTION_MISMATCH,	"Handler doesn't support action"),	\
	C(NO_CLOSING_PAREN,	"No closing paren found"),		\
	C(SUBSYS_NOT_FOUND,	"Missing subsystem"),			\
	C(INVALID_SUBSYS_EVENT,	"Invalid subsystem or event name"),	\
	C(INVALID_REF_KEY,	"Using variable references in keys not supported"), \
	C(VAR_NOT_FOUND,	"Couldn't find variable"),		\
	C(FIELD_NOT_FOUND,	"Couldn't find field"),			\
	C(EMPTY_ASSIGNMENT,	"Empty assignment"),			\
	C(INVALID_SORT_MODIFIER,"Invalid sort modifier"),		\
	C(EMPTY_SORT_FIELD,	"Empty sort field"),			\
	C(TOO_MANY_SORT_FIELDS,	"Too many sort fields (Max = 2)"),	\
	C(INVALID_SORT_FIELD,	"Sort field must be a key or a val"),

#undef C
#define C(a, b)		HIST_ERR_##a

enum { ERRORS };

#undef C
#define C(a, b)		b

static const char *err_text[] = { ERRORS };

struct hist_field;

typedef u64 (*hist_field_fn_t) (struct hist_field *field,
				struct tracing_map_elt *elt,
				struct ring_buffer_event *rbe,
				void *event);

#define HIST_FIELD_OPERANDS_MAX	2
#define HIST_FIELDS_MAX		(TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
#define HIST_ACTIONS_MAX	8

enum field_op_id {
	FIELD_OP_NONE,
	FIELD_OP_PLUS,
	FIELD_OP_MINUS,
	FIELD_OP_UNARY_MINUS,
};

/*
 * A hist_var (histogram variable) contains variable information for
 * hist_fields having the HIST_FIELD_FL_VAR or HIST_FIELD_FL_VAR_REF
 * flag set.  A hist_var has a variable name e.g. ts0, and is
 * associated with a given histogram trigger, as specified by
 * hist_data.  The hist_var idx is the unique index assigned to the
 * variable by the hist trigger's tracing_map.  The idx is what is
 * used to set a variable's value and, by a variable reference, to
 * retrieve it.
 */
struct hist_var {
	char				*name;
	struct hist_trigger_data	*hist_data;
	unsigned int			idx;
};

struct hist_field {
	struct ftrace_event_field	*field;
	unsigned long			flags;
	hist_field_fn_t			fn;
	unsigned int			ref;
	unsigned int			size;
	unsigned int			offset;
	unsigned int                    is_signed;
	const char			*type;
	struct hist_field		*operands[HIST_FIELD_OPERANDS_MAX];
	struct hist_trigger_data	*hist_data;

	/*
	 * Variable fields contain variable-specific info in var.
	 */
	struct hist_var			var;
	enum field_op_id		operator;
	char				*system;
	char				*event_name;

	/*
	 * The name field is used for EXPR and VAR_REF fields.  VAR
	 * fields contain the variable name in var.name.
	 */
	char				*name;

	/*
	 * When a histogram trigger is hit, if it has any references
	 * to variables, the values of those variables are collected
	 * into a var_ref_vals array by resolve_var_refs().  The
	 * current value of each variable is read from the tracing_map
	 * using the hist field's hist_var.idx and entered into the
	 * var_ref_idx entry i.e. var_ref_vals[var_ref_idx].
	 */
	unsigned int			var_ref_idx;
	bool                            read_once;

	unsigned int			var_str_idx;
};

static u64 hist_field_none(struct hist_field *field,
			   struct tracing_map_elt *elt,
			   struct ring_buffer_event *rbe,
			   void *event)
{
	return 0;
}

static u64 hist_field_counter(struct hist_field *field,
			      struct tracing_map_elt *elt,
			      struct ring_buffer_event *rbe,
			      void *event)
{
	return 1;
}

static u64 hist_field_string(struct hist_field *hist_field,
			     struct tracing_map_elt *elt,
			     struct ring_buffer_event *rbe,
			     void *event)
{
	char *addr = (char *)(event + hist_field->field->offset);

	return (u64)(unsigned long)addr;
}

static u64 hist_field_dynstring(struct hist_field *hist_field,
				struct tracing_map_elt *elt,
				struct ring_buffer_event *rbe,
				void *event)
{
	u32 str_item = *(u32 *)(event + hist_field->field->offset);
	int str_loc = str_item & 0xffff;
	char *addr = (char *)(event + str_loc);

	return (u64)(unsigned long)addr;
}

static u64 hist_field_pstring(struct hist_field *hist_field,
			      struct tracing_map_elt *elt,
			      struct ring_buffer_event *rbe,
			      void *event)
{
	char **addr = (char **)(event + hist_field->field->offset);

	return (u64)(unsigned long)*addr;
}

static u64 hist_field_log2(struct hist_field *hist_field,
			   struct tracing_map_elt *elt,
			   struct ring_buffer_event *rbe,
			   void *event)
{
	struct hist_field *operand = hist_field->operands[0];

	u64 val = operand->fn(operand, elt, rbe, event);

	return (u64) ilog2(roundup_pow_of_two(val));
}

static u64 hist_field_plus(struct hist_field *hist_field,
			   struct tracing_map_elt *elt,
			   struct ring_buffer_event *rbe,
			   void *event)
{
	struct hist_field *operand1 = hist_field->operands[0];
	struct hist_field *operand2 = hist_field->operands[1];

	u64 val1 = operand1->fn(operand1, elt, rbe, event);
	u64 val2 = operand2->fn(operand2, elt, rbe, event);

	return val1 + val2;
}

static u64 hist_field_minus(struct hist_field *hist_field,
			    struct tracing_map_elt *elt,
			    struct ring_buffer_event *rbe,
			    void *event)
{
	struct hist_field *operand1 = hist_field->operands[0];
	struct hist_field *operand2 = hist_field->operands[1];

	u64 val1 = operand1->fn(operand1, elt, rbe, event);
	u64 val2 = operand2->fn(operand2, elt, rbe, event);

	return val1 - val2;
}

static u64 hist_field_unary_minus(struct hist_field *hist_field,
				  struct tracing_map_elt *elt,
				  struct ring_buffer_event *rbe,
				  void *event)
{
	struct hist_field *operand = hist_field->operands[0];

	s64 sval = (s64)operand->fn(operand, elt, rbe, event);
	u64 val = (u64)-sval;

	return val;
}

#define DEFINE_HIST_FIELD_FN(type)					\
	static u64 hist_field_##type(struct hist_field *hist_field,	\
				     struct tracing_map_elt *elt,	\
				     struct ring_buffer_event *rbe,	\
				     void *event)			\
{									\
	type *addr = (type *)(event + hist_field->field->offset);	\
									\
	return (u64)(unsigned long)*addr;				\
}

DEFINE_HIST_FIELD_FN(s64);
DEFINE_HIST_FIELD_FN(u64);
DEFINE_HIST_FIELD_FN(s32);
DEFINE_HIST_FIELD_FN(u32);
DEFINE_HIST_FIELD_FN(s16);
DEFINE_HIST_FIELD_FN(u16);
DEFINE_HIST_FIELD_FN(s8);
DEFINE_HIST_FIELD_FN(u8);

#define for_each_hist_field(i, hist_data)	\
	for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)

#define for_each_hist_val_field(i, hist_data)	\
	for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)

#define for_each_hist_key_field(i, hist_data)	\
	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)

#define HIST_STACKTRACE_DEPTH	16
#define HIST_STACKTRACE_SIZE	(HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
#define HIST_STACKTRACE_SKIP	5

#define HITCOUNT_IDX		0
#define HIST_KEY_SIZE_MAX	(MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)

enum hist_field_flags {
	HIST_FIELD_FL_HITCOUNT		= 1 << 0,
	HIST_FIELD_FL_KEY		= 1 << 1,
	HIST_FIELD_FL_STRING		= 1 << 2,
	HIST_FIELD_FL_HEX		= 1 << 3,
	HIST_FIELD_FL_SYM		= 1 << 4,
	HIST_FIELD_FL_SYM_OFFSET	= 1 << 5,
	HIST_FIELD_FL_EXECNAME		= 1 << 6,
	HIST_FIELD_FL_SYSCALL		= 1 << 7,
	HIST_FIELD_FL_STACKTRACE	= 1 << 8,
	HIST_FIELD_FL_LOG2		= 1 << 9,
	HIST_FIELD_FL_TIMESTAMP		= 1 << 10,
	HIST_FIELD_FL_TIMESTAMP_USECS	= 1 << 11,
	HIST_FIELD_FL_VAR		= 1 << 12,
	HIST_FIELD_FL_EXPR		= 1 << 13,
	HIST_FIELD_FL_VAR_REF		= 1 << 14,
	HIST_FIELD_FL_CPU		= 1 << 15,
	HIST_FIELD_FL_ALIAS		= 1 << 16,
};

struct var_defs {
	unsigned int	n_vars;
	char		*name[TRACING_MAP_VARS_MAX];
	char		*expr[TRACING_MAP_VARS_MAX];
};

struct hist_trigger_attrs {
	char		*keys_str;
	char		*vals_str;
	char		*sort_key_str;
	char		*name;
	char		*clock;
	bool		pause;
	bool		cont;
	bool		clear;
	bool		ts_in_usecs;
	unsigned int	map_bits;

	char		*assignment_str[TRACING_MAP_VARS_MAX];
	unsigned int	n_assignments;

	char		*action_str[HIST_ACTIONS_MAX];
	unsigned int	n_actions;

	struct var_defs	var_defs;
};

struct field_var {
	struct hist_field	*var;
	struct hist_field	*val;
};

struct field_var_hist {
	struct hist_trigger_data	*hist_data;
	char				*cmd;
};

struct hist_trigger_data {
	struct hist_field               *fields[HIST_FIELDS_MAX];
	unsigned int			n_vals;
	unsigned int			n_keys;
	unsigned int			n_fields;
	unsigned int			n_vars;
	unsigned int			n_var_str;
	unsigned int			key_size;
	struct tracing_map_sort_key	sort_keys[TRACING_MAP_SORT_KEYS_MAX];
	unsigned int			n_sort_keys;
	struct trace_event_file		*event_file;
	struct hist_trigger_attrs	*attrs;
	struct tracing_map		*map;
	bool				enable_timestamps;
	bool				remove;
	struct hist_field               *var_refs[TRACING_MAP_VARS_MAX];
	unsigned int			n_var_refs;

	struct action_data		*actions[HIST_ACTIONS_MAX];
	unsigned int			n_actions;

	struct field_var		*field_vars[SYNTH_FIELDS_MAX];
	unsigned int			n_field_vars;
	unsigned int			n_field_var_str;
	struct field_var_hist		*field_var_hists[SYNTH_FIELDS_MAX];
	unsigned int			n_field_var_hists;

	struct field_var		*save_vars[SYNTH_FIELDS_MAX];
	unsigned int			n_save_vars;
	unsigned int			n_save_var_str;
};

struct action_data;

typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
			     struct tracing_map_elt *elt, void *rec,
			     struct ring_buffer_event *rbe, void *key,
			     struct action_data *data, u64 *var_ref_vals);

typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);

enum handler_id {
	HANDLER_ONMATCH = 1,
	HANDLER_ONMAX,
	HANDLER_ONCHANGE,
};

enum action_id {
	ACTION_SAVE = 1,
	ACTION_TRACE,
	ACTION_SNAPSHOT,
};

struct action_data {
	enum handler_id		handler;
	enum action_id		action;
	char			*action_name;
	action_fn_t		fn;

	unsigned int		n_params;
	char			*params[SYNTH_FIELDS_MAX];

	/*
	 * When a histogram trigger is hit, the values of any
	 * references to variables, including variables being passed
	 * as parameters to synthetic events, are collected into a
	 * var_ref_vals array.  This var_ref_idx array is an array of
	 * indices into the var_ref_vals array, one for each synthetic
	 * event param, and is passed to the synthetic event
	 * invocation.
	 */
	unsigned int		var_ref_idx[TRACING_MAP_VARS_MAX];
	struct synth_event	*synth_event;
	bool			use_trace_keyword;
	char			*synth_event_name;

	union {
		struct {
			char			*event;
			char			*event_system;
		} match_data;

		struct {
			/*
			 * var_str contains the $-unstripped variable
			 * name referenced by var_ref, and used when
			 * printing the action.  Because var_ref
			 * creation is deferred to create_actions(),
			 * we need a per-action way to save it until
			 * then, thus var_str.
			 */
			char			*var_str;

			/*
			 * var_ref refers to the variable being
			 * tracked e.g onmax($var).
			 */
			struct hist_field	*var_ref;

			/*
			 * track_var contains the 'invisible' tracking
			 * variable created to keep the current
			 * e.g. max value.
			 */
			struct hist_field	*track_var;

			check_track_val_fn_t	check_val;
			action_fn_t		save_data;
		} track_data;
	};
};

struct track_data {
	u64				track_val;
	bool				updated;

	unsigned int			key_len;
	void				*key;
	struct tracing_map_elt		elt;

	struct action_data		*action_data;
	struct hist_trigger_data	*hist_data;
};

struct hist_elt_data {
	char *comm;
	u64 *var_ref_vals;
	char *field_var_str[SYNTH_FIELDS_MAX];
};

struct snapshot_context {
	struct tracing_map_elt	*elt;
	void			*key;
};

static void track_data_free(struct track_data *track_data)
{
	struct hist_elt_data *elt_data;

	if (!track_data)
		return;

	kfree(track_data->key);

	elt_data = track_data->elt.private_data;
	if (elt_data) {
		kfree(elt_data->comm);
		kfree(elt_data);
	}

	kfree(track_data);
}

static struct track_data *track_data_alloc(unsigned int key_len,
					   struct action_data *action_data,
					   struct hist_trigger_data *hist_data)
{
	struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
	struct hist_elt_data *elt_data;

	if (!data)
		return ERR_PTR(-ENOMEM);

	data->key = kzalloc(key_len, GFP_KERNEL);
	if (!data->key) {
		track_data_free(data);
		return ERR_PTR(-ENOMEM);
	}

	data->key_len = key_len;
	data->action_data = action_data;
	data->hist_data = hist_data;

	elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
	if (!elt_data) {
		track_data_free(data);
		return ERR_PTR(-ENOMEM);
	}

	data->elt.private_data = elt_data;

	elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL);
	if (!elt_data->comm) {
		track_data_free(data);
		return ERR_PTR(-ENOMEM);
	}

	return data;
}

static char last_cmd[MAX_FILTER_STR_VAL];
static char last_cmd_loc[MAX_FILTER_STR_VAL];

static int errpos(char *str)
{
	return err_pos(last_cmd, str);
}

static void last_cmd_set(struct trace_event_file *file, char *str)
{
	const char *system = NULL, *name = NULL;
	struct trace_event_call *call;

	if (!str)
		return;

	strcpy(last_cmd, "hist:");
	strncat(last_cmd, str, MAX_FILTER_STR_VAL - 1 - sizeof("hist:"));

	if (file) {
		call = file->event_call;
		system = call->class->system;
		if (system) {
			name = trace_event_name(call);
			if (!name)
				system = NULL;
		}
	}

	if (system)
		snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, "hist:%s:%s", system, name);
}

static void hist_err(struct trace_array *tr, u8 err_type, u8 err_pos)
{
	tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,
			err_type, err_pos);
}

static void hist_err_clear(void)
{
	last_cmd[0] = '\0';
	last_cmd_loc[0] = '\0';
}

typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals,
				    unsigned int *var_ref_idx);

static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
			       unsigned int *var_ref_idx)
{
	struct tracepoint *tp = event->tp;

	if (unlikely(atomic_read(&tp->key.enabled) > 0)) {
		struct tracepoint_func *probe_func_ptr;
		synth_probe_func_t probe_func;
		void *__data;

		if (!(cpu_online(raw_smp_processor_id())))
			return;

		probe_func_ptr = rcu_dereference_sched((tp)->funcs);
		if (probe_func_ptr) {
			do {
				probe_func = probe_func_ptr->func;
				__data = probe_func_ptr->data;
				probe_func(__data, var_ref_vals, var_ref_idx);
			} while ((++probe_func_ptr)->func);
		}
	}
}

static void action_trace(struct hist_trigger_data *hist_data,
			 struct tracing_map_elt *elt, void *rec,
			 struct ring_buffer_event *rbe, void *key,
			 struct action_data *data, u64 *var_ref_vals)
{
	struct synth_event *event = data->synth_event;

	trace_synth(event, var_ref_vals, data->var_ref_idx);
}

struct hist_var_data {
	struct list_head list;
	struct hist_trigger_data *hist_data;
};

static u64 hist_field_timestamp(struct hist_field *hist_field,
				struct tracing_map_elt *elt,
				struct ring_buffer_event *rbe,
				void *event)
{
	struct hist_trigger_data *hist_data = hist_field->hist_data;
	struct trace_array *tr = hist_data->event_file->tr;

	u64 ts = ring_buffer_event_time_stamp(rbe);

	if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
		ts = ns2usecs(ts);

	return ts;
}

static u64 hist_field_cpu(struct hist_field *hist_field,
			  struct tracing_map_elt *elt,
			  struct ring_buffer_event *rbe,
			  void *event)
{
	int cpu = smp_processor_id();

	return cpu;
}

/**
 * check_field_for_var_ref - Check if a VAR_REF field references a variable
 * @hist_field: The VAR_REF field to check
 * @var_data: The hist trigger that owns the variable
 * @var_idx: The trigger variable identifier
 *
 * Check the given VAR_REF field to see whether or not it references
 * the given variable associated with the given trigger.
 *
 * Return: The VAR_REF field if it does reference the variable, NULL if not
 */
static struct hist_field *
check_field_for_var_ref(struct hist_field *hist_field,
			struct hist_trigger_data *var_data,
			unsigned int var_idx)
{
	WARN_ON(!(hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF));

	if (hist_field && hist_field->var.idx == var_idx &&
	    hist_field->var.hist_data == var_data)
		return hist_field;

	return NULL;
}

/**
 * find_var_ref - Check if a trigger has a reference to a trigger variable
 * @hist_data: The hist trigger that might have a reference to the variable
 * @var_data: The hist trigger that owns the variable
 * @var_idx: The trigger variable identifier
 *
 * Check the list of var_refs[] on the first hist trigger to see
 * whether any of them are references to the variable on the second
 * trigger.
 *
 * Return: The VAR_REF field referencing the variable if so, NULL if not
 */
static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
				       struct hist_trigger_data *var_data,
				       unsigned int var_idx)
{
	struct hist_field *hist_field;
	unsigned int i;

	for (i = 0; i < hist_data->n_var_refs; i++) {
		hist_field = hist_data->var_refs[i];
		if (check_field_for_var_ref(hist_field, var_data, var_idx))
			return hist_field;
	}

	return NULL;
}

/**
 * find_any_var_ref - Check if there is a reference to a given trigger variable
 * @hist_data: The hist trigger
 * @var_idx: The trigger variable identifier
 *
 * Check to see whether the given variable is currently referenced by
 * any other trigger.
 *
 * The trigger the variable is defined on is explicitly excluded - the
 * assumption being that a self-reference doesn't prevent a trigger
 * from being removed.
 *
 * Return: The VAR_REF field referencing the variable if so, NULL if not
 */
static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
					   unsigned int var_idx)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_field *found = NULL;
	struct hist_var_data *var_data;

	list_for_each_entry(var_data, &tr->hist_vars, list) {
		if (var_data->hist_data == hist_data)
			continue;
		found = find_var_ref(var_data->hist_data, hist_data, var_idx);
		if (found)
			break;
	}

	return found;
}

/**
 * check_var_refs - Check if there is a reference to any of trigger's variables
 * @hist_data: The hist trigger
 *
 * A trigger can define one or more variables.  If any one of them is
 * currently referenced by any other trigger, this function will
 * determine that.

