ARM: 6319/1: ftrace: add Thumb-2 support to dynamic ftrace

Handle the different nop and call instructions for Thumb-2. Also, we need to adjust the recorded mcount_loc addresses because they have the lsb set. Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> [recordmcount.pl change] Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: 6319/1: ftrace: add Thumb-2 support to dynamic ftrace
Handle the different nop and call instructions for Thumb-2. Also, we need to adjust the recorded mcount_loc addresses because they have the lsb set. Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> [recordmcount.pl change] Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rabin Vincent · Russell King
1 parent 3b6c223b1b
Showing 3 changed files with 36 additions and 2 deletions Side-by-side Diff
arch/arm/include/asm/ftrace.h
arch/arm/kernel/ftrace.c
scripts/recordmcount.pl
@@ -18,7 +18,8 @@
  
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
-	return addr;
+	/* With Thumb-2, the recorded addresses have the lsb set */
+	return addr & ~1;
 }
  
 extern void ftrace_caller_old(void);
@@ -18,7 +18,11 @@
 #include <asm/cacheflush.h>
 #include <asm/ftrace.h>
  
+#ifdef CONFIG_THUMB2_KERNEL
+#define	NOP		0xeb04f85d	/* pop.w {lr} */
+#else
 #define	NOP		0xe8bd4000	/* pop {lr} */
+#endif
  
 #ifdef CONFIG_OLD_MCOUNT
 #define OLD_MCOUNT_ADDR	((unsigned long) mcount)
  
  
@@ -56,10 +60,38 @@
 #endif
  
 /* construct a branch (BL) instruction to addr */
+#ifdef CONFIG_THUMB2_KERNEL
 static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
 {
+	unsigned long s, j1, j2, i1, i2, imm10, imm11;
+	unsigned long first, second;
 	long offset;
  
+	offset = (long)addr - (long)(pc + 4);
+	if (offset < -16777216 || offset > 16777214) {
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+
+	s	= (offset >> 24) & 0x1;
+	i1	= (offset >> 23) & 0x1;
+	i2	= (offset >> 22) & 0x1;
+	imm10	= (offset >> 12) & 0x3ff;
+	imm11	= (offset >>  1) & 0x7ff;
+
+	j1 = (!i1) ^ s;
+	j2 = (!i2) ^ s;
+
+	first = 0xf000 | (s << 10) | imm10;
+	second = 0xd000 | (j1 << 13) | (j2 << 11) | imm11;
+
+	return (second << 16) | first;
+}
+#else
+static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
+{
+	long offset;
+
 	offset = (long)addr - (long)(pc + 8);
 	if (unlikely(offset < -33554432 || offset > 33554428)) {
 		/* Can't generate branches that far (from ARM ARM). Ftrace
@@ -73,6 +105,7 @@
  
 	return 0xeb000000 | offset;
 }
+#endif
  
 static int ftrace_modify_code(unsigned long pc, unsigned long old,
 			      unsigned long new)
@@ -270,7 +270,7 @@
 } elsif ($arch eq "arm") {
     $alignment = 2;
     $section_type = '%progbits';
-    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24)" .
+    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24|THM_CALL)" .
 			"\\s+(__gnu_mcount_nc|mcount)\$";
  
 } elsif ($arch eq "ia64") {
...	...	@@ -18,7 +18,8 @@
18	18
19	19	static inline unsigned long ftrace_call_adjust(unsigned long addr)
20	20	{
21		- return addr;
	21	+ /* With Thumb-2, the recorded addresses have the lsb set */
	22	+ return addr & ~1;
22	23	}
23	24
24	25	extern void ftrace_caller_old(void);
...	...	@@ -18,7 +18,11 @@
18	18	#include <asm/cacheflush.h>
19	19	#include <asm/ftrace.h>
20	20
	21	+#ifdef CONFIG_THUMB2_KERNEL
	22	+#define NOP 0xeb04f85d /* pop.w {lr} */
	23	+#else
21	24	#define NOP 0xe8bd4000 /* pop {lr} */
	25	+#endif
22	26
23	27	#ifdef CONFIG_OLD_MCOUNT
24	28	#define OLD_MCOUNT_ADDR ((unsigned long) mcount)
25	29
26	30
...	...	@@ -56,10 +60,38 @@
56	60	#endif
57	61
58	62	/* construct a branch (BL) instruction to addr */
	63	+#ifdef CONFIG_THUMB2_KERNEL
59	64	static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
60	65	{
	66	+ unsigned long s, j1, j2, i1, i2, imm10, imm11;
	67	+ unsigned long first, second;
61	68	long offset;
62	69
	70	+ offset = (long)addr - (long)(pc + 4);
	71	+ if (offset < -16777216 \|\| offset > 16777214) {
	72	+ WARN_ON_ONCE(1);
	73	+ return 0;
	74	+ }
	75	+
	76	+ s = (offset >> 24) & 0x1;
	77	+ i1 = (offset >> 23) & 0x1;
	78	+ i2 = (offset >> 22) & 0x1;
	79	+ imm10 = (offset >> 12) & 0x3ff;
	80	+ imm11 = (offset >> 1) & 0x7ff;
	81	+
	82	+ j1 = (!i1) ^ s;
	83	+ j2 = (!i2) ^ s;
	84	+
	85	+ first = 0xf000 \| (s << 10) \| imm10;
	86	+ second = 0xd000 \| (j1 << 13) \| (j2 << 11) \| imm11;
	87	+
	88	+ return (second << 16) \| first;
	89	+}
	90	+#else
	91	+static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
	92	+{
	93	+ long offset;
	94	+
63	95	offset = (long)addr - (long)(pc + 8);
64	96	if (unlikely(offset < -33554432 \|\| offset > 33554428)) {
65	97	/* Can't generate branches that far (