 * Typically used to determine whether or not a trigger can be removed
 * - if there are any references to a trigger's variables, it cannot.
 *
 * Return: True if there is a reference to any of trigger's variables
 */
static bool check_var_refs(struct hist_trigger_data *hist_data)
{
	struct hist_field *field;
	bool found = false;
	int i;

	for_each_hist_field(i, hist_data) {
		field = hist_data->fields[i];
		if (field && field->flags & HIST_FIELD_FL_VAR) {
			if (find_any_var_ref(hist_data, field->var.idx)) {
				found = true;
				break;
			}
		}
	}

	return found;
}

static struct hist_var_data *find_hist_vars(struct hist_trigger_data *hist_data)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_var_data *var_data, *found = NULL;

	list_for_each_entry(var_data, &tr->hist_vars, list) {
		if (var_data->hist_data == hist_data) {
			found = var_data;
			break;
		}
	}

	return found;
}

static bool field_has_hist_vars(struct hist_field *hist_field,
				unsigned int level)
{
	int i;

	if (level > 3)
		return false;

	if (!hist_field)
		return false;

	if (hist_field->flags & HIST_FIELD_FL_VAR ||
	    hist_field->flags & HIST_FIELD_FL_VAR_REF)
		return true;

	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) {
		struct hist_field *operand;

		operand = hist_field->operands[i];
		if (field_has_hist_vars(operand, level + 1))
			return true;
	}

	return false;
}

static bool has_hist_vars(struct hist_trigger_data *hist_data)
{
	struct hist_field *hist_field;
	int i;

	for_each_hist_field(i, hist_data) {
		hist_field = hist_data->fields[i];
		if (field_has_hist_vars(hist_field, 0))
			return true;
	}

	return false;
}

static int save_hist_vars(struct hist_trigger_data *hist_data)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_var_data *var_data;

	var_data = find_hist_vars(hist_data);
	if (var_data)
		return 0;

	if (tracing_check_open_get_tr(tr))
		return -ENODEV;

	var_data = kzalloc(sizeof(*var_data), GFP_KERNEL);
	if (!var_data) {
		trace_array_put(tr);
		return -ENOMEM;
	}

	var_data->hist_data = hist_data;
	list_add(&var_data->list, &tr->hist_vars);

	return 0;
}

static void remove_hist_vars(struct hist_trigger_data *hist_data)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_var_data *var_data;

	var_data = find_hist_vars(hist_data);
	if (!var_data)
		return;

	if (WARN_ON(check_var_refs(hist_data)))
		return;

	list_del(&var_data->list);

	kfree(var_data);

	trace_array_put(tr);
}

static struct hist_field *find_var_field(struct hist_trigger_data *hist_data,
					 const char *var_name)
{
	struct hist_field *hist_field, *found = NULL;
	int i;

	for_each_hist_field(i, hist_data) {
		hist_field = hist_data->fields[i];
		if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR &&
		    strcmp(hist_field->var.name, var_name) == 0) {
			found = hist_field;
			break;
		}
	}

	return found;
}

static struct hist_field *find_var(struct hist_trigger_data *hist_data,
				   struct trace_event_file *file,
				   const char *var_name)
{
	struct hist_trigger_data *test_data;
	struct event_trigger_data *test;
	struct hist_field *hist_field;

	lockdep_assert_held(&event_mutex);

	hist_field = find_var_field(hist_data, var_name);
	if (hist_field)
		return hist_field;

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			test_data = test->private_data;
			hist_field = find_var_field(test_data, var_name);
			if (hist_field)
				return hist_field;
		}
	}

	return NULL;
}

static struct trace_event_file *find_var_file(struct trace_array *tr,
					      char *system,
					      char *event_name,
					      char *var_name)
{
	struct hist_trigger_data *var_hist_data;
	struct hist_var_data *var_data;
	struct trace_event_file *file, *found = NULL;

	if (system)
		return find_event_file(tr, system, event_name);

	list_for_each_entry(var_data, &tr->hist_vars, list) {
		var_hist_data = var_data->hist_data;
		file = var_hist_data->event_file;
		if (file == found)
			continue;

		if (find_var_field(var_hist_data, var_name)) {
			if (found) {
				hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE, errpos(var_name));
				return NULL;
			}

			found = file;
		}
	}

	return found;
}

static struct hist_field *find_file_var(struct trace_event_file *file,
					const char *var_name)
{
	struct hist_trigger_data *test_data;
	struct event_trigger_data *test;
	struct hist_field *hist_field;

	lockdep_assert_held(&event_mutex);

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			test_data = test->private_data;
			hist_field = find_var_field(test_data, var_name);
			if (hist_field)
				return hist_field;
		}
	}

	return NULL;
}

static struct hist_field *
find_match_var(struct hist_trigger_data *hist_data, char *var_name)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_field *hist_field, *found = NULL;
	struct trace_event_file *file;
	unsigned int i;

	for (i = 0; i < hist_data->n_actions; i++) {
		struct action_data *data = hist_data->actions[i];

		if (data->handler == HANDLER_ONMATCH) {
			char *system = data->match_data.event_system;
			char *event_name = data->match_data.event;

			file = find_var_file(tr, system, event_name, var_name);
			if (!file)
				continue;
			hist_field = find_file_var(file, var_name);
			if (hist_field) {
				if (found) {
					hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE,
						 errpos(var_name));
					return ERR_PTR(-EINVAL);
				}

				found = hist_field;
			}
		}
	}
	return found;
}

static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
					 char *system,
					 char *event_name,
					 char *var_name)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_field *hist_field = NULL;
	struct trace_event_file *file;

	if (!system || !event_name) {
		hist_field = find_match_var(hist_data, var_name);
		if (IS_ERR(hist_field))
			return NULL;
		if (hist_field)
			return hist_field;
	}

	file = find_var_file(tr, system, event_name, var_name);
	if (!file)
		return NULL;

	hist_field = find_file_var(file, var_name);

	return hist_field;
}

static u64 hist_field_var_ref(struct hist_field *hist_field,
			      struct tracing_map_elt *elt,
			      struct ring_buffer_event *rbe,
			      void *event)
{
	struct hist_elt_data *elt_data;
	u64 var_val = 0;

	if (WARN_ON_ONCE(!elt))
		return var_val;

	elt_data = elt->private_data;
	var_val = elt_data->var_ref_vals[hist_field->var_ref_idx];

	return var_val;
}

static bool resolve_var_refs(struct hist_trigger_data *hist_data, void *key,
			     u64 *var_ref_vals, bool self)
{
	struct hist_trigger_data *var_data;
	struct tracing_map_elt *var_elt;
	struct hist_field *hist_field;
	unsigned int i, var_idx;
	bool resolved = true;
	u64 var_val = 0;

	for (i = 0; i < hist_data->n_var_refs; i++) {
		hist_field = hist_data->var_refs[i];
		var_idx = hist_field->var.idx;
		var_data = hist_field->var.hist_data;

		if (var_data == NULL) {
			resolved = false;
			break;
		}

		if ((self && var_data != hist_data) ||
		    (!self && var_data == hist_data))
			continue;

		var_elt = tracing_map_lookup(var_data->map, key);
		if (!var_elt) {
			resolved = false;
			break;
		}

		if (!tracing_map_var_set(var_elt, var_idx)) {
			resolved = false;
			break;
		}

		if (self || !hist_field->read_once)
			var_val = tracing_map_read_var(var_elt, var_idx);
		else
			var_val = tracing_map_read_var_once(var_elt, var_idx);

		var_ref_vals[i] = var_val;
	}

	return resolved;
}

static const char *hist_field_name(struct hist_field *field,
				   unsigned int level)
{
	const char *field_name = "";

	if (level > 1)
		return field_name;

	if (field->field)
		field_name = field->field->name;
	else if (field->flags & HIST_FIELD_FL_LOG2 ||
		 field->flags & HIST_FIELD_FL_ALIAS)
		field_name = hist_field_name(field->operands[0], ++level);
	else if (field->flags & HIST_FIELD_FL_CPU)
		field_name = "cpu";
	else if (field->flags & HIST_FIELD_FL_EXPR ||
		 field->flags & HIST_FIELD_FL_VAR_REF) {
		if (field->system) {
			static char full_name[MAX_FILTER_STR_VAL];

			strcat(full_name, field->system);
			strcat(full_name, ".");
			strcat(full_name, field->event_name);
			strcat(full_name, ".");
			strcat(full_name, field->name);
			field_name = full_name;
		} else
			field_name = field->name;
	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
		field_name = "common_timestamp";

	if (field_name == NULL)
		field_name = "";

	return field_name;
}

static hist_field_fn_t select_value_fn(int field_size, int field_is_signed)
{
	hist_field_fn_t fn = NULL;

	switch (field_size) {
	case 8:
		if (field_is_signed)
			fn = hist_field_s64;
		else
			fn = hist_field_u64;
		break;
	case 4:
		if (field_is_signed)
			fn = hist_field_s32;
		else
			fn = hist_field_u32;
		break;
	case 2:
		if (field_is_signed)
			fn = hist_field_s16;
		else
			fn = hist_field_u16;
		break;
	case 1:
		if (field_is_signed)
			fn = hist_field_s8;
		else
			fn = hist_field_u8;
		break;
	}

	return fn;
}

static int parse_map_size(char *str)
{
	unsigned long size, map_bits;
	int ret;

	ret = kstrtoul(str, 0, &size);
	if (ret)
		goto out;

	map_bits = ilog2(roundup_pow_of_two(size));
	if (map_bits < TRACING_MAP_BITS_MIN ||
	    map_bits > TRACING_MAP_BITS_MAX)
		ret = -EINVAL;
	else
		ret = map_bits;
 out:
	return ret;
}

static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
{
	unsigned int i;

	if (!attrs)
		return;

	for (i = 0; i < attrs->n_assignments; i++)
		kfree(attrs->assignment_str[i]);

	for (i = 0; i < attrs->n_actions; i++)
		kfree(attrs->action_str[i]);

	kfree(attrs->name);
	kfree(attrs->sort_key_str);
	kfree(attrs->keys_str);
	kfree(attrs->vals_str);
	kfree(attrs->clock);
	kfree(attrs);
}

static int parse_action(char *str, struct hist_trigger_attrs *attrs)
{
	int ret = -EINVAL;

	if (attrs->n_actions >= HIST_ACTIONS_MAX)
		return ret;

	if ((str_has_prefix(str, "onmatch(")) ||
	    (str_has_prefix(str, "onmax(")) ||
	    (str_has_prefix(str, "onchange("))) {
		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
		if (!attrs->action_str[attrs->n_actions]) {
			ret = -ENOMEM;
			return ret;
		}
		attrs->n_actions++;
		ret = 0;
	}
	return ret;
}

static int parse_assignment(struct trace_array *tr,
			    char *str, struct hist_trigger_attrs *attrs)
{
	int len, ret = 0;

	if ((len = str_has_prefix(str, "key=")) ||
	    (len = str_has_prefix(str, "keys="))) {
		attrs->keys_str = kstrdup(str + len, GFP_KERNEL);
		if (!attrs->keys_str) {
			ret = -ENOMEM;
			goto out;
		}
	} else if ((len = str_has_prefix(str, "val=")) ||
		   (len = str_has_prefix(str, "vals=")) ||
		   (len = str_has_prefix(str, "values="))) {
		attrs->vals_str = kstrdup(str + len, GFP_KERNEL);
		if (!attrs->vals_str) {
			ret = -ENOMEM;
			goto out;
		}
	} else if ((len = str_has_prefix(str, "sort="))) {
		attrs->sort_key_str = kstrdup(str + len, GFP_KERNEL);
		if (!attrs->sort_key_str) {
			ret = -ENOMEM;
			goto out;
		}
	} else if (str_has_prefix(str, "name=")) {
		attrs->name = kstrdup(str, GFP_KERNEL);
		if (!attrs->name) {
			ret = -ENOMEM;
			goto out;
		}
	} else if ((len = str_has_prefix(str, "clock="))) {
		str += len;

		str = strstrip(str);
		attrs->clock = kstrdup(str, GFP_KERNEL);
		if (!attrs->clock) {
			ret = -ENOMEM;
			goto out;
		}
	} else if ((len = str_has_prefix(str, "size="))) {
		int map_bits = parse_map_size(str + len);

		if (map_bits < 0) {
			ret = map_bits;
			goto out;
		}
		attrs->map_bits = map_bits;
	} else {
		char *assignment;

		if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
			hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(str));
			ret = -EINVAL;
			goto out;
		}

		assignment = kstrdup(str, GFP_KERNEL);
		if (!assignment) {
			ret = -ENOMEM;
			goto out;
		}

		attrs->assignment_str[attrs->n_assignments++] = assignment;
	}
 out:
	return ret;
}

static struct hist_trigger_attrs *
parse_hist_trigger_attrs(struct trace_array *tr, char *trigger_str)
{
	struct hist_trigger_attrs *attrs;
	int ret = 0;

	attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
	if (!attrs)
		return ERR_PTR(-ENOMEM);

	while (trigger_str) {
		char *str = strsep(&trigger_str, ":");
		char *rhs;

		rhs = strchr(str, '=');
		if (rhs) {
			if (!strlen(++rhs)) {
				ret = -EINVAL;
				hist_err(tr, HIST_ERR_EMPTY_ASSIGNMENT, errpos(str));
				goto free;
			}
			ret = parse_assignment(tr, str, attrs);
			if (ret)
				goto free;
		} else if (strcmp(str, "pause") == 0)
			attrs->pause = true;
		else if ((strcmp(str, "cont") == 0) ||
			 (strcmp(str, "continue") == 0))
			attrs->cont = true;
		else if (strcmp(str, "clear") == 0)
			attrs->clear = true;
		else {
			ret = parse_action(str, attrs);
			if (ret)
				goto free;
		}
	}

	if (!attrs->keys_str) {
		ret = -EINVAL;
		goto free;
	}

	if (!attrs->clock) {
		attrs->clock = kstrdup("global", GFP_KERNEL);
		if (!attrs->clock) {
			ret = -ENOMEM;
			goto free;
		}
	}

	return attrs;
 free:
	destroy_hist_trigger_attrs(attrs);

	return ERR_PTR(ret);
}

static inline void save_comm(char *comm, struct task_struct *task)
{
	if (!task->pid) {
		strcpy(comm, "<idle>");
		return;
	}

	if (WARN_ON_ONCE(task->pid < 0)) {
		strcpy(comm, "<XXX>");
		return;
	}

	strncpy(comm, task->comm, TASK_COMM_LEN);
}

static void hist_elt_data_free(struct hist_elt_data *elt_data)
{
	unsigned int i;

	for (i = 0; i < SYNTH_FIELDS_MAX; i++)
		kfree(elt_data->field_var_str[i]);

	kfree(elt_data->comm);
	kfree(elt_data);
}

static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
{
	struct hist_elt_data *elt_data = elt->private_data;

	hist_elt_data_free(elt_data);
}

static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
{
	struct hist_trigger_data *hist_data = elt->map->private_data;
	unsigned int size = TASK_COMM_LEN;
	struct hist_elt_data *elt_data;
	struct hist_field *key_field;
	unsigned int i, n_str;

	elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
	if (!elt_data)
		return -ENOMEM;

	for_each_hist_key_field(i, hist_data) {
		key_field = hist_data->fields[i];

		if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
			elt_data->comm = kzalloc(size, GFP_KERNEL);
			if (!elt_data->comm) {
				kfree(elt_data);
				return -ENOMEM;
			}
			break;
		}
	}

	n_str = hist_data->n_field_var_str + hist_data->n_save_var_str +
		hist_data->n_var_str;
	if (n_str > SYNTH_FIELDS_MAX) {
		hist_elt_data_free(elt_data);
		return -EINVAL;
	}

	BUILD_BUG_ON(STR_VAR_LEN_MAX & (sizeof(u64) - 1));

	size = STR_VAR_LEN_MAX;

	for (i = 0; i < n_str; i++) {
		elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
		if (!elt_data->field_var_str[i]) {
			hist_elt_data_free(elt_data);
			return -ENOMEM;
		}
	}

	elt->private_data = elt_data;

	return 0;
}

static void hist_trigger_elt_data_init(struct tracing_map_elt *elt)
{
	struct hist_elt_data *elt_data = elt->private_data;

	if (elt_data->comm)
		save_comm(elt_data->comm, current);
}

static const struct tracing_map_ops hist_trigger_elt_data_ops = {
	.elt_alloc	= hist_trigger_elt_data_alloc,
	.elt_free	= hist_trigger_elt_data_free,
	.elt_init	= hist_trigger_elt_data_init,
};

static const char *get_hist_field_flags(struct hist_field *hist_field)
{
	const char *flags_str = NULL;

	if (hist_field->flags & HIST_FIELD_FL_HEX)
		flags_str = "hex";
	else if (hist_field->flags & HIST_FIELD_FL_SYM)
		flags_str = "sym";
	else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
		flags_str = "sym-offset";
	else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
		flags_str = "execname";
	else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
		flags_str = "syscall";
	else if (hist_field->flags & HIST_FIELD_FL_LOG2)
		flags_str = "log2";
	else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS)
		flags_str = "usecs";

	return flags_str;
}

static void expr_field_str(struct hist_field *field, char *expr)
{
	if (field->flags & HIST_FIELD_FL_VAR_REF)
		strcat(expr, "$");

	strcat(expr, hist_field_name(field, 0));

	if (field->flags && !(field->flags & HIST_FIELD_FL_VAR_REF)) {
		const char *flags_str = get_hist_field_flags(field);

		if (flags_str) {
			strcat(expr, ".");
			strcat(expr, flags_str);
		}
	}
}

static char *expr_str(struct hist_field *field, unsigned int level)
{
	char *expr;

	if (level > 1)
		return NULL;

	expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
	if (!expr)
		return NULL;

	if (!field->operands[0]) {
		expr_field_str(field, expr);
		return expr;
	}

	if (field->operator == FIELD_OP_UNARY_MINUS) {
		char *subexpr;

		strcat(expr, "-(");
		subexpr = expr_str(field->operands[0], ++level);
		if (!subexpr) {
			kfree(expr);
			return NULL;
		}
		strcat(expr, subexpr);
		strcat(expr, ")");

		kfree(subexpr);

		return expr;
	}

	expr_field_str(field->operands[0], expr);

	switch (field->operator) {
	case FIELD_OP_MINUS:
		strcat(expr, "-");
		break;
	case FIELD_OP_PLUS:
		strcat(expr, "+");
		break;
	default:
		kfree(expr);
		return NULL;
	}

	expr_field_str(field->operands[1], expr);

	return expr;
}

static int contains_operator(char *str)
{
	enum field_op_id field_op = FIELD_OP_NONE;
	char *op;

	op = strpbrk(str, "+-");
	if (!op)
		return FIELD_OP_NONE;

	switch (*op) {
	case '-':
		if (*str == '-')
			field_op = FIELD_OP_UNARY_MINUS;
		else
			field_op = FIELD_OP_MINUS;
		break;
	case '+':
		field_op = FIELD_OP_PLUS;
		break;
	default:
		break;
	}

	return field_op;
}

static void get_hist_field(struct hist_field *hist_field)
{
	hist_field->ref++;
}

static void __destroy_hist_field(struct hist_field *hist_field)
{
	if (--hist_field->ref > 1)
		return;

	kfree(hist_field->var.name);
	kfree(hist_field->name);
	kfree(hist_field->type);

	kfree(hist_field->system);
	kfree(hist_field->event_name);

	kfree(hist_field);
}

static void destroy_hist_field(struct hist_field *hist_field,
			       unsigned int level)
{
	unsigned int i;

	if (level > 3)
		return;

	if (!hist_field)
		return;

	if (hist_field->flags & HIST_FIELD_FL_VAR_REF)
		return; /* var refs will be destroyed separately */

	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
		destroy_hist_field(hist_field->operands[i], level + 1);

	__destroy_hist_field(hist_field);
}

static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
					    struct ftrace_event_field *field,
					    unsigned long flags,
					    char *var_name)
{
	struct hist_field *hist_field;

	if (field && is_function_field(field))
		return NULL;

	hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
	if (!hist_field)
		return NULL;

	hist_field->ref = 1;

	hist_field->hist_data = hist_data;

	if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
		goto out; /* caller will populate */

	if (flags & HIST_FIELD_FL_VAR_REF) {
		hist_field->fn = hist_field_var_ref;
		goto out;
	}

	if (flags & HIST_FIELD_FL_HITCOUNT) {
		hist_field->fn = hist_field_counter;
		hist_field->size = sizeof(u64);
		hist_field->type = kstrdup("u64", GFP_KERNEL);
		if (!hist_field->type)
			goto free;
		goto out;
	}

	if (flags & HIST_FIELD_FL_STACKTRACE) {
		hist_field->fn = hist_field_none;
		goto out;
	}

	if (flags & HIST_FIELD_FL_LOG2) {
		unsigned long fl = flags & ~HIST_FIELD_FL_LOG2;
		hist_field->fn = hist_field_log2;
		hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
		hist_field->size = hist_field->operands[0]->size;
		hist_field->type = kstrdup(hist_field->operands[0]->type, GFP_KERNEL);
		if (!hist_field->type)
			goto free;
		goto out;
	}

	if (flags & HIST_FIELD_FL_TIMESTAMP) {
		hist_field->fn = hist_field_timestamp;
		hist_field->size = sizeof(u64);
		hist_field->type = kstrdup("u64", GFP_KERNEL);
		if (!hist_field->type)
			goto free;
		goto out;
	}

	if (flags & HIST_FIELD_FL_CPU) {
		hist_field->fn = hist_field_cpu;
		hist_field->size = sizeof(int);
		hist_field->type = kstrdup("unsigned int", GFP_KERNEL);
		if (!hist_field->type)
			goto free;
		goto out;
	}

	if (WARN_ON_ONCE(!field))
		goto out;

	if (is_string_field(field)) {
		flags |= HIST_FIELD_FL_STRING;

		hist_field->size = MAX_FILTER_STR_VAL;
		hist_field->type = kstrdup(field->type, GFP_KERNEL);
		if (!hist_field->type)
			goto free;

		if (field->filter_type == FILTER_STATIC_STRING)
			hist_field->fn = hist_field_string;
		else if (field->filter_type == FILTER_DYN_STRING)
			hist_field->fn = hist_field_dynstring;
		else
			hist_field->fn = hist_field_pstring;
	} else {
		hist_field->size = field->size;
		hist_field->is_signed = field->is_signed;
		hist_field->type = kstrdup(field->type, GFP_KERNEL);
		if (!hist_field->type)
			goto free;

		hist_field->fn = select_value_fn(field->size,
						 field->is_signed);
		if (!hist_field->fn) {
			destroy_hist_field(hist_field, 0);
			return NULL;
		}
	}
 out:
	hist_field->field = field;
	hist_field->flags = flags;

	if (var_name) {
		hist_field->var.name = kstrdup(var_name, GFP_KERNEL);
		if (!hist_field->var.name)
			goto free;
	}

	return hist_field;
 free:
	destroy_hist_field(hist_field, 0);
	return NULL;
}

static void destroy_hist_fields(struct hist_trigger_data *hist_data)
{
	unsigned int i;

	for (i = 0; i < HIST_FIELDS_MAX; i++) {
		if (hist_data->fields[i]) {
			destroy_hist_field(hist_data->fields[i], 0);
			hist_data->fields[i] = NULL;
		}
	}

	for (i = 0; i < hist_data->n_var_refs; i++) {
		WARN_ON(!(hist_data->var_refs[i]->flags & HIST_FIELD_FL_VAR_REF));
		__destroy_hist_field(hist_data->var_refs[i]);
		hist_data->var_refs[i] = NULL;
	}
}

static int init_var_ref(struct hist_field *ref_field,
			struct hist_field *var_field,
			char *system, char *event_name)
{
	int err = 0;

	ref_field->var.idx = var_field->var.idx;
	ref_field->var.hist_data = var_field->hist_data;
	ref_field->size = var_field->size;
	ref_field->is_signed = var_field->is_signed;
	ref_field->flags |= var_field->flags &
		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);

	if (system) {
		ref_field->system = kstrdup(system, GFP_KERNEL);
		if (!ref_field->system)
			return -ENOMEM;
	}

	if (event_name) {
		ref_field->event_name = kstrdup(event_name, GFP_KERNEL);
		if (!ref_field->event_name) {
			err = -ENOMEM;
			goto free;
		}
	}

	if (var_field->var.name) {
		ref_field->name = kstrdup(var_field->var.name, GFP_KERNEL);
		if (!ref_field->name) {
			err = -ENOMEM;
			goto free;
		}
	} else if (var_field->name) {
		ref_field->name = kstrdup(var_field->name, GFP_KERNEL);
		if (!ref_field->name) {
			err = -ENOMEM;
			goto free;
		}
	}

	ref_field->type = kstrdup(var_field->type, GFP_KERNEL);
	if (!ref_field->type) {
		err = -ENOMEM;
		goto free;
	}
 out:
	return err;
 free:
	kfree(ref_field->system);
	kfree(ref_field->event_name);
	kfree(ref_field->name);

	goto out;
}

static int find_var_ref_idx(struct hist_trigger_data *hist_data,
			    struct hist_field *var_field)
{
	struct hist_field *ref_field;
	int i;

	for (i = 0; i < hist_data->n_var_refs; i++) {
		ref_field = hist_data->var_refs[i];
		if (ref_field->var.idx == var_field->var.idx &&
		    ref_field->var.hist_data == var_field->hist_data)
			return i;
	}

	return -ENOENT;
}

/**
 * create_var_ref - Create a variable reference and attach it to trigger
 * @hist_data: The trigger that will be referencing the variable
 * @var_field: The VAR field to create a reference to
 * @system: The optional system string
 * @event_name: The optional event_name string
 *
 * Given a variable hist_field, create a VAR_REF hist_field that
 * represents a reference to it.
 *
 * This function also adds the reference to the trigger that
 * now references the variable.
 *
 * Return: The VAR_REF field if successful, NULL if not
 */
static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
					 struct hist_field *var_field,
					 char *system, char *event_name)
{
	unsigned long flags = HIST_FIELD_FL_VAR_REF;
	struct hist_field *ref_field;
	int i;

	/* Check if the variable already exists */
	for (i = 0; i < hist_data->n_var_refs; i++) {
		ref_field = hist_data->var_refs[i];
		if (ref_field->var.idx == var_field->var.idx &&
		    ref_field->var.hist_data == var_field->hist_data) {
			get_hist_field(ref_field);
			return ref_field;
		}
	}

	ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
	if (ref_field) {
		if (init_var_ref(ref_field, var_field, system, event_name)) {
			destroy_hist_field(ref_field, 0);
			return NULL;
		}

		hist_data->var_refs[hist_data->n_var_refs] = ref_field;
		ref_field->var_ref_idx = hist_data->n_var_refs++;
	}

	return ref_field;
}

static bool is_var_ref(char *var_name)
{
	if (!var_name || strlen(var_name) < 2 || var_name[0] != '$')
		return false;

	return true;
}

static char *field_name_from_var(struct hist_trigger_data *hist_data,
				 char *var_name)
{
	char *name, *field;
	unsigned int i;

	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
		name = hist_data->attrs->var_defs.name[i];

		if (strcmp(var_name, name) == 0) {
			field = hist_data->attrs->var_defs.expr[i];
			if (contains_operator(field) || is_var_ref(field))
				continue;
			return field;
		}
	}

	return NULL;
}

static char *local_field_var_ref(struct hist_trigger_data *hist_data,
				 char *system, char *event_name,
				 char *var_name)
{
	struct trace_event_call *call;

	if (system && event_name) {
		call = hist_data->event_file->event_call;

		if (strcmp(system, call->class->system) != 0)
			return NULL;

		if (strcmp(event_name, trace_event_name(call)) != 0)
			return NULL;
	}

	if (!!system != !!event_name)
		return NULL;

	if (!is_var_ref(var_name))
		return NULL;

	var_name++;

	return field_name_from_var(hist_data, var_name);
}

static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
					char *system, char *event_name,
					char *var_name)
{
	struct hist_field *var_field = NULL, *ref_field = NULL;
	struct trace_array *tr = hist_data->event_file->tr;

	if (!is_var_ref(var_name))
		return NULL;

	var_name++;

	var_field = find_event_var(hist_data, system, event_name, var_name);
	if (var_field)
		ref_field = create_var_ref(hist_data, var_field,
					   system, event_name);

	if (!ref_field)
		hist_err(tr, HIST_ERR_VAR_NOT_FOUND, errpos(var_name));

	return ref_field;
}

static struct ftrace_event_field *
parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
	    char *field_str, unsigned long *flags)
{
	struct ftrace_event_field *field = NULL;
	char *field_name, *modifier, *str;
	struct trace_array *tr = file->tr;

	modifier = str = kstrdup(field_str, GFP_KERNEL);
	if (!modifier)
		return ERR_PTR(-ENOMEM);

	field_name = strsep(&modifier, ".");
	if (modifier) {
		if (strcmp(modifier, "hex") == 0)
			*flags |= HIST_FIELD_FL_HEX;
		else if (strcmp(modifier, "sym") == 0)
			*flags |= HIST_FIELD_FL_SYM;
		else if (strcmp(modifier, "sym-offset") == 0)
			*flags |= HIST_FIELD_FL_SYM_OFFSET;
		else if ((strcmp(modifier, "execname") == 0) &&
			 (strcmp(field_name, "common_pid") == 0))
			*flags |= HIST_FIELD_FL_EXECNAME;
		else if (strcmp(modifier, "syscall") == 0)
			*flags |= HIST_FIELD_FL_SYSCALL;
		else if (strcmp(modifier, "log2") == 0)
			*flags |= HIST_FIELD_FL_LOG2;
		else if (strcmp(modifier, "usecs") == 0)
			*flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
		else {
			hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier));
			field = ERR_PTR(-EINVAL);
			goto out;
		}
	}

	if (strcmp(field_name, "common_timestamp") == 0) {
		*flags |= HIST_FIELD_FL_TIMESTAMP;
		hist_data->enable_timestamps = true;
		if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
			hist_data->attrs->ts_in_usecs = true;
	} else if (strcmp(field_name, "cpu") == 0)
		*flags |= HIST_FIELD_FL_CPU;
	else {
		field = trace_find_event_field(file->event_call, field_name);
		if (!field || !field->size) {
			hist_err(tr, HIST_ERR_FIELD_NOT_FOUND, errpos(field_name));
			field = ERR_PTR(-EINVAL);
			goto out;
		}
	}
 out:
	kfree(str);

	return field;
}

static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
				       struct hist_field *var_ref,
				       char *var_name)
{
	struct hist_field *alias = NULL;
	unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR;

	alias = create_hist_field(hist_data, NULL, flags, var_name);
	if (!alias)
		return NULL;

	alias->fn = var_ref->fn;
	alias->operands[0] = var_ref;

	if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) {
		destroy_hist_field(alias, 0);
		return NULL;
	}

	alias->var_ref_idx = var_ref->var_ref_idx;

	return alias;
}

static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
				     struct trace_event_file *file, char *str,
				     unsigned long *flags, char *var_name)
{
	char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str;
	struct ftrace_event_field *field = NULL;
	struct hist_field *hist_field = NULL;
	int ret = 0;

	s = strchr(str, '.');
	if (s) {
		s = strchr(++s, '.');
		if (s) {
			ref_system = strsep(&str, ".");
			if (!str) {
				ret = -EINVAL;
				goto out;
			}
			ref_event = strsep(&str, ".");
			if (!str) {
				ret = -EINVAL;
				goto out;
			}
			ref_var = str;
		}
	}

	s = local_field_var_ref(hist_data, ref_system, ref_event, ref_var);
	if (!s) {
		hist_field = parse_var_ref(hist_data, ref_system,
					   ref_event, ref_var);
		if (hist_field) {
			if (var_name) {
				hist_field = create_alias(hist_data, hist_field, var_name);
				if (!hist_field) {
					ret = -ENOMEM;
					goto out;
				}
			}
			return hist_field;
		}
	} else
		str = s;

	field = parse_field(hist_data, file, str, flags);
	if (IS_ERR(field)) {
		ret = PTR_ERR(field);
		goto out;
	}

	hist_field = create_hist_field(hist_data, field, *flags, var_name);
	if (!hist_field) {
		ret = -ENOMEM;
		goto out;
	}

	return hist_field;
 out:
	return ERR_PTR(ret);
}

static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
				     struct trace_event_file *file,
				     char *str, unsigned long flags,
				     char *var_name, unsigned int level);

static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
				      struct trace_event_file *file,
				      char *str, unsigned long flags,
				      char *var_name, unsigned int level)
{
	struct hist_field *operand1, *expr = NULL;
	unsigned long operand_flags;
	int ret = 0;
	char *s;

	/* we support only -(xxx) i.e. explicit parens required */

	if (level > 3) {
		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
		ret = -EINVAL;
		goto free;
	}

	str++; /* skip leading '-' */

	s = strchr(str, '(');
	if (s)
		str++;
	else {
		ret = -EINVAL;
		goto free;
	}

	s = strrchr(str, ')');
	if (s)
		*s = '\0';
	else {
		ret = -EINVAL; /* no closing ')' */
		goto free;
	}

	flags |= HIST_FIELD_FL_EXPR;
	expr = create_hist_field(hist_data, NULL, flags, var_name);
	if (!expr) {
		ret = -ENOMEM;
		goto free;
	}

	operand_flags = 0;
	operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
	if (IS_ERR(operand1)) {
		ret = PTR_ERR(operand1);
		goto free;
	}

	expr->flags |= operand1->flags &
		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
	expr->fn = hist_field_unary_minus;
	expr->operands[0] = operand1;
	expr->operator = FIELD_OP_UNARY_MINUS;
	expr->name = expr_str(expr, 0);
	expr->type = kstrdup(operand1->type, GFP_KERNEL);
	if (!expr->type) {
		ret = -ENOMEM;
		goto free;
	}

	return expr;
 free:
	destroy_hist_field(expr, 0);
	return ERR_PTR(ret);
}

static int check_expr_operands(struct trace_array *tr,
			       struct hist_field *operand1,
			       struct hist_field *operand2)
{
	unsigned long operand1_flags = operand1->flags;
	unsigned long operand2_flags = operand2->flags;

	if ((operand1_flags & HIST_FIELD_FL_VAR_REF) ||
	    (operand1_flags & HIST_FIELD_FL_ALIAS)) {
		struct hist_field *var;

		var = find_var_field(operand1->var.hist_data, operand1->name);
		if (!var)
			return -EINVAL;
		operand1_flags = var->flags;
	}

	if ((operand2_flags & HIST_FIELD_FL_VAR_REF) ||
	    (operand2_flags & HIST_FIELD_FL_ALIAS)) {
		struct hist_field *var;

		var = find_var_field(operand2->var.hist_data, operand2->name);
		if (!var)
			return -EINVAL;
		operand2_flags = var->flags;
	}

	if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
	    (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
		hist_err(tr, HIST_ERR_TIMESTAMP_MISMATCH, 0);
		return -EINVAL;
	}

	return 0;
}

static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
				     struct trace_event_file *file,
				     char *str, unsigned long flags,
				     char *var_name, unsigned int level)
{
	struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
	unsigned long operand_flags;
	int field_op, ret = -EINVAL;
	char *sep, *operand1_str;

	if (level > 3) {
		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
		return ERR_PTR(-EINVAL);
	}

	field_op = contains_operator(str);

	if (field_op == FIELD_OP_NONE)
		return parse_atom(hist_data, file, str, &flags, var_name);

	if (field_op == FIELD_OP_UNARY_MINUS)
		return parse_unary(hist_data, file, str, flags, var_name, ++level);

	switch (field_op) {
	case FIELD_OP_MINUS:
		sep = "-";
		break;
	case FIELD_OP_PLUS:
		sep = "+";
		break;
	default:
		goto free;
	}

	operand1_str = strsep(&str, sep);
	if (!operand1_str || !str)
		goto free;

	operand_flags = 0;
	operand1 = parse_atom(hist_data, file, operand1_str,
			      &operand_flags, NULL);
	if (IS_ERR(operand1)) {
		ret = PTR_ERR(operand1);
		operand1 = NULL;
		goto free;
	}

	/* rest of string could be another expression e.g. b+c in a+b+c */
	operand_flags = 0;
	operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
	if (IS_ERR(operand2)) {
		ret = PTR_ERR(operand2);
		operand2 = NULL;
		goto free;
	}

	ret = check_expr_operands(file->tr, operand1, operand2);
	if (ret)
		goto free;

	flags |= HIST_FIELD_FL_EXPR;

	flags |= operand1->flags &
		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);

	expr = create_hist_field(hist_data, NULL, flags, var_name);
	if (!expr) {
		ret = -ENOMEM;
		goto free;
	}

	operand1->read_once = true;
	operand2->read_once = true;

	expr->operands[0] = operand1;
	expr->operands[1] = operand2;
	expr->operator = field_op;
	expr->name = expr_str(expr, 0);
	expr->type = kstrdup(operand1->type, GFP_KERNEL);
	if (!expr->type) {
		ret = -ENOMEM;
		goto free;
	}

	switch (field_op) {
	case FIELD_OP_MINUS:
		expr->fn = hist_field_minus;
		break;
	case FIELD_OP_PLUS:
		expr->fn = hist_field_plus;
		break;
	default:
		ret = -EINVAL;
		goto free;
	}

	return expr;
 free:
	destroy_hist_field(operand1, 0);
	destroy_hist_field(operand2, 0);
	destroy_hist_field(expr, 0);

	return ERR_PTR(ret);
}

static char *find_trigger_filter(struct hist_trigger_data *hist_data,
				 struct trace_event_file *file)
{
	struct event_trigger_data *test;

	lockdep_assert_held(&event_mutex);

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			if (test->private_data == hist_data)
				return test->filter_str;
		}
	}

	return NULL;
}

static struct event_command trigger_hist_cmd;
static int event_hist_trigger_func(struct event_command *cmd_ops,
				   struct trace_event_file *file,
				   char *glob, char *cmd, char *param);

static bool compatible_keys(struct hist_trigger_data *target_hist_data,
			    struct hist_trigger_data *hist_data,
			    unsigned int n_keys)
{
	struct hist_field *target_hist_field, *hist_field;
	unsigned int n, i, j;

	if (hist_data->n_fields - hist_data->n_vals != n_keys)
		return false;

	i = hist_data->n_vals;
	j = target_hist_data->n_vals;

	for (n = 0; n < n_keys; n++) {
		hist_field = hist_data->fields[i + n];
		target_hist_field = target_hist_data->fields[j + n];

		if (strcmp(hist_field->type, target_hist_field->type) != 0)
			return false;
		if (hist_field->size != target_hist_field->size)
			return false;
		if (hist_field->is_signed != target_hist_field->is_signed)
			return false;
	}

	return true;
}

static struct hist_trigger_data *
find_compatible_hist(struct hist_trigger_data *target_hist_data,
		     struct trace_event_file *file)
{
	struct hist_trigger_data *hist_data;
	struct event_trigger_data *test;
	unsigned int n_keys;

	lockdep_assert_held(&event_mutex);

	n_keys = target_hist_data->n_fields - target_hist_data->n_vals;

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			hist_data = test->private_data;

			if (compatible_keys(target_hist_data, hist_data, n_keys))
				return hist_data;
		}
	}

	return NULL;
}

static struct trace_event_file *event_file(struct trace_array *tr,
					   char *system, char *event_name)
{
	struct trace_event_file *file;

	file = __find_event_file(tr, system, event_name);
	if (!file)
		return ERR_PTR(-EINVAL);

	return file;
}

static struct hist_field *
find_synthetic_field_var(struct hist_trigger_data *target_hist_data,
			 char *system, char *event_name, char *field_name)
{
	struct hist_field *event_var;
	char *synthetic_name;

	synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
	if (!synthetic_name)
		return ERR_PTR(-ENOMEM);

	strcpy(synthetic_name, "synthetic_");
	strcat(synthetic_name, field_name);

	event_var = find_event_var(target_hist_data, system, event_name, synthetic_name);

	kfree(synthetic_name);

	return event_var;
}

/**
 * create_field_var_hist - Automatically create a histogram and var for a field
 * @target_hist_data: The target hist trigger
 * @subsys_name: Optional subsystem name
 * @event_name: Optional event name
 * @field_name: The name of the field (and the resulting variable)
 *
 * Hist trigger actions fetch data from variables, not directly from
 * events.  However, for convenience, users are allowed to directly
 * specify an event field in an action, which will be automatically
 * converted into a variable on their behalf.

 * If a user specifies a field on an event that isn't the event the
 * histogram currently being defined (the target event histogram), the
 * only way that can be accomplished is if a new hist trigger is
 * created and the field variable defined on that.
 *
 * This function creates a new histogram compatible with the target
 * event (meaning a histogram with the same key as the target
 * histogram), and creates a variable for the specified field, but
 * with 'synthetic_' prepended to the variable name in order to avoid
 * collision with normal field variables.
 *
 * Return: The variable created for the field.
 */
static struct hist_field *
create_field_var_hist(struct hist_trigger_data *target_hist_data,
		      char *subsys_name, char *event_name, char *field_name)
{
	struct trace_array *tr = target_hist_data->event_file->tr;
	struct hist_field *event_var = ERR_PTR(-EINVAL);
	struct hist_trigger_data *hist_data;
	unsigned int i, n, first = true;
	struct field_var_hist *var_hist;
	struct trace_event_file *file;
	struct hist_field *key_field;
	char *saved_filter;
	char *cmd;
	int ret;

	if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
		return ERR_PTR(-EINVAL);
	}

	file = event_file(tr, subsys_name, event_name);

	if (IS_ERR(file)) {
		hist_err(tr, HIST_ERR_EVENT_FILE_NOT_FOUND, errpos(field_name));
		ret = PTR_ERR(file);
		return ERR_PTR(ret);
	}

	/*
	 * Look for a histogram compatible with target.  We'll use the
	 * found histogram specification to create a new matching
	 * histogram with our variable on it.  target_hist_data is not
	 * yet a registered histogram so we can't use that.
	 */
	hist_data = find_compatible_hist(target_hist_data, file);
	if (!hist_data) {
		hist_err(tr, HIST_ERR_HIST_NOT_FOUND, errpos(field_name));
		return ERR_PTR(-EINVAL);
	}

	/* See if a synthetic field variable has already been created */
	event_var = find_synthetic_field_var(target_hist_data, subsys_name,
					     event_name, field_name);
	if (!IS_ERR_OR_NULL(event_var))
		return event_var;

	var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL);
	if (!var_hist)
		return ERR_PTR(-ENOMEM);

	cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
	if (!cmd) {
		kfree(var_hist);
		return ERR_PTR(-ENOMEM);
	}

	/* Use the same keys as the compatible histogram */
	strcat(cmd, "keys=");

	for_each_hist_key_field(i, hist_data) {
		key_field = hist_data->fields[i];
		if (!first)
			strcat(cmd, ",");
		strcat(cmd, key_field->field->name);
		first = false;
	}

	/* Create the synthetic field variable specification */
	strcat(cmd, ":synthetic_");
	strcat(cmd, field_name);
	strcat(cmd, "=");
	strcat(cmd, field_name);

	/* Use the same filter as the compatible histogram */
	saved_filter = find_trigger_filter(hist_data, file);
	if (saved_filter) {
		strcat(cmd, " if ");
		strcat(cmd, saved_filter);
	}

	var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
	if (!var_hist->cmd) {
		kfree(cmd);
		kfree(var_hist);
		return ERR_PTR(-ENOMEM);
	}

	/* Save the compatible histogram information */
	var_hist->hist_data = hist_data;

	/* Create the new histogram with our variable */
	ret = event_hist_trigger_func(&trigger_hist_cmd, file,
				      "", "hist", cmd);
	if (ret) {
		kfree(cmd);
		kfree(var_hist->cmd);
		kfree(var_hist);
		hist_err(tr, HIST_ERR_HIST_CREATE_FAIL, errpos(field_name));
		return ERR_PTR(ret);
	}

	kfree(cmd);

	/* If we can't find the variable, something went wrong */
	event_var = find_synthetic_field_var(target_hist_data, subsys_name,
					     event_name, field_name);
	if (IS_ERR_OR_NULL(event_var)) {
		kfree(var_hist->cmd);
		kfree(var_hist);
		hist_err(tr, HIST_ERR_SYNTH_VAR_NOT_FOUND, errpos(field_name));
		return ERR_PTR(-EINVAL);
	}

	n = target_hist_data->n_field_var_hists;
	target_hist_data->field_var_hists[n] = var_hist;
	target_hist_data->n_field_var_hists++;

	return event_var;
}

static struct hist_field *
find_target_event_var(struct hist_trigger_data *hist_data,
		      char *subsys_name, char *event_name, char *var_name)
{
	struct trace_event_file *file = hist_data->event_file;
	struct hist_field *hist_field = NULL;

	if (subsys_name) {
		struct trace_event_call *call;

		if (!event_name)
			return NULL;

		call = file->event_call;

		if (strcmp(subsys_name, call->class->system) != 0)
			return NULL;

		if (strcmp(event_name, trace_event_name(call)) != 0)
			return NULL;
	}

	hist_field = find_var_field(hist_data, var_name);

	return hist_field;
}

static inline void __update_field_vars(struct tracing_map_elt *elt,
				       struct ring_buffer_event *rbe,
				       void *rec,
				       struct field_var **field_vars,
				       unsigned int n_field_vars,
				       unsigned int field_var_str_start)
{
	struct hist_elt_data *elt_data = elt->private_data;
	unsigned int i, j, var_idx;
	u64 var_val;

	for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
		struct field_var *field_var = field_vars[i];
		struct hist_field *var = field_var->var;
		struct hist_field *val = field_var->val;

		var_val = val->fn(val, elt, rbe, rec);
		var_idx = var->var.idx;

		if (val->flags & HIST_FIELD_FL_STRING) {
			char *str = elt_data->field_var_str[j++];
			char *val_str = (char *)(uintptr_t)var_val;

			strscpy(str, val_str, STR_VAR_LEN_MAX);
			var_val = (u64)(uintptr_t)str;
		}
		tracing_map_set_var(elt, var_idx, var_val);
	}
}

static void update_field_vars(struct hist_trigger_data *hist_data,
			      struct tracing_map_elt *elt,
			      struct ring_buffer_event *rbe,
			      void *rec)
{
	__update_field_vars(elt, rbe, rec, hist_data->field_vars,
			    hist_data->n_field_vars, 0);
}

static void save_track_data_vars(struct hist_trigger_data *hist_data,
				 struct tracing_map_elt *elt, void *rec,
				 struct ring_buffer_event *rbe, void *key,
				 struct action_data *data, u64 *var_ref_vals)
{
	__update_field_vars(elt, rbe, rec, hist_data->save_vars,
			    hist_data->n_save_vars, hist_data->n_field_var_str);
}

static struct hist_field *create_var(struct hist_trigger_data *hist_data,
				     struct trace_event_file *file,
				     char *name, int size, const char *type)
{
	struct hist_field *var;
	int idx;

	if (find_var(hist_data, file, name) && !hist_data->remove) {
		var = ERR_PTR(-EINVAL);
		goto out;
	}

	var = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
	if (!var) {
		var = ERR_PTR(-ENOMEM);
		goto out;
	}

	idx = tracing_map_add_var(hist_data->map);
	if (idx < 0) {
		kfree(var);
		var = ERR_PTR(-EINVAL);
		goto out;
	}

	var->ref = 1;
	var->flags = HIST_FIELD_FL_VAR;
	var->var.idx = idx;
	var->var.hist_data = var->hist_data = hist_data;
	var->size = size;
	var->var.name = kstrdup(name, GFP_KERNEL);
	var->type = kstrdup(type, GFP_KERNEL);
	if (!var->var.name || !var->type) {
		kfree(var->var.name);
		kfree(var->type);
		kfree(var);
		var = ERR_PTR(-ENOMEM);
	}
 out:
	return var;
}

static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
					  struct trace_event_file *file,
					  char *field_name)
{
	struct hist_field *val = NULL, *var = NULL;
	unsigned long flags = HIST_FIELD_FL_VAR;
	struct trace_array *tr = file->tr;
	struct field_var *field_var;
	int ret = 0;

	if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
		ret = -EINVAL;
		goto err;
	}

	val = parse_atom(hist_data, file, field_name, &flags, NULL);
	if (IS_ERR(val)) {
		hist_err(tr, HIST_ERR_FIELD_VAR_PARSE_FAIL, errpos(field_name));
		ret = PTR_ERR(val);
		goto err;
	}

	var = create_var(hist_data, file, field_name, val->size, val->type);
	if (IS_ERR(var)) {
		hist_err(tr, HIST_ERR_VAR_CREATE_FIND_FAIL, errpos(field_name));
		kfree(val);
		ret = PTR_ERR(var);
		goto err;
	}

	field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
	if (!field_var) {
		kfree(val);
		kfree(var);
		ret =  -ENOMEM;
		goto err;
	}

	field_var->var = var;
	field_var->val = val;
 out:
	return field_var;
 err:
	field_var = ERR_PTR(ret);
	goto out;
}

/**
 * create_target_field_var - Automatically create a variable for a field
 * @target_hist_data: The target hist trigger
 * @subsys_name: Optional subsystem name
 * @event_name: Optional event name
 * @var_name: The name of the field (and the resulting variable)
 *
 * Hist trigger actions fetch data from variables, not directly from
 * events.  However, for convenience, users are allowed to directly
 * specify an event field in an action, which will be automatically
 * converted into a variable on their behalf.

 * This function creates a field variable with the name var_name on
 * the hist trigger currently being defined on the target event.  If
 * subsys_name and event_name are specified, this function simply
 * verifies that they do in fact match the target event subsystem and
 * event name.
 *
 * Return: The variable created for the field.
 */
static struct field_var *
create_target_field_var(struct hist_trigger_data *target_hist_data,
			char *subsys_name, char *event_name, char *var_name)
{
	struct trace_event_file *file = target_hist_data->event_file;

	if (subsys_name) {
		struct trace_event_call *call;

		if (!event_name)
			return NULL;

		call = file->event_call;

		if (strcmp(subsys_name, call->class->system) != 0)
			return NULL;

		if (strcmp(event_name, trace_event_name(call)) != 0)
			return NULL;
	}

	return create_field_var(target_hist_data, file, var_name);
}

static bool check_track_val_max(u64 track_val, u64 var_val)
{
	if (var_val <= track_val)
		return false;

	return true;
}

static bool check_track_val_changed(u64 track_val, u64 var_val)
{
	if (var_val == track_val)
		return false;

	return true;
}

static u64 get_track_val(struct hist_trigger_data *hist_data,
			 struct tracing_map_elt *elt,
			 struct action_data *data)
{
	unsigned int track_var_idx = data->track_data.track_var->var.idx;
	u64 track_val;

	track_val = tracing_map_read_var(elt, track_var_idx);

	return track_val;
}

static void save_track_val(struct hist_trigger_data *hist_data,
			   struct tracing_map_elt *elt,
			   struct action_data *data, u64 var_val)
{
	unsigned int track_var_idx = data->track_data.track_var->var.idx;

	tracing_map_set_var(elt, track_var_idx, var_val);
}

static void save_track_data(struct hist_trigger_data *hist_data,
			    struct tracing_map_elt *elt, void *rec,
			    struct ring_buffer_event *rbe, void *key,
			    struct action_data *data, u64 *var_ref_vals)
{
	if (data->track_data.save_data)
		data->track_data.save_data(hist_data, elt, rec, rbe, key, data, var_ref_vals);
}

static bool check_track_val(struct tracing_map_elt *elt,
			    struct action_data *data,
			    u64 var_val)
{
	struct hist_trigger_data *hist_data;
	u64 track_val;

	hist_data = data->track_data.track_var->hist_data;
	track_val = get_track_val(hist_data, elt, data);

	return data->track_data.check_val(track_val, var_val);
}

#ifdef CONFIG_TRACER_SNAPSHOT
static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
{
	/* called with tr->max_lock held */
	struct track_data *track_data = tr->cond_snapshot->cond_data;
	struct hist_elt_data *elt_data, *track_elt_data;
	struct snapshot_context *context = cond_data;
	struct action_data *action;
	u64 track_val;

	if (!track_data)
		return false;

	action = track_data->action_data;

	track_val = get_track_val(track_data->hist_data, context->elt,
				  track_data->action_data);

	if (!action->track_data.check_val(track_data->track_val, track_val))
		return false;

	track_data->track_val = track_val;
	memcpy(track_data->key, context->key, track_data->key_len);

	elt_data = context->elt->private_data;
	track_elt_data = track_data->elt.private_data;
	if (elt_data->comm)
		strncpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);

	track_data->updated = true;

	return true;
}

static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
				     struct tracing_map_elt *elt, void *rec,
				     struct ring_buffer_event *rbe, void *key,
				     struct action_data *data,
				     u64 *var_ref_vals)
{
	struct trace_event_file *file = hist_data->event_file;
	struct snapshot_context context;

	context.elt = elt;
	context.key = key;

	tracing_snapshot_cond(file->tr, &context);
}

static void hist_trigger_print_key(struct seq_file *m,
				   struct hist_trigger_data *hist_data,
				   void *key,
				   struct tracing_map_elt *elt);

static struct action_data *snapshot_action(struct hist_trigger_data *hist_data)
{
	unsigned int i;

	if (!hist_data->n_actions)
		return NULL;

	for (i = 0; i < hist_data->n_actions; i++) {
		struct action_data *data = hist_data->actions[i];

		if (data->action == ACTION_SNAPSHOT)
			return data;
	}

	return NULL;
}

static void track_data_snapshot_print(struct seq_file *m,
				      struct hist_trigger_data *hist_data)
{
	struct trace_event_file *file = hist_data->event_file;
	struct track_data *track_data;
	struct action_data *action;

	track_data = tracing_cond_snapshot_data(file->tr);
	if (!track_data)
		return;

	if (!track_data->updated)
		return;

	action = snapshot_action(hist_data);
	if (!action)
		return;

	seq_puts(m, "\nSnapshot taken (see tracing/snapshot).  Details:\n");
	seq_printf(m, "\ttriggering value { %s(%s) }: %10llu",
		   action->handler == HANDLER_ONMAX ? "onmax" : "onchange",
		   action->track_data.var_str, track_data->track_val);

	seq_puts(m, "\ttriggered by event with key: ");
	hist_trigger_print_key(m, hist_data, track_data->key, &track_data->elt);
	seq_putc(m, '\n');
}
#else
static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
{
	return false;
}
static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
				     struct tracing_map_elt *elt, void *rec,
				     struct ring_buffer_event *rbe, void *key,
				     struct action_data *data,
				     u64 *var_ref_vals) {}
static void track_data_snapshot_print(struct seq_file *m,
				      struct hist_trigger_data *hist_data) {}
#endif /* CONFIG_TRACER_SNAPSHOT */

static void track_data_print(struct seq_file *m,
			     struct hist_trigger_data *hist_data,
			     struct tracing_map_elt *elt,
			     struct action_data *data)
{
	u64 track_val = get_track_val(hist_data, elt, data);
	unsigned int i, save_var_idx;

	if (data->handler == HANDLER_ONMAX)
		seq_printf(m, "\n\tmax: %10llu", track_val);
	else if (data->handler == HANDLER_ONCHANGE)
		seq_printf(m, "\n\tchanged: %10llu", track_val);

	if (data->action == ACTION_SNAPSHOT)
		return;

	for (i = 0; i < hist_data->n_save_vars; i++) {
		struct hist_field *save_val = hist_data->save_vars[i]->val;
		struct hist_field *save_var = hist_data->save_vars[i]->var;
		u64 val;

		save_var_idx = save_var->var.idx;

		val = tracing_map_read_var(elt, save_var_idx);

		if (save_val->flags & HIST_FIELD_FL_STRING) {
			seq_printf(m, "  %s: %-32s", save_var->var.name,
				   (char *)(uintptr_t)(val));
		} else
			seq_printf(m, "  %s: %10llu", save_var->var.name, val);
	}
}

static void ontrack_action(struct hist_trigger_data *hist_data,
			   struct tracing_map_elt *elt, void *rec,
			   struct ring_buffer_event *rbe, void *key,
			   struct action_data *data, u64 *var_ref_vals)
{
	u64 var_val = var_ref_vals[data->track_data.var_ref->var_ref_idx];

	if (check_track_val(elt, data, var_val)) {
		save_track_val(hist_data, elt, data, var_val);
		save_track_data(hist_data, elt, rec, rbe, key, data, var_ref_vals);
	}
}

static void action_data_destroy(struct action_data *data)
{
	unsigned int i;

	lockdep_assert_held(&event_mutex);

	kfree(data->action_name);

	for (i = 0; i < data->n_params; i++)
		kfree(data->params[i]);

	if (data->synth_event)
		data->synth_event->ref--;

	kfree(data->synth_event_name);

	kfree(data);
}

static void track_data_destroy(struct hist_trigger_data *hist_data,
			       struct action_data *data)
{
	struct trace_event_file *file = hist_data->event_file;

	destroy_hist_field(data->track_data.track_var, 0);

	if (data->action == ACTION_SNAPSHOT) {
		struct track_data *track_data;

		track_data = tracing_cond_snapshot_data(file->tr);
		if (track_data && track_data->hist_data == hist_data) {
			tracing_snapshot_cond_disable(file->tr);
			track_data_free(track_data);
		}
	}

	kfree(data->track_data.var_str);

	action_data_destroy(data);
}

static int action_create(struct hist_trigger_data *hist_data,
			 struct action_data *data);

static int track_data_create(struct hist_trigger_data *hist_data,
			     struct action_data *data)
{
	struct hist_field *var_field, *ref_field, *track_var = NULL;
	struct trace_event_file *file = hist_data->event_file;
	struct trace_array *tr = file->tr;
	char *track_data_var_str;
	int ret = 0;

	track_data_var_str = data->track_data.var_str;
	if (track_data_var_str[0] != '$') {
		hist_err(tr, HIST_ERR_ONX_NOT_VAR, errpos(track_data_var_str));
		return -EINVAL;
	}
	track_data_var_str++;

	var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
	if (!var_field) {
		hist_err(tr, HIST_ERR_ONX_VAR_NOT_FOUND, errpos(track_data_var_str));
		return -EINVAL;
	}

	ref_field = create_var_ref(hist_data, var_field, NULL, NULL);
	if (!ref_field)
		return -ENOMEM;

	data->track_data.var_ref = ref_field;

	if (data->handler == HANDLER_ONMAX)
		track_var = create_var(hist_data, file, "__max", sizeof(u64), "u64");
	if (IS_ERR(track_var)) {
		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
		ret = PTR_ERR(track_var);
		goto out;
	}

	if (data->handler == HANDLER_ONCHANGE)
		track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
	if (IS_ERR(track_var)) {
		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
		ret = PTR_ERR(track_var);
		goto out;
	}
	data->track_data.track_var = track_var;

	ret = action_create(hist_data, data);
 out:
	return ret;
}

static int parse_action_params(struct trace_array *tr, char *params,
			       struct action_data *data)
{
	char *param, *saved_param;
	bool first_param = true;
	int ret = 0;

	while (params) {
		if (data->n_params >= SYNTH_FIELDS_MAX) {
			hist_err(tr, HIST_ERR_TOO_MANY_PARAMS, 0);
			goto out;
		}

		param = strsep(&params, ",");
		if (!param) {
			hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, 0);
			ret = -EINVAL;
			goto out;
		}

		param = strstrip(param);
		if (strlen(param) < 2) {
			hist_err(tr, HIST_ERR_INVALID_PARAM, errpos(param));
			ret = -EINVAL;
			goto out;
		}

		saved_param = kstrdup(param, GFP_KERNEL);
		if (!saved_param) {
			ret = -ENOMEM;
			goto out;
		}

		if (first_param && data->use_trace_keyword) {
			data->synth_event_name = saved_param;
			first_param = false;
			continue;
		}
		first_param = false;

		data->params[data->n_params++] = saved_param;
	}
 out:
	return ret;
}

static int action_parse(struct trace_array *tr, char *str, struct action_data *data,
			enum handler_id handler)
{
	char *action_name;
	int ret = 0;

	strsep(&str, ".");
	if (!str) {
		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
		ret = -EINVAL;
		goto out;
	}

	action_name = strsep(&str, "(");
	if (!action_name || !str) {
		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
		ret = -EINVAL;
		goto out;
	}

	if (str_has_prefix(action_name, "save")) {
		char *params = strsep(&str, ")");

		if (!params) {
			hist_err(tr, HIST_ERR_NO_SAVE_PARAMS, 0);
			ret = -EINVAL;
			goto out;
		}

		ret = parse_action_params(tr, params, data);
		if (ret)
			goto out;

		if (handler == HANDLER_ONMAX)
			data->track_data.check_val = check_track_val_max;
		else if (handler == HANDLER_ONCHANGE)
			data->track_data.check_val = check_track_val_changed;
		else {
			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
			ret = -EINVAL;
			goto out;
		}

		data->track_data.save_data = save_track_data_vars;
		data->fn = ontrack_action;
		data->action = ACTION_SAVE;
	} else if (str_has_prefix(action_name, "snapshot")) {
		char *params = strsep(&str, ")");

		if (!str) {
			hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(params));
			ret = -EINVAL;
			goto out;
		}

		if (handler == HANDLER_ONMAX)
			data->track_data.check_val = check_track_val_max;
		else if (handler == HANDLER_ONCHANGE)
			data->track_data.check_val = check_track_val_changed;
		else {
			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
			ret = -EINVAL;
			goto out;
		}

		data->track_data.save_data = save_track_data_snapshot;
		data->fn = ontrack_action;
		data->action = ACTION_SNAPSHOT;
	} else {
		char *params = strsep(&str, ")");

		if (str_has_prefix(action_name, "trace"))
			data->use_trace_keyword = true;

		if (params) {
			ret = parse_action_params(tr, params, data);
			if (ret)
				goto out;
		}

		if (handler == HANDLER_ONMAX)
			data->track_data.check_val = check_track_val_max;
		else if (handler == HANDLER_ONCHANGE)
			data->track_data.check_val = check_track_val_changed;

		if (handler != HANDLER_ONMATCH) {
			data->track_data.save_data = action_trace;
			data->fn = ontrack_action;
		} else
			data->fn = action_trace;

		data->action = ACTION_TRACE;
	}

	data->action_name = kstrdup(action_name, GFP_KERNEL);
	if (!data->action_name) {
		ret = -ENOMEM;
		goto out;
	}

	data->handler = handler;
 out:
	return ret;
}

static struct action_data *track_data_parse(struct hist_trigger_data *hist_data,
					    char *str, enum handler_id handler)
{
	struct action_data *data;
	int ret = -EINVAL;
	char *var_str;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return ERR_PTR(-ENOMEM);

	var_str = strsep(&str, ")");
	if (!var_str || !str) {
		ret = -EINVAL;
		goto free;
	}

	data->track_data.var_str = kstrdup(var_str, GFP_KERNEL);
	if (!data->track_data.var_str) {
		ret = -ENOMEM;
		goto free;
	}

	ret = action_parse(hist_data->event_file->tr, str, data, handler);
	if (ret)
		goto free;
 out:
	return data;
 free:
	track_data_destroy(hist_data, data);
	data = ERR_PTR(ret);
	goto out;
}

static void onmatch_destroy(struct action_data *data)
{
	kfree(data->match_data.event);
	kfree(data->match_data.event_system);

	action_data_destroy(data);
}

static void destroy_field_var(struct field_var *field_var)
{
	if (!field_var)
		return;

	destroy_hist_field(field_var->var, 0);
	destroy_hist_field(field_var->val, 0);

	kfree(field_var);
}

static void destroy_field_vars(struct hist_trigger_data *hist_data)
{
	unsigned int i;

	for (i = 0; i < hist_data->n_field_vars; i++)
		destroy_field_var(hist_data->field_vars[i]);

	for (i = 0; i < hist_data->n_save_vars; i++)
		destroy_field_var(hist_data->save_vars[i]);
}

static void save_field_var(struct hist_trigger_data *hist_data,
			   struct field_var *field_var)
{
	hist_data->field_vars[hist_data->n_field_vars++] = field_var;

	if (field_var->val->flags & HIST_FIELD_FL_STRING)
		hist_data->n_field_var_str++;
}


static int check_synth_field(struct synth_event *event,
			     struct hist_field *hist_field,
			     unsigned int field_pos)
{
	struct synth_field *field;

	if (field_pos >= event->n_fields)
		return -EINVAL;

	field = event->fields[field_pos];

	/*
	 * A dynamic string synth field can accept static or
	 * dynamic. A static string synth field can only accept a
	 * same-sized static string, which is checked for later.
	 */
	if (strstr(hist_field->type, "char[") && field->is_string
	    && field->is_dynamic)
		return 0;

	if (strcmp(field->type, hist_field->type) != 0) {
		if (field->size != hist_field->size ||
		    field->is_signed != hist_field->is_signed)
			return -EINVAL;
	}

	return 0;
}

static struct hist_field *
trace_action_find_var(struct hist_trigger_data *hist_data,
		      struct action_data *data,
		      char *system, char *event, char *var)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_field *hist_field;

	var++; /* skip '$' */

	hist_field = find_target_event_var(hist_data, system, event, var);
	if (!hist_field) {
		if (!system && data->handler == HANDLER_ONMATCH) {
			system = data->match_data.event_system;
			event = data->match_data.event;
		}

		hist_field = find_event_var(hist_data, system, event, var);
	}

	if (!hist_field)
		hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, errpos(var));

	return hist_field;
}

static struct hist_field *
trace_action_create_field_var(struct hist_trigger_data *hist_data,
			      struct action_data *data, char *system,
			      char *event, char *var)
{
	struct hist_field *hist_field = NULL;
	struct field_var *field_var;

	/*
	 * First try to create a field var on the target event (the
	 * currently being defined).  This will create a variable for
	 * unqualified fields on the target event, or if qualified,
	 * target fields that have qualified names matching the target.
	 */
	field_var = create_target_field_var(hist_data, system, event, var);

	if (field_var && !IS_ERR(field_var)) {
		save_field_var(hist_data, field_var);
		hist_field = field_var->var;
	} else {
		field_var = NULL;
		/*
		 * If no explicit system.event is specfied, default to
		 * looking for fields on the onmatch(system.event.xxx)
		 * event.
		 */
		if (!system && data->handler == HANDLER_ONMATCH) {
			system = data->match_data.event_system;
			event = data->match_data.event;
		}

		/*
		 * At this point, we're looking at a field on another
		 * event.  Because we can't modify a hist trigger on
		 * another event to add a variable for a field, we need
		 * to create a new trigger on that event and create the
		 * variable at the same time.
		 */
		hist_field = create_field_var_hist(hist_data, system, event, var);
		if (IS_ERR(hist_field))
			goto free;
	}
 out:
	return hist_field;
 free:
	destroy_field_var(field_var);
	hist_field = NULL;
	goto out;
}

static int trace_action_create(struct hist_trigger_data *hist_data,
			       struct action_data *data)
{
	struct trace_array *tr = hist_data->event_file->tr;
	char *event_name, *param, *system = NULL;
	struct hist_field *hist_field, *var_ref;
	unsigned int i;
	unsigned int field_pos = 0;
	struct synth_event *event;
	char *synth_event_name;
	int var_ref_idx, ret = 0;

	lockdep_assert_held(&event_mutex);

	if (data->use_trace_keyword)
		synth_event_name = data->synth_event_name;
	else
		synth_event_name = data->action_name;

	event = find_synth_event(synth_event_name);
	if (!event) {
		hist_err(tr, HIST_ERR_SYNTH_EVENT_NOT_FOUND, errpos(synth_event_name));
		return -EINVAL;
	}

	event->ref++;

	for (i = 0; i < data->n_params; i++) {
		char *p;

		p = param = kstrdup(data->params[i], GFP_KERNEL);
		if (!param) {
			ret = -ENOMEM;
			goto err;
		}

		system = strsep(&param, ".");
		if (!param) {
			param = (char *)system;
			system = event_name = NULL;
		} else {
			event_name = strsep(&param, ".");
			if (!param) {
				kfree(p);
				ret = -EINVAL;
				goto err;
			}
		}

		if (param[0] == '$')
			hist_field = trace_action_find_var(hist_data, data,
							   system, event_name,
							   param);
		else
			hist_field = trace_action_create_field_var(hist_data,
								   data,
								   system,
								   event_name,
								   param);

		if (!hist_field) {
			kfree(p);
			ret = -EINVAL;
			goto err;
		}

		if (check_synth_field(event, hist_field, field_pos) == 0) {
			var_ref = create_var_ref(hist_data, hist_field,
						 system, event_name);
			if (!var_ref) {
				kfree(p);
				ret = -ENOMEM;
				goto err;
			}

			var_ref_idx = find_var_ref_idx(hist_data, var_ref);
			if (WARN_ON(var_ref_idx < 0)) {
				ret = var_ref_idx;
				goto err;
			}

			data->var_ref_idx[i] = var_ref_idx;

			field_pos++;
			kfree(p);
			continue;
		}

		hist_err(tr, HIST_ERR_SYNTH_TYPE_MISMATCH, errpos(param));
		kfree(p);
		ret = -EINVAL;
		goto err;
	}

	if (field_pos != event->n_fields) {
		hist_err(tr, HIST_ERR_SYNTH_COUNT_MISMATCH, errpos(event->name));
		ret = -EINVAL;
		goto err;
	}

	data->synth_event = event;
 out:
	return ret;
 err:
	event->ref--;

	goto out;
}

static int action_create(struct hist_trigger_data *hist_data,
			 struct action_data *data)
{
	struct trace_event_file *file = hist_data->event_file;
	struct trace_array *tr = file->tr;
	struct track_data *track_data;
	struct field_var *field_var;
	unsigned int i;
	char *param;
	int ret = 0;

	if (data->action == ACTION_TRACE)
		return trace_action_create(hist_data, data);

	if (data->action == ACTION_SNAPSHOT) {
		track_data = track_data_alloc(hist_data->key_size, data, hist_data);
		if (IS_ERR(track_data)) {
			ret = PTR_ERR(track_data);
			goto out;
		}

		ret = tracing_snapshot_cond_enable(file->tr, track_data,
						   cond_snapshot_update);
		if (ret)
			track_data_free(track_data);

		goto out;
	}

	if (data->action == ACTION_SAVE) {
		if (hist_data->n_save_vars) {
			ret = -EEXIST;
			hist_err(tr, HIST_ERR_TOO_MANY_SAVE_ACTIONS, 0);
			goto out;
		}

		for (i = 0; i < data->n_params; i++) {
			param = kstrdup(data->params[i], GFP_KERNEL);
			if (!param) {
				ret = -ENOMEM;
				goto out;
			}

			field_var = create_target_field_var(hist_data, NULL, NULL, param);
			if (IS_ERR(field_var)) {
				hist_err(tr, HIST_ERR_FIELD_VAR_CREATE_FAIL,
					 errpos(param));
				ret = PTR_ERR(field_var);
				kfree(param);
				goto out;
			}

			hist_data->save_vars[hist_data->n_save_vars++] = field_var;
			if (field_var->val->flags & HIST_FIELD_FL_STRING)
				hist_data->n_save_var_str++;
			kfree(param);
		}
	}
 out:
	return ret;
}

static int onmatch_create(struct hist_trigger_data *hist_data,
			  struct action_data *data)
{
	return action_create(hist_data, data);
}

static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
{
	char *match_event, *match_event_system;
	struct action_data *data;
	int ret = -EINVAL;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return ERR_PTR(-ENOMEM);

	match_event = strsep(&str, ")");
	if (!match_event || !str) {
		hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(match_event));
		goto free;
	}

	match_event_system = strsep(&match_event, ".");
	if (!match_event) {
		hist_err(tr, HIST_ERR_SUBSYS_NOT_FOUND, errpos(match_event_system));
		goto free;
	}

	if (IS_ERR(event_file(tr, match_event_system, match_event))) {
		hist_err(tr, HIST_ERR_INVALID_SUBSYS_EVENT, errpos(match_event));
		goto free;
	}

	data->match_data.event = kstrdup(match_event, GFP_KERNEL);
	if (!data->match_data.event) {
		ret = -ENOMEM;
		goto free;
	}

	data->match_data.event_system = kstrdup(match_event_system, GFP_KERNEL);
	if (!data->match_data.event_system) {
		ret = -ENOMEM;
		goto free;
	}

	ret = action_parse(tr, str, data, HANDLER_ONMATCH);
	if (ret)
		goto free;
 out:
	return data;
 free:
	onmatch_destroy(data);
	data = ERR_PTR(ret);
	goto out;
}

static int create_hitcount_val(struct hist_trigger_data *hist_data)
{
	hist_data->fields[HITCOUNT_IDX] =
		create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
	if (!hist_data->fields[HITCOUNT_IDX])
		return -ENOMEM;

	hist_data->n_vals++;
	hist_data->n_fields++;

	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
		return -EINVAL;

	return 0;
}

static int __create_val_field(struct hist_trigger_data *hist_data,
			      unsigned int val_idx,
			      struct trace_event_file *file,
			      char *var_name, char *field_str,
			      unsigned long flags)
{
	struct hist_field *hist_field;
	int ret = 0;

	hist_field = parse_expr(hist_data, file, field_str, flags, var_name, 0);
	if (IS_ERR(hist_field)) {
		ret = PTR_ERR(hist_field);
		goto out;
	}

	hist_data->fields[val_idx] = hist_field;

	++hist_data->n_vals;
	++hist_data->n_fields;

	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
		ret = -EINVAL;
 out:
	return ret;
}

static int create_val_field(struct hist_trigger_data *hist_data,
			    unsigned int val_idx,
			    struct trace_event_file *file,
			    char *field_str)
{
	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
		return -EINVAL;

	return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
}

static int create_var_field(struct hist_trigger_data *hist_data,
			    unsigned int val_idx,
			    struct trace_event_file *file,
			    char *var_name, char *expr_str)
{
	struct trace_array *tr = hist_data->event_file->tr;
	unsigned long flags = 0;
	int ret;

	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
		return -EINVAL;

	if (find_var(hist_data, file, var_name) && !hist_data->remove) {
		hist_err(tr, HIST_ERR_DUPLICATE_VAR, errpos(var_name));
		return -EINVAL;
	}

	flags |= HIST_FIELD_FL_VAR;
	hist_data->n_vars++;
	if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
		return -EINVAL;

	ret = __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);

	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
		hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;

	return ret;
}

static int create_val_fields(struct hist_trigger_data *hist_data,
			     struct trace_event_file *file)
{
	char *fields_str, *field_str;
	unsigned int i, j = 1;
	int ret;

	ret = create_hitcount_val(hist_data);
	if (ret)
		goto out;

	fields_str = hist_data->attrs->vals_str;
	if (!fields_str)
		goto out;

	for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
		     j < TRACING_MAP_VALS_MAX; i++) {
		field_str = strsep(&fields_str, ",");
		if (!field_str)
			break;

		if (strcmp(field_str, "hitcount") == 0)
			continue;

		ret = create_val_field(hist_data, j++, file, field_str);
		if (ret)
			goto out;
	}

	if (fields_str && (strcmp(fields_str, "hitcount") != 0))
		ret = -EINVAL;
 out:
	return ret;
}

static int create_key_field(struct hist_trigger_data *hist_data,
			    unsigned int key_idx,
			    unsigned int key_offset,
			    struct trace_event_file *file,
			    char *field_str)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct hist_field *hist_field = NULL;
	unsigned long flags = 0;
	unsigned int key_size;
	int ret = 0;

	if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
		return -EINVAL;

	flags |= HIST_FIELD_FL_KEY;

	if (strcmp(field_str, "stacktrace") == 0) {
		flags |= HIST_FIELD_FL_STACKTRACE;
		key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
		hist_field = create_hist_field(hist_data, NULL, flags, NULL);
	} else {
		hist_field = parse_expr(hist_data, file, field_str, flags,
					NULL, 0);
		if (IS_ERR(hist_field)) {
			ret = PTR_ERR(hist_field);
			goto out;
		}

		if (field_has_hist_vars(hist_field, 0))	{
			hist_err(tr, HIST_ERR_INVALID_REF_KEY, errpos(field_str));
			destroy_hist_field(hist_field, 0);
			ret = -EINVAL;
			goto out;
		}

		key_size = hist_field->size;
	}

	hist_data->fields[key_idx] = hist_field;

	key_size = ALIGN(key_size, sizeof(u64));
	hist_data->fields[key_idx]->size = key_size;
	hist_data->fields[key_idx]->offset = key_offset;

	hist_data->key_size += key_size;

	if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
		ret = -EINVAL;
		goto out;
	}

	hist_data->n_keys++;
	hist_data->n_fields++;

	if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
		return -EINVAL;

	ret = key_size;
 out:
	return ret;
}

static int create_key_fields(struct hist_trigger_data *hist_data,
			     struct trace_event_file *file)
{
	unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
	char *fields_str, *field_str;
	int ret = -EINVAL;

	fields_str = hist_data->attrs->keys_str;
	if (!fields_str)
		goto out;

	for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
		field_str = strsep(&fields_str, ",");
		if (!field_str)
			break;
		ret = create_key_field(hist_data, i, key_offset,
				       file, field_str);
		if (ret < 0)
			goto out;
		key_offset += ret;
	}
	if (fields_str) {
		ret = -EINVAL;
		goto out;
	}
	ret = 0;
 out:
	return ret;
}

static int create_var_fields(struct hist_trigger_data *hist_data,
			     struct trace_event_file *file)
{
	unsigned int i, j = hist_data->n_vals;
	int ret = 0;

	unsigned int n_vars = hist_data->attrs->var_defs.n_vars;

	for (i = 0; i < n_vars; i++) {
		char *var_name = hist_data->attrs->var_defs.name[i];
		char *expr = hist_data->attrs->var_defs.expr[i];

		ret = create_var_field(hist_data, j++, file, var_name, expr);
		if (ret)
			goto out;
	}
 out:
	return ret;
}

static void free_var_defs(struct hist_trigger_data *hist_data)
{
	unsigned int i;

	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
		kfree(hist_data->attrs->var_defs.name[i]);
		kfree(hist_data->attrs->var_defs.expr[i]);
	}

	hist_data->attrs->var_defs.n_vars = 0;
}

static int parse_var_defs(struct hist_trigger_data *hist_data)
{
	struct trace_array *tr = hist_data->event_file->tr;
	char *s, *str, *var_name, *field_str;
	unsigned int i, j, n_vars = 0;
	int ret = 0;

	for (i = 0; i < hist_data->attrs->n_assignments; i++) {
		str = hist_data->attrs->assignment_str[i];
		for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
			field_str = strsep(&str, ",");
			if (!field_str)
				break;

			var_name = strsep(&field_str, "=");
			if (!var_name || !field_str) {
				hist_err(tr, HIST_ERR_MALFORMED_ASSIGNMENT,
					 errpos(var_name));
				ret = -EINVAL;
				goto free;
			}

			if (n_vars == TRACING_MAP_VARS_MAX) {
				hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(var_name));
				ret = -EINVAL;
				goto free;
			}

			s = kstrdup(var_name, GFP_KERNEL);
			if (!s) {
				ret = -ENOMEM;
				goto free;
			}
			hist_data->attrs->var_defs.name[n_vars] = s;

			s = kstrdup(field_str, GFP_KERNEL);
			if (!s) {
				ret = -ENOMEM;
				goto free;
			}
			hist_data->attrs->var_defs.expr[n_vars++] = s;

			hist_data->attrs->var_defs.n_vars = n_vars;
		}
	}

	return ret;
 free:
	free_var_defs(hist_data);

	return ret;
}

static int create_hist_fields(struct hist_trigger_data *hist_data,
			      struct trace_event_file *file)
{
	int ret;

	ret = parse_var_defs(hist_data);
	if (ret)
		goto out;

	ret = create_val_fields(hist_data, file);
	if (ret)
		goto out;

	ret = create_var_fields(hist_data, file);
	if (ret)
		goto out;

	ret = create_key_fields(hist_data, file);
	if (ret)
		goto out;
 out:
	free_var_defs(hist_data);

	return ret;
}

static int is_descending(struct trace_array *tr, const char *str)
{
	if (!str)
		return 0;

	if (strcmp(str, "descending") == 0)
		return 1;

	if (strcmp(str, "ascending") == 0)
		return 0;

	hist_err(tr, HIST_ERR_INVALID_SORT_MODIFIER, errpos((char *)str));

	return -EINVAL;
}

static int create_sort_keys(struct hist_trigger_data *hist_data)
{
	struct trace_array *tr = hist_data->event_file->tr;
	char *fields_str = hist_data->attrs->sort_key_str;
	struct tracing_map_sort_key *sort_key;
	int descending, ret = 0;
	unsigned int i, j, k;

	hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */

	if (!fields_str)
		goto out;

	for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
		struct hist_field *hist_field;
		char *field_str, *field_name;
		const char *test_name;

		sort_key = &hist_data->sort_keys[i];

		field_str = strsep(&fields_str, ",");
		if (!field_str)
			break;

		if (!*field_str) {
			ret = -EINVAL;
			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
			break;
		}

		if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
			hist_err(tr, HIST_ERR_TOO_MANY_SORT_FIELDS, errpos("sort="));
			ret = -EINVAL;
			break;
		}

		field_name = strsep(&field_str, ".");
		if (!field_name || !*field_name) {
			ret = -EINVAL;
			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
			break;
		}

		if (strcmp(field_name, "hitcount") == 0) {
			descending = is_descending(tr, field_str);
			if (descending < 0) {
				ret = descending;
				break;
			}
			sort_key->descending = descending;
			continue;
		}

		for (j = 1, k = 1; j < hist_data->n_fields; j++) {
			unsigned int idx;

			hist_field = hist_data->fields[j];
			if (hist_field->flags & HIST_FIELD_FL_VAR)
				continue;

			idx = k++;

			test_name = hist_field_name(hist_field, 0);

			if (strcmp(field_name, test_name) == 0) {
				sort_key->field_idx = idx;
				descending = is_descending(tr, field_str);
				if (descending < 0) {
					ret = descending;
					goto out;
				}
				sort_key->descending = descending;
				break;
			}
		}
		if (j == hist_data->n_fields) {
			ret = -EINVAL;
			hist_err(tr, HIST_ERR_INVALID_SORT_FIELD, errpos(field_name));
			break;
		}
	}

	hist_data->n_sort_keys = i;
 out:
	return ret;
}

static void destroy_actions(struct hist_trigger_data *hist_data)
{
	unsigned int i;

	for (i = 0; i < hist_data->n_actions; i++) {
		struct action_data *data = hist_data->actions[i];

		if (data->handler == HANDLER_ONMATCH)
			onmatch_destroy(data);
		else if (data->handler == HANDLER_ONMAX ||
			 data->handler == HANDLER_ONCHANGE)
			track_data_destroy(hist_data, data);
		else
			kfree(data);
	}
}

static int parse_actions(struct hist_trigger_data *hist_data)
{
	struct trace_array *tr = hist_data->event_file->tr;
	struct action_data *data;
	unsigned int i;
	int ret = 0;
	char *str;
	int len;

	for (i = 0; i < hist_data->attrs->n_actions; i++) {
		str = hist_data->attrs->action_str[i];

		if ((len = str_has_prefix(str, "onmatch("))) {
			char *action_str = str + len;

			data = onmatch_parse(tr, action_str);
			if (IS_ERR(data)) {
				ret = PTR_ERR(data);
				break;
			}
		} else if ((len = str_has_prefix(str, "onmax("))) {
			char *action_str = str + len;

			data = track_data_parse(hist_data, action_str,
						HANDLER_ONMAX);
			if (IS_ERR(data)) {
				ret = PTR_ERR(data);
				break;
			}
		} else if ((len = str_has_prefix(str, "onchange("))) {
			char *action_str = str + len;

			data = track_data_parse(hist_data, action_str,
						HANDLER_ONCHANGE);
			if (IS_ERR(data)) {
				ret = PTR_ERR(data);
				break;
			}
		} else {
			ret = -EINVAL;
			break;
		}

		hist_data->actions[hist_data->n_actions++] = data;
	}

	return ret;
}

static int create_actions(struct hist_trigger_data *hist_data)
{
	struct action_data *data;
	unsigned int i;
	int ret = 0;

	for (i = 0; i < hist_data->attrs->n_actions; i++) {
		data = hist_data->actions[i];

		if (data->handler == HANDLER_ONMATCH) {
			ret = onmatch_create(hist_data, data);
			if (ret)
				break;
		} else if (data->handler == HANDLER_ONMAX ||
			   data->handler == HANDLER_ONCHANGE) {
			ret = track_data_create(hist_data, data);
			if (ret)
				break;
		} else {
			ret = -EINVAL;
			break;
		}
	}

	return ret;
}

static void print_actions(struct seq_file *m,
			  struct hist_trigger_data *hist_data,
			  struct tracing_map_elt *elt)
{
	unsigned int i;

	for (i = 0; i < hist_data->n_actions; i++) {
		struct action_data *data = hist_data->actions[i];

		if (data->action == ACTION_SNAPSHOT)
			continue;

		if (data->handler == HANDLER_ONMAX ||
		    data->handler == HANDLER_ONCHANGE)
			track_data_print(m, hist_data, elt, data);
	}
}

static void print_action_spec(struct seq_file *m,
			      struct hist_trigger_data *hist_data,
			      struct action_data *data)
{
	unsigned int i;

	if (data->action == ACTION_SAVE) {
		for (i = 0; i < hist_data->n_save_vars; i++) {
			seq_printf(m, "%s", hist_data->save_vars[i]->var->var.name);
			if (i < hist_data->n_save_vars - 1)
				seq_puts(m, ",");
		}
	} else if (data->action == ACTION_TRACE) {
		if (data->use_trace_keyword)
			seq_printf(m, "%s", data->synth_event_name);
		for (i = 0; i < data->n_params; i++) {
			if (i || data->use_trace_keyword)
				seq_puts(m, ",");
			seq_printf(m, "%s", data->params[i]);
		}
	}
}

static void print_track_data_spec(struct seq_file *m,
				  struct hist_trigger_data *hist_data,
				  struct action_data *data)
{
	if (data->handler == HANDLER_ONMAX)
		seq_puts(m, ":onmax(");
	else if (data->handler == HANDLER_ONCHANGE)
		seq_puts(m, ":onchange(");
	seq_printf(m, "%s", data->track_data.var_str);
	seq_printf(m, ").%s(", data->action_name);

	print_action_spec(m, hist_data, data);

	seq_puts(m, ")");
}

static void print_onmatch_spec(struct seq_file *m,
			       struct hist_trigger_data *hist_data,
			       struct action_data *data)
{
	seq_printf(m, ":onmatch(%s.%s).", data->match_data.event_system,
		   data->match_data.event);

	seq_printf(m, "%s(", data->action_name);

	print_action_spec(m, hist_data, data);

	seq_puts(m, ")");
}

static bool actions_match(struct hist_trigger_data *hist_data,
			  struct hist_trigger_data *hist_data_test)
{
	unsigned int i, j;

	if (hist_data->n_actions != hist_data_test->n_actions)
		return false;

	for (i = 0; i < hist_data->n_actions; i++) {
		struct action_data *data = hist_data->actions[i];
		struct action_data *data_test = hist_data_test->actions[i];
		char *action_name, *action_name_test;

		if (data->handler != data_test->handler)
			return false;
		if (data->action != data_test->action)
			return false;

		if (data->n_params != data_test->n_params)
			return false;

		for (j = 0; j < data->n_params; j++) {
			if (strcmp(data->params[j], data_test->params[j]) != 0)
				return false;
		}

		if (data->use_trace_keyword)
			action_name = data->synth_event_name;
		else
			action_name = data->action_name;

		if (data_test->use_trace_keyword)
			action_name_test = data_test->synth_event_name;
		else
			action_name_test = data_test->action_name;

		if (strcmp(action_name, action_name_test) != 0)
			return false;

		if (data->handler == HANDLER_ONMATCH) {
			if (strcmp(data->match_data.event_system,
				   data_test->match_data.event_system) != 0)
				return false;
			if (strcmp(data->match_data.event,
				   data_test->match_data.event) != 0)
				return false;
		} else if (data->handler == HANDLER_ONMAX ||
			   data->handler == HANDLER_ONCHANGE) {
			if (strcmp(data->track_data.var_str,
				   data_test->track_data.var_str) != 0)
				return false;
		}
	}

	return true;
}


static void print_actions_spec(struct seq_file *m,
			       struct hist_trigger_data *hist_data)
{
	unsigned int i;

	for (i = 0; i < hist_data->n_actions; i++) {
		struct action_data *data = hist_data->actions[i];

		if (data->handler == HANDLER_ONMATCH)
			print_onmatch_spec(m, hist_data, data);
		else if (data->handler == HANDLER_ONMAX ||
			 data->handler == HANDLER_ONCHANGE)
			print_track_data_spec(m, hist_data, data);
	}
}

static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
{
	unsigned int i;

	for (i = 0; i < hist_data->n_field_var_hists; i++) {
		kfree(hist_data->field_var_hists[i]->cmd);
		kfree(hist_data->field_var_hists[i]);
	}
}

static void destroy_hist_data(struct hist_trigger_data *hist_data)
{
	if (!hist_data)
		return;

	destroy_hist_trigger_attrs(hist_data->attrs);
	destroy_hist_fields(hist_data);
	tracing_map_destroy(hist_data->map);

	destroy_actions(hist_data);
	destroy_field_vars(hist_data);
	destroy_field_var_hists(hist_data);

	kfree(hist_data);
}

static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
{
	struct tracing_map *map = hist_data->map;
	struct ftrace_event_field *field;
	struct hist_field *hist_field;
	int i, idx = 0;

	for_each_hist_field(i, hist_data) {
		hist_field = hist_data->fields[i];
		if (hist_field->flags & HIST_FIELD_FL_KEY) {
			tracing_map_cmp_fn_t cmp_fn;

			field = hist_field->field;

			if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
				cmp_fn = tracing_map_cmp_none;
			else if (!field)
				cmp_fn = tracing_map_cmp_num(hist_field->size,
							     hist_field->is_signed);
			else if (is_string_field(field))
				cmp_fn = tracing_map_cmp_string;
			else
				cmp_fn = tracing_map_cmp_num(field->size,
							     field->is_signed);
			idx = tracing_map_add_key_field(map,
							hist_field->offset,
							cmp_fn);
		} else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
			idx = tracing_map_add_sum_field(map);

		if (idx < 0)
			return idx;

		if (hist_field->flags & HIST_FIELD_FL_VAR) {
			idx = tracing_map_add_var(map);
			if (idx < 0)
				return idx;
			hist_field->var.idx = idx;
			hist_field->var.hist_data = hist_data;
		}
	}

	return 0;
}

static struct hist_trigger_data *
create_hist_data(unsigned int map_bits,
		 struct hist_trigger_attrs *attrs,
		 struct trace_event_file *file,
		 bool remove)
{
	const struct tracing_map_ops *map_ops = NULL;
	struct hist_trigger_data *hist_data;
	int ret = 0;

	hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
	if (!hist_data)
		return ERR_PTR(-ENOMEM);

	hist_data->attrs = attrs;
	hist_data->remove = remove;
	hist_data->event_file = file;

	ret = parse_actions(hist_data);
	if (ret)
		goto free;

	ret = create_hist_fields(hist_data, file);
	if (ret)
		goto free;

	ret = create_sort_keys(hist_data);
	if (ret)
		goto free;

	map_ops = &hist_trigger_elt_data_ops;

	hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
					    map_ops, hist_data);
	if (IS_ERR(hist_data->map)) {
		ret = PTR_ERR(hist_data->map);
		hist_data->map = NULL;
		goto free;
	}

	ret = create_tracing_map_fields(hist_data);
	if (ret)
		goto free;
 out:
	return hist_data;
 free:
	hist_data->attrs = NULL;

	destroy_hist_data(hist_data);

	hist_data = ERR_PTR(ret);

	goto out;
}

static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
				    struct tracing_map_elt *elt, void *rec,
				    struct ring_buffer_event *rbe,
				    u64 *var_ref_vals)
{
	struct hist_elt_data *elt_data;
	struct hist_field *hist_field;
	unsigned int i, var_idx;
	u64 hist_val;

	elt_data = elt->private_data;
	elt_data->var_ref_vals = var_ref_vals;

	for_each_hist_val_field(i, hist_data) {
		hist_field = hist_data->fields[i];
		hist_val = hist_field->fn(hist_field, elt, rbe, rec);
		if (hist_field->flags & HIST_FIELD_FL_VAR) {
			var_idx = hist_field->var.idx;

			if (hist_field->flags & HIST_FIELD_FL_STRING) {
				unsigned int str_start, var_str_idx, idx;
				char *str, *val_str;

				str_start = hist_data->n_field_var_str +
					hist_data->n_save_var_str;
				var_str_idx = hist_field->var_str_idx;
				idx = str_start + var_str_idx;

				str = elt_data->field_var_str[idx];
				val_str = (char *)(uintptr_t)hist_val;
				strscpy(str, val_str, STR_VAR_LEN_MAX);

				hist_val = (u64)(uintptr_t)str;
			}
			tracing_map_set_var(elt, var_idx, hist_val);
			continue;
		}
		tracing_map_update_sum(elt, i, hist_val);
	}

	for_each_hist_key_field(i, hist_data) {
		hist_field = hist_data->fields[i];
		if (hist_field->flags & HIST_FIELD_FL_VAR) {
			hist_val = hist_field->fn(hist_field, elt, rbe, rec);
			var_idx = hist_field->var.idx;
			tracing_map_set_var(elt, var_idx, hist_val);
		}
	}

	update_field_vars(hist_data, elt, rbe, rec);
}

static inline void add_to_key(char *compound_key, void *key,
			      struct hist_field *key_field, void *rec)
{
	size_t size = key_field->size;

	if (key_field->flags & HIST_FIELD_FL_STRING) {
		struct ftrace_event_field *field;

		field = key_field->field;
		if (field->filter_type == FILTER_DYN_STRING)
			size = *(u32 *)(rec + field->offset) >> 16;
		else if (field->filter_type == FILTER_PTR_STRING)
			size = strlen(key);
		else if (field->filter_type == FILTER_STATIC_STRING)
			size = field->size;

		/* ensure NULL-termination */
		if (size > key_field->size - 1)
			size = key_field->size - 1;

		strncpy(compound_key + key_field->offset, (char *)key, size);
	} else
		memcpy(compound_key + key_field->offset, key, size);
}

static void
hist_trigger_actions(struct hist_trigger_data *hist_data,
		     struct tracing_map_elt *elt, void *rec,
		     struct ring_buffer_event *rbe, void *key,
		     u64 *var_ref_vals)
{
	struct action_data *data;
	unsigned int i;

	for (i = 0; i < hist_data->n_actions; i++) {
		data = hist_data->actions[i];
		data->fn(hist_data, elt, rec, rbe, key, data, var_ref_vals);
	}
}

static void event_hist_trigger(struct event_trigger_data *data, void *rec,
			       struct ring_buffer_event *rbe)
{
	struct hist_trigger_data *hist_data = data->private_data;
	bool use_compound_key = (hist_data->n_keys > 1);
	unsigned long entries[HIST_STACKTRACE_DEPTH];
	u64 var_ref_vals[TRACING_MAP_VARS_MAX];
	char compound_key[HIST_KEY_SIZE_MAX];
	struct tracing_map_elt *elt = NULL;
	struct hist_field *key_field;
	u64 field_contents;
	void *key = NULL;
	unsigned int i;

	memset(compound_key, 0, hist_data->key_size);

	for_each_hist_key_field(i, hist_data) {
		key_field = hist_data->fields[i];

		if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
			memset(entries, 0, HIST_STACKTRACE_SIZE);
			stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
					 HIST_STACKTRACE_SKIP);
			key = entries;
		} else {
			field_contents = key_field->fn(key_field, elt, rbe, rec);
			if (key_field->flags & HIST_FIELD_FL_STRING) {
				key = (void *)(unsigned long)field_contents;
				use_compound_key = true;
			} else
				key = (void *)&field_contents;
		}

		if (use_compound_key)
			add_to_key(compound_key, key, key_field, rec);
	}

	if (use_compound_key)
		key = compound_key;

	if (hist_data->n_var_refs &&
	    !resolve_var_refs(hist_data, key, var_ref_vals, false))
		return;

	elt = tracing_map_insert(hist_data->map, key);
	if (!elt)
		return;

	hist_trigger_elt_update(hist_data, elt, rec, rbe, var_ref_vals);

	if (resolve_var_refs(hist_data, key, var_ref_vals, true))
		hist_trigger_actions(hist_data, elt, rec, rbe, key, var_ref_vals);
}

static void hist_trigger_stacktrace_print(struct seq_file *m,
					  unsigned long *stacktrace_entries,
					  unsigned int max_entries)
{
	char str[KSYM_SYMBOL_LEN];
	unsigned int spaces = 8;
	unsigned int i;

	for (i = 0; i < max_entries; i++) {
		if (!stacktrace_entries[i])
			return;

		seq_printf(m, "%*c", 1 + spaces, ' ');
		sprint_symbol(str, stacktrace_entries[i]);
		seq_printf(m, "%s\n", str);
	}
}

static void hist_trigger_print_key(struct seq_file *m,
				   struct hist_trigger_data *hist_data,
				   void *key,
				   struct tracing_map_elt *elt)
{
	struct hist_field *key_field;
	char str[KSYM_SYMBOL_LEN];
	bool multiline = false;
	const char *field_name;
	unsigned int i;
	u64 uval;

	seq_puts(m, "{ ");

	for_each_hist_key_field(i, hist_data) {
		key_field = hist_data->fields[i];

		if (i > hist_data->n_vals)
			seq_puts(m, ", ");

		field_name = hist_field_name(key_field, 0);

		if (key_field->flags & HIST_FIELD_FL_HEX) {
			uval = *(u64 *)(key + key_field->offset);
			seq_printf(m, "%s: %llx", field_name, uval);
		} else if (key_field->flags & HIST_FIELD_FL_SYM) {
			uval = *(u64 *)(key + key_field->offset);
			sprint_symbol_no_offset(str, uval);
			seq_printf(m, "%s: [%llx] %-45s", field_name,
				   uval, str);
		} else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
			uval = *(u64 *)(key + key_field->offset);
			sprint_symbol(str, uval);
			seq_printf(m, "%s: [%llx] %-55s", field_name,
				   uval, str);
		} else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
			struct hist_elt_data *elt_data = elt->private_data;
			char *comm;

			if (WARN_ON_ONCE(!elt_data))
				return;

			comm = elt_data->comm;

			uval = *(u64 *)(key + key_field->offset);
			seq_printf(m, "%s: %-16s[%10llu]", field_name,
				   comm, uval);
		} else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
			const char *syscall_name;

			uval = *(u64 *)(key + key_field->offset);
			syscall_name = get_syscall_name(uval);
			if (!syscall_name)
				syscall_name = "unknown_syscall";

			seq_printf(m, "%s: %-30s[%3llu]", field_name,
				   syscall_name, uval);
		} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
			seq_puts(m, "stacktrace:\n");
			hist_trigger_stacktrace_print(m,
						      key + key_field->offset,
						      HIST_STACKTRACE_DEPTH);
			multiline = true;
		} else if (key_field->flags & HIST_FIELD_FL_LOG2) {
			seq_printf(m, "%s: ~ 2^%-2llu", field_name,
				   *(u64 *)(key + key_field->offset));
		} else if (key_field->flags & HIST_FIELD_FL_STRING) {
			seq_printf(m, "%s: %-50s", field_name,
				   (char *)(key + key_field->offset));
		} else {
			uval = *(u64 *)(key + key_field->offset);
			seq_printf(m, "%s: %10llu", field_name, uval);
		}
	}

	if (!multiline)
		seq_puts(m, " ");

	seq_puts(m, "}");
}

static void hist_trigger_entry_print(struct seq_file *m,
				     struct hist_trigger_data *hist_data,
				     void *key,
				     struct tracing_map_elt *elt)
{
	const char *field_name;
	unsigned int i;

	hist_trigger_print_key(m, hist_data, key, elt);

	seq_printf(m, " hitcount: %10llu",
		   tracing_map_read_sum(elt, HITCOUNT_IDX));

	for (i = 1; i < hist_data->n_vals; i++) {
		field_name = hist_field_name(hist_data->fields[i], 0);

		if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR ||
		    hist_data->fields[i]->flags & HIST_FIELD_FL_EXPR)
			continue;

		if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
			seq_printf(m, "  %s: %10llx", field_name,
				   tracing_map_read_sum(elt, i));
		} else {
			seq_printf(m, "  %s: %10llu", field_name,
				   tracing_map_read_sum(elt, i));
		}
	}

	print_actions(m, hist_data, elt);

	seq_puts(m, "\n");
}

static int print_entries(struct seq_file *m,
			 struct hist_trigger_data *hist_data)
{
	struct tracing_map_sort_entry **sort_entries = NULL;
	struct tracing_map *map = hist_data->map;
	int i, n_entries;

	n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
					     hist_data->n_sort_keys,
					     &sort_entries);
	if (n_entries < 0)
		return n_entries;

	for (i = 0; i < n_entries; i++)
		hist_trigger_entry_print(m, hist_data,
					 sort_entries[i]->key,
					 sort_entries[i]->elt);

	tracing_map_destroy_sort_entries(sort_entries, n_entries);

	return n_entries;
}

static void hist_trigger_show(struct seq_file *m,
			      struct event_trigger_data *data, int n)
{
	struct hist_trigger_data *hist_data;
	int n_entries;

	if (n > 0)
		seq_puts(m, "\n\n");

	seq_puts(m, "# event histogram\n#\n# trigger info: ");
	data->ops->print(m, data->ops, data);
	seq_puts(m, "#\n\n");

	hist_data = data->private_data;
	n_entries = print_entries(m, hist_data);
	if (n_entries < 0)
		n_entries = 0;

	track_data_snapshot_print(m, hist_data);

	seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
		   (u64)atomic64_read(&hist_data->map->hits),
		   n_entries, (u64)atomic64_read(&hist_data->map->drops));
}

static int hist_show(struct seq_file *m, void *v)
{
	struct event_trigger_data *data;
	struct trace_event_file *event_file;
	int n = 0, ret = 0;

	mutex_lock(&event_mutex);

	event_file = event_file_data(m->private);
	if (unlikely(!event_file)) {
		ret = -ENODEV;
		goto out_unlock;
	}

	list_for_each_entry(data, &event_file->triggers, list) {
		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
			hist_trigger_show(m, data, n++);
	}

 out_unlock:
	mutex_unlock(&event_mutex);

	return ret;
}

static int event_hist_open(struct inode *inode, struct file *file)
{
	int ret;

	ret = security_locked_down(LOCKDOWN_TRACEFS);
	if (ret)
		return ret;

	return single_open(file, hist_show, file);
}

const struct file_operations event_hist_fops = {
	.open = event_hist_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

#ifdef CONFIG_HIST_TRIGGERS_DEBUG
static void hist_field_debug_show_flags(struct seq_file *m,
					unsigned long flags)
{
	seq_puts(m, "      flags:\n");

	if (flags & HIST_FIELD_FL_KEY)
		seq_puts(m, "        HIST_FIELD_FL_KEY\n");
	else if (flags & HIST_FIELD_FL_HITCOUNT)
		seq_puts(m, "        VAL: HIST_FIELD_FL_HITCOUNT\n");
	else if (flags & HIST_FIELD_FL_VAR)
		seq_puts(m, "        HIST_FIELD_FL_VAR\n");
	else if (flags & HIST_FIELD_FL_VAR_REF)
		seq_puts(m, "        HIST_FIELD_FL_VAR_REF\n");
	else
		seq_puts(m, "        VAL: normal u64 value\n");

	if (flags & HIST_FIELD_FL_ALIAS)
		seq_puts(m, "        HIST_FIELD_FL_ALIAS\n");
}

static int hist_field_debug_show(struct seq_file *m,
				 struct hist_field *field, unsigned long flags)
{
	if ((field->flags & flags) != flags) {
		seq_printf(m, "ERROR: bad flags - %lx\n", flags);
		return -EINVAL;
	}

	hist_field_debug_show_flags(m, field->flags);
	if (field->field)
		seq_printf(m, "      ftrace_event_field name: %s\n",
			   field->field->name);

	if (field->flags & HIST_FIELD_FL_VAR) {
		seq_printf(m, "      var.name: %s\n", field->var.name);
		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
			   field->var.idx);
	}

	if (field->flags & HIST_FIELD_FL_ALIAS)
		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
			   field->var_ref_idx);

	if (field->flags & HIST_FIELD_FL_VAR_REF) {
		seq_printf(m, "      name: %s\n", field->name);
		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
			   field->var.idx);
		seq_printf(m, "      var.hist_data: %p\n", field->var.hist_data);
		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
			   field->var_ref_idx);
		if (field->system)
			seq_printf(m, "      system: %s\n", field->system);
		if (field->event_name)
			seq_printf(m, "      event_name: %s\n", field->event_name);
	}

	seq_printf(m, "      type: %s\n", field->type);
	seq_printf(m, "      size: %u\n", field->size);
	seq_printf(m, "      is_signed: %u\n", field->is_signed);

	return 0;
}

static int field_var_debug_show(struct seq_file *m,
				struct field_var *field_var, unsigned int i,
				bool save_vars)
{
	const char *vars_name = save_vars ? "save_vars" : "field_vars";
	struct hist_field *field;
	int ret = 0;

	seq_printf(m, "\n    hist_data->%s[%d]:\n", vars_name, i);

	field = field_var->var;

	seq_printf(m, "\n      %s[%d].var:\n", vars_name, i);

	hist_field_debug_show_flags(m, field->flags);
	seq_printf(m, "      var.name: %s\n", field->var.name);
	seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
		   field->var.idx);

	field = field_var->val;

	seq_printf(m, "\n      %s[%d].val:\n", vars_name, i);
	if (field->field)
		seq_printf(m, "      ftrace_event_field name: %s\n",
			   field->field->name);
	else {
		ret = -EINVAL;
		goto out;
	}

	seq_printf(m, "      type: %s\n", field->type);
	seq_printf(m, "      size: %u\n", field->size);
	seq_printf(m, "      is_signed: %u\n", field->is_signed);
out:
	return ret;
}

static int hist_action_debug_show(struct seq_file *m,
				  struct action_data *data, int i)
{
	int ret = 0;

	if (data->handler == HANDLER_ONMAX ||
	    data->handler == HANDLER_ONCHANGE) {
		seq_printf(m, "\n    hist_data->actions[%d].track_data.var_ref:\n", i);
		ret = hist_field_debug_show(m, data->track_data.var_ref,
					    HIST_FIELD_FL_VAR_REF);
		if (ret)
			goto out;

		seq_printf(m, "\n    hist_data->actions[%d].track_data.track_var:\n", i);
		ret = hist_field_debug_show(m, data->track_data.track_var,
					    HIST_FIELD_FL_VAR);
		if (ret)
			goto out;
	}

	if (data->handler == HANDLER_ONMATCH) {
		seq_printf(m, "\n    hist_data->actions[%d].match_data.event_system: %s\n",
			   i, data->match_data.event_system);
		seq_printf(m, "    hist_data->actions[%d].match_data.event: %s\n",
			   i, data->match_data.event);
	}
out:
	return ret;
}

static int hist_actions_debug_show(struct seq_file *m,
				   struct hist_trigger_data *hist_data)
{
	int i, ret = 0;

	if (hist_data->n_actions)
		seq_puts(m, "\n  action tracking variables (for onmax()/onchange()/onmatch()):\n");

	for (i = 0; i < hist_data->n_actions; i++) {
		struct action_data *action = hist_data->actions[i];

		ret = hist_action_debug_show(m, action, i);
		if (ret)
			goto out;
	}

	if (hist_data->n_save_vars)
		seq_puts(m, "\n  save action variables (save() params):\n");

	for (i = 0; i < hist_data->n_save_vars; i++) {
		ret = field_var_debug_show(m, hist_data->save_vars[i], i, true);
		if (ret)
			goto out;
	}
out:
	return ret;
}

static void hist_trigger_debug_show(struct seq_file *m,
				    struct event_trigger_data *data, int n)
{
	struct hist_trigger_data *hist_data;
	int i, ret;

	if (n > 0)
		seq_puts(m, "\n\n");

	seq_puts(m, "# event histogram\n#\n# trigger info: ");
	data->ops->print(m, data->ops, data);
	seq_puts(m, "#\n\n");

	hist_data = data->private_data;

	seq_printf(m, "hist_data: %p\n\n", hist_data);
	seq_printf(m, "  n_vals: %u\n", hist_data->n_vals);
	seq_printf(m, "  n_keys: %u\n", hist_data->n_keys);
	seq_printf(m, "  n_fields: %u\n", hist_data->n_fields);

	seq_puts(m, "\n  val fields:\n\n");

	seq_puts(m, "    hist_data->fields[0]:\n");
	ret = hist_field_debug_show(m, hist_data->fields[0],
				    HIST_FIELD_FL_HITCOUNT);
	if (ret)
		return;

	for (i = 1; i < hist_data->n_vals; i++) {
		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
		ret = hist_field_debug_show(m, hist_data->fields[i], 0);
		if (ret)
			return;
	}

	seq_puts(m, "\n  key fields:\n");

	for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
		ret = hist_field_debug_show(m, hist_data->fields[i],
					    HIST_FIELD_FL_KEY);
		if (ret)
			return;
	}

	if (hist_data->n_var_refs)
		seq_puts(m, "\n  variable reference fields:\n");

	for (i = 0; i < hist_data->n_var_refs; i++) {
		seq_printf(m, "\n    hist_data->var_refs[%d]:\n", i);
		ret = hist_field_debug_show(m, hist_data->var_refs[i],
					    HIST_FIELD_FL_VAR_REF);
		if (ret)
			return;
	}

	if (hist_data->n_field_vars)
		seq_puts(m, "\n  field variables:\n");

	for (i = 0; i < hist_data->n_field_vars; i++) {
		ret = field_var_debug_show(m, hist_data->field_vars[i], i, false);
		if (ret)
			return;
	}

	ret = hist_actions_debug_show(m, hist_data);
	if (ret)
		return;
}

static int hist_debug_show(struct seq_file *m, void *v)
{
	struct event_trigger_data *data;
	struct trace_event_file *event_file;
	int n = 0, ret = 0;

	mutex_lock(&event_mutex);

	event_file = event_file_data(m->private);
	if (unlikely(!event_file)) {
		ret = -ENODEV;
		goto out_unlock;
	}

	list_for_each_entry(data, &event_file->triggers, list) {
		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
			hist_trigger_debug_show(m, data, n++);
	}

 out_unlock:
	mutex_unlock(&event_mutex);

	return ret;
}

static int event_hist_debug_open(struct inode *inode, struct file *file)
{
	int ret;

	ret = security_locked_down(LOCKDOWN_TRACEFS);
	if (ret)
		return ret;

	return single_open(file, hist_debug_show, file);
}

const struct file_operations event_hist_debug_fops = {
	.open = event_hist_debug_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};
#endif

static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
{
	const char *field_name = hist_field_name(hist_field, 0);

	if (hist_field->var.name)
		seq_printf(m, "%s=", hist_field->var.name);

	if (hist_field->flags & HIST_FIELD_FL_CPU)
		seq_puts(m, "cpu");
	else if (field_name) {
		if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
		    hist_field->flags & HIST_FIELD_FL_ALIAS)
			seq_putc(m, '$');
		seq_printf(m, "%s", field_name);
	} else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
		seq_puts(m, "common_timestamp");

	if (hist_field->flags) {
		if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
		    !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
			const char *flags = get_hist_field_flags(hist_field);

			if (flags)
				seq_printf(m, ".%s", flags);
		}
	}
}

static int event_hist_trigger_print(struct seq_file *m,
				    struct event_trigger_ops *ops,
				    struct event_trigger_data *data)
{
	struct hist_trigger_data *hist_data = data->private_data;
	struct hist_field *field;
	bool have_var = false;
	unsigned int i;

	seq_puts(m, "hist:");

	if (data->name)
		seq_printf(m, "%s:", data->name);

	seq_puts(m, "keys=");

	for_each_hist_key_field(i, hist_data) {
		field = hist_data->fields[i];

		if (i > hist_data->n_vals)
			seq_puts(m, ",");

		if (field->flags & HIST_FIELD_FL_STACKTRACE)
			seq_puts(m, "stacktrace");
		else
			hist_field_print(m, field);
	}

	seq_puts(m, ":vals=");

	for_each_hist_val_field(i, hist_data) {
		field = hist_data->fields[i];
		if (field->flags & HIST_FIELD_FL_VAR) {
			have_var = true;
			continue;
		}

		if (i == HITCOUNT_IDX)
			seq_puts(m, "hitcount");
		else {
			seq_puts(m, ",");
			hist_field_print(m, field);
		}
	}

	if (have_var) {
		unsigned int n = 0;

		seq_puts(m, ":");

		for_each_hist_val_field(i, hist_data) {
			field = hist_data->fields[i];

			if (field->flags & HIST_FIELD_FL_VAR) {
				if (n++)
					seq_puts(m, ",");
				hist_field_print(m, field);
			}
		}
	}

	seq_puts(m, ":sort=");

	for (i = 0; i < hist_data->n_sort_keys; i++) {
		struct tracing_map_sort_key *sort_key;
		unsigned int idx, first_key_idx;

		/* skip VAR vals */
		first_key_idx = hist_data->n_vals - hist_data->n_vars;

		sort_key = &hist_data->sort_keys[i];
		idx = sort_key->field_idx;

		if (WARN_ON(idx >= HIST_FIELDS_MAX))
			return -EINVAL;

		if (i > 0)
			seq_puts(m, ",");

		if (idx == HITCOUNT_IDX)
			seq_puts(m, "hitcount");
		else {
			if (idx >= first_key_idx)
				idx += hist_data->n_vars;
			hist_field_print(m, hist_data->fields[idx]);
		}

		if (sort_key->descending)
			seq_puts(m, ".descending");
	}
	seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
	if (hist_data->enable_timestamps)
		seq_printf(m, ":clock=%s", hist_data->attrs->clock);

	print_actions_spec(m, hist_data);

	if (data->filter_str)
		seq_printf(m, " if %s", data->filter_str);

	if (data->paused)
		seq_puts(m, " [paused]");
	else
		seq_puts(m, " [active]");

	seq_putc(m, '\n');

	return 0;
}

static int event_hist_trigger_init(struct event_trigger_ops *ops,
				   struct event_trigger_data *data)
{
	struct hist_trigger_data *hist_data = data->private_data;

	if (!data->ref && hist_data->attrs->name)
		save_named_trigger(hist_data->attrs->name, data);

	data->ref++;

	return 0;
}

static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
{
	struct trace_event_file *file;
	unsigned int i;
	char *cmd;
	int ret;

	for (i = 0; i < hist_data->n_field_var_hists; i++) {
		file = hist_data->field_var_hists[i]->hist_data->event_file;
		cmd = hist_data->field_var_hists[i]->cmd;
		ret = event_hist_trigger_func(&trigger_hist_cmd, file,
					      "!hist", "hist", cmd);
	}
}

static void event_hist_trigger_free(struct event_trigger_ops *ops,
				    struct event_trigger_data *data)
{
	struct hist_trigger_data *hist_data = data->private_data;

	if (WARN_ON_ONCE(data->ref <= 0))
		return;

	data->ref--;
	if (!data->ref) {
		if (data->name)
			del_named_trigger(data);

		trigger_data_free(data);

		remove_hist_vars(hist_data);

		unregister_field_var_hists(hist_data);

		destroy_hist_data(hist_data);
	}
}

static struct event_trigger_ops event_hist_trigger_ops = {
	.func			= event_hist_trigger,
	.print			= event_hist_trigger_print,
	.init			= event_hist_trigger_init,
	.free			= event_hist_trigger_free,
};

static int event_hist_trigger_named_init(struct event_trigger_ops *ops,
					 struct event_trigger_data *data)
{
	data->ref++;

	save_named_trigger(data->named_data->name, data);

	event_hist_trigger_init(ops, data->named_data);

	return 0;
}

static void event_hist_trigger_named_free(struct event_trigger_ops *ops,
					  struct event_trigger_data *data)
{
	if (WARN_ON_ONCE(data->ref <= 0))
		return;

	event_hist_trigger_free(ops, data->named_data);

	data->ref--;
	if (!data->ref) {
		del_named_trigger(data);
		trigger_data_free(data);
	}
}

static struct event_trigger_ops event_hist_trigger_named_ops = {
	.func			= event_hist_trigger,
	.print			= event_hist_trigger_print,
	.init			= event_hist_trigger_named_init,
	.free			= event_hist_trigger_named_free,
};

static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
							    char *param)
{
	return &event_hist_trigger_ops;
}

static void hist_clear(struct event_trigger_data *data)
{
	struct hist_trigger_data *hist_data = data->private_data;

	if (data->name)
		pause_named_trigger(data);

	tracepoint_synchronize_unregister();

	tracing_map_clear(hist_data->map);

	if (data->name)
		unpause_named_trigger(data);
}

static bool compatible_field(struct ftrace_event_field *field,
			     struct ftrace_event_field *test_field)
{
	if (field == test_field)
		return true;
	if (field == NULL || test_field == NULL)
		return false;
	if (strcmp(field->name, test_field->name) != 0)
		return false;
	if (strcmp(field->type, test_field->type) != 0)
		return false;
	if (field->size != test_field->size)
		return false;
	if (field->is_signed != test_field->is_signed)
		return false;

	return true;
}

static bool hist_trigger_match(struct event_trigger_data *data,
			       struct event_trigger_data *data_test,
			       struct event_trigger_data *named_data,
			       bool ignore_filter)
{
	struct tracing_map_sort_key *sort_key, *sort_key_test;
	struct hist_trigger_data *hist_data, *hist_data_test;
	struct hist_field *key_field, *key_field_test;
	unsigned int i;

	if (named_data && (named_data != data_test) &&
	    (named_data != data_test->named_data))
		return false;

	if (!named_data && is_named_trigger(data_test))
		return false;

	hist_data = data->private_data;
	hist_data_test = data_test->private_data;

	if (hist_data->n_vals != hist_data_test->n_vals ||
	    hist_data->n_fields != hist_data_test->n_fields ||
	    hist_data->n_sort_keys != hist_data_test->n_sort_keys)
		return false;

	if (!ignore_filter) {
		if ((data->filter_str && !data_test->filter_str) ||
		   (!data->filter_str && data_test->filter_str))
			return false;
	}

	for_each_hist_field(i, hist_data) {
		key_field = hist_data->fields[i];
		key_field_test = hist_data_test->fields[i];

		if (key_field->flags != key_field_test->flags)
			return false;
		if (!compatible_field(key_field->field, key_field_test->field))
			return false;
		if (key_field->offset != key_field_test->offset)
			return false;
		if (key_field->size != key_field_test->size)
			return false;
		if (key_field->is_signed != key_field_test->is_signed)
			return false;
		if (!!key_field->var.name != !!key_field_test->var.name)
			return false;
		if (key_field->var.name &&
		    strcmp(key_field->var.name, key_field_test->var.name) != 0)
			return false;
	}

	for (i = 0; i < hist_data->n_sort_keys; i++) {
		sort_key = &hist_data->sort_keys[i];
		sort_key_test = &hist_data_test->sort_keys[i];

		if (sort_key->field_idx != sort_key_test->field_idx ||
		    sort_key->descending != sort_key_test->descending)
			return false;
	}

	if (!ignore_filter && data->filter_str &&
	    (strcmp(data->filter_str, data_test->filter_str) != 0))
		return false;

	if (!actions_match(hist_data, hist_data_test))
		return false;

	return true;
}

static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
				 struct event_trigger_data *data,
				 struct trace_event_file *file)
{
	struct hist_trigger_data *hist_data = data->private_data;
	struct event_trigger_data *test, *named_data = NULL;
	struct trace_array *tr = file->tr;
	int ret = 0;

	if (hist_data->attrs->name) {
		named_data = find_named_trigger(hist_data->attrs->name);
		if (named_data) {
			if (!hist_trigger_match(data, named_data, named_data,
						true)) {
				hist_err(tr, HIST_ERR_NAMED_MISMATCH, errpos(hist_data->attrs->name));
				ret = -EINVAL;
				goto out;
			}
		}
	}

	if (hist_data->attrs->name && !named_data)
		goto new;

	lockdep_assert_held(&event_mutex);

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			if (!hist_trigger_match(data, test, named_data, false))
				continue;
			if (hist_data->attrs->pause)
				test->paused = true;
			else if (hist_data->attrs->cont)
				test->paused = false;
			else if (hist_data->attrs->clear)
				hist_clear(test);
			else {
				hist_err(tr, HIST_ERR_TRIGGER_EEXIST, 0);
				ret = -EEXIST;
			}
			goto out;
		}
	}
 new:
	if (hist_data->attrs->cont || hist_data->attrs->clear) {
		hist_err(tr, HIST_ERR_TRIGGER_ENOENT_CLEAR, 0);
		ret = -ENOENT;
		goto out;
	}

	if (hist_data->attrs->pause)
		data->paused = true;

	if (named_data) {
		data->private_data = named_data->private_data;
		set_named_trigger_data(data, named_data);
		data->ops = &event_hist_trigger_named_ops;
	}

	if (data->ops->init) {
		ret = data->ops->init(data->ops, data);
		if (ret < 0)
			goto out;
	}

	if (hist_data->enable_timestamps) {
		char *clock = hist_data->attrs->clock;

		ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
		if (ret) {
			hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
			goto out;
		}

		tracing_set_time_stamp_abs(file->tr, true);
	}

	if (named_data)
		destroy_hist_data(hist_data);

	ret++;
 out:
	return ret;
}

static int hist_trigger_enable(struct event_trigger_data *data,
			       struct trace_event_file *file)
{
	int ret = 0;

	list_add_tail_rcu(&data->list, &file->triggers);

	update_cond_flag(file);

	if (trace_event_trigger_enable_disable(file, 1) < 0) {
		list_del_rcu(&data->list);
		update_cond_flag(file);
		ret--;
	}

	return ret;
}

static bool have_hist_trigger_match(struct event_trigger_data *data,
				    struct trace_event_file *file)
{
	struct hist_trigger_data *hist_data = data->private_data;
	struct event_trigger_data *test, *named_data = NULL;
	bool match = false;

	lockdep_assert_held(&event_mutex);

	if (hist_data->attrs->name)
		named_data = find_named_trigger(hist_data->attrs->name);

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			if (hist_trigger_match(data, test, named_data, false)) {
				match = true;
				break;
			}
		}
	}

	return match;
}

static bool hist_trigger_check_refs(struct event_trigger_data *data,
				    struct trace_event_file *file)
{
	struct hist_trigger_data *hist_data = data->private_data;
	struct event_trigger_data *test, *named_data = NULL;

	lockdep_assert_held(&event_mutex);

	if (hist_data->attrs->name)
		named_data = find_named_trigger(hist_data->attrs->name);

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			if (!hist_trigger_match(data, test, named_data, false))
				continue;
			hist_data = test->private_data;
			if (check_var_refs(hist_data))
				return true;
			break;
		}
	}

	return false;
}

static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops,
				    struct event_trigger_data *data,
				    struct trace_event_file *file)
{
	struct hist_trigger_data *hist_data = data->private_data;
	struct event_trigger_data *test, *named_data = NULL;
	bool unregistered = false;

	lockdep_assert_held(&event_mutex);

	if (hist_data->attrs->name)
		named_data = find_named_trigger(hist_data->attrs->name);

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			if (!hist_trigger_match(data, test, named_data, false))
				continue;
			unregistered = true;
			list_del_rcu(&test->list);
			trace_event_trigger_enable_disable(file, 0);
			update_cond_flag(file);
			break;
		}
	}

	if (unregistered && test->ops->free)
		test->ops->free(test->ops, test);

	if (hist_data->enable_timestamps) {
		if (!hist_data->remove || unregistered)
			tracing_set_time_stamp_abs(file->tr, false);
	}
}

static bool hist_file_check_refs(struct trace_event_file *file)
{
	struct hist_trigger_data *hist_data;
	struct event_trigger_data *test;

	lockdep_assert_held(&event_mutex);

	list_for_each_entry(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			hist_data = test->private_data;
			if (check_var_refs(hist_data))
				return true;
		}
	}

	return false;
}

static void hist_unreg_all(struct trace_event_file *file)
{
	struct event_trigger_data *test, *n;
	struct hist_trigger_data *hist_data;
	struct synth_event *se;
	const char *se_name;

	lockdep_assert_held(&event_mutex);

	if (hist_file_check_refs(file))
		return;

	list_for_each_entry_safe(test, n, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			hist_data = test->private_data;
			list_del_rcu(&test->list);
			trace_event_trigger_enable_disable(file, 0);

			se_name = trace_event_name(file->event_call);
			se = find_synth_event(se_name);
			if (se)
				se->ref--;

			update_cond_flag(file);
			if (hist_data->enable_timestamps)
				tracing_set_time_stamp_abs(file->tr, false);
			if (test->ops->free)
				test->ops->free(test->ops, test);
		}
	}
}

static int event_hist_trigger_func(struct event_command *cmd_ops,
				   struct trace_event_file *file,
				   char *glob, char *cmd, char *param)
{
	unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
	struct event_trigger_data *trigger_data;
	struct hist_trigger_attrs *attrs;
	struct event_trigger_ops *trigger_ops;
	struct hist_trigger_data *hist_data;
	struct synth_event *se;
	const char *se_name;
	bool remove = false;
	char *trigger, *p;
	int ret = 0;

	lockdep_assert_held(&event_mutex);

	if (glob && strlen(glob)) {
		hist_err_clear();
		last_cmd_set(file, param);
	}

	if (!param)
		return -EINVAL;

	if (glob[0] == '!')
		remove = true;

	/*
	 * separate the trigger from the filter (k:v [if filter])
	 * allowing for whitespace in the trigger
	 */
	p = trigger = param;
	do {
		p = strstr(p, "if");
		if (!p)
			break;
		if (p == param)
			return -EINVAL;
		if (*(p - 1) != ' ' && *(p - 1) != '\t') {
			p++;
			continue;
		}
		if (p >= param + strlen(param) - (sizeof("if") - 1) - 1)
			return -EINVAL;
		if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
			p++;
			continue;
		}
		break;
	} while (p);

	if (!p)
		param = NULL;
	else {
		*(p - 1) = '\0';
		param = strstrip(p);
		trigger = strstrip(trigger);
	}

	attrs = parse_hist_trigger_attrs(file->tr, trigger);
	if (IS_ERR(attrs))
		return PTR_ERR(attrs);

	if (attrs->map_bits)
		hist_trigger_bits = attrs->map_bits;

	hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
	if (IS_ERR(hist_data)) {
		destroy_hist_trigger_attrs(attrs);
		return PTR_ERR(hist_data);
	}

	trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);

	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
	if (!trigger_data) {
		ret = -ENOMEM;
		goto out_free;
	}

	trigger_data->count = -1;
	trigger_data->ops = trigger_ops;
	trigger_data->cmd_ops = cmd_ops;

	INIT_LIST_HEAD(&trigger_data->list);
	RCU_INIT_POINTER(trigger_data->filter, NULL);

	trigger_data->private_data = hist_data;

	/* if param is non-empty, it's supposed to be a filter */
	if (param && cmd_ops->set_filter) {
		ret = cmd_ops->set_filter(param, trigger_data, file);
		if (ret < 0)
			goto out_free;
	}

	if (remove) {
		if (!have_hist_trigger_match(trigger_data, file))
			goto out_free;

		if (hist_trigger_check_refs(trigger_data, file)) {
			ret = -EBUSY;
			goto out_free;
		}

		cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
		se_name = trace_event_name(file->event_call);
		se = find_synth_event(se_name);
		if (se)
			se->ref--;
		ret = 0;
		goto out_free;
	}

	ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
	/*
	 * The above returns on success the # of triggers registered,
	 * but if it didn't register any it returns zero.  Consider no
	 * triggers registered a failure too.
	 */
	if (!ret) {
		if (!(attrs->pause || attrs->cont || attrs->clear))
			ret = -ENOENT;
		goto out_free;
	} else if (ret < 0)
		goto out_free;

	if (get_named_trigger_data(trigger_data))
		goto enable;

	if (has_hist_vars(hist_data))
		save_hist_vars(hist_data);

	ret = create_actions(hist_data);
	if (ret)
		goto out_unreg;

	ret = tracing_map_init(hist_data->map);
	if (ret)
		goto out_unreg;
enable:
	ret = hist_trigger_enable(trigger_data, file);
	if (ret)
		goto out_unreg;

	se_name = trace_event_name(file->event_call);
	se = find_synth_event(se_name);
	if (se)
		se->ref++;
	/* Just return zero, not the number of registered triggers */
	ret = 0;
 out:
	if (ret == 0)
		hist_err_clear();

	return ret;
 out_unreg:
	cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 out_free:
	if (cmd_ops->set_filter)
		cmd_ops->set_filter(NULL, trigger_data, NULL);

	remove_hist_vars(hist_data);

	kfree(trigger_data);

	destroy_hist_data(hist_data);
	goto out;
}

static struct event_command trigger_hist_cmd = {
	.name			= "hist",
	.trigger_type		= ETT_EVENT_HIST,
	.flags			= EVENT_CMD_FL_NEEDS_REC,
	.func			= event_hist_trigger_func,
	.reg			= hist_register_trigger,
	.unreg			= hist_unregister_trigger,
	.unreg_all		= hist_unreg_all,
	.get_trigger_ops	= event_hist_get_trigger_ops,
	.set_filter		= set_trigger_filter,
};

__init int register_trigger_hist_cmd(void)
{
	int ret;

	ret = register_event_command(&trigger_hist_cmd);
	WARN_ON(ret < 0);

	return ret;
}

static void
hist_enable_trigger(struct event_trigger_data *data, void *rec,
		    struct ring_buffer_event *event)
{
	struct enable_trigger_data *enable_data = data->private_data;
	struct event_trigger_data *test;

	list_for_each_entry_rcu(test, &enable_data->file->triggers, list,
				lockdep_is_held(&event_mutex)) {
		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
			if (enable_data->enable)
				test->paused = false;
			else
				test->paused = true;
		}
	}
}

static void
hist_enable_count_trigger(struct event_trigger_data *data, void *rec,
			  struct ring_buffer_event *event)
{
	if (!data->count)
		return;

	if (data->count != -1)
		(data->count)--;

	hist_enable_trigger(data, rec, event);
}

static struct event_trigger_ops hist_enable_trigger_ops = {
	.func			= hist_enable_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static struct event_trigger_ops hist_enable_count_trigger_ops = {
	.func			= hist_enable_count_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static struct event_trigger_ops hist_disable_trigger_ops = {
	.func			= hist_enable_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static struct event_trigger_ops hist_disable_count_trigger_ops = {
	.func			= hist_enable_count_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static struct event_trigger_ops *
hist_enable_get_trigger_ops(char *cmd, char *param)
{
	struct event_trigger_ops *ops;
	bool enable;

	enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);

	if (enable)
		ops = param ? &hist_enable_count_trigger_ops :
			&hist_enable_trigger_ops;
	else
		ops = param ? &hist_disable_count_trigger_ops :
			&hist_disable_trigger_ops;

	return ops;
}

static void hist_enable_unreg_all(struct trace_event_file *file)
{
	struct event_trigger_data *test, *n;

	list_for_each_entry_safe(test, n, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
			list_del_rcu(&test->list);
			update_cond_flag(file);
			trace_event_trigger_enable_disable(file, 0);
			if (test->ops->free)
				test->ops->free(test->ops, test);
		}
	}
}

static struct event_command trigger_hist_enable_cmd = {
	.name			= ENABLE_HIST_STR,
	.trigger_type		= ETT_HIST_ENABLE,
	.func			= event_enable_trigger_func,
	.reg			= event_enable_register_trigger,
	.unreg			= event_enable_unregister_trigger,
	.unreg_all		= hist_enable_unreg_all,
	.get_trigger_ops	= hist_enable_get_trigger_ops,
	.set_filter		= set_trigger_filter,
};

static struct event_command trigger_hist_disable_cmd = {
	.name			= DISABLE_HIST_STR,
	.trigger_type		= ETT_HIST_ENABLE,
	.func			= event_enable_trigger_func,
	.reg			= event_enable_register_trigger,
	.unreg			= event_enable_unregister_trigger,
	.unreg_all		= hist_enable_unreg_all,
	.get_trigger_ops	= hist_enable_get_trigger_ops,
	.set_filter		= set_trigger_filter,
};

static __init void unregister_trigger_hist_enable_disable_cmds(void)
{
	unregister_event_command(&trigger_hist_enable_cmd);
	unregister_event_command(&trigger_hist_disable_cmd);
}

__init int register_trigger_hist_enable_disable_cmds(void)
{
	int ret;

	ret = register_event_command(&trigger_hist_enable_cmd);
	if (WARN_ON(ret < 0))
		return ret;
	ret = register_event_command(&trigger_hist_disable_cmd);
	if (WARN_ON(ret < 0))
		unregister_trigger_hist_enable_disable_cmds();

	return ret;
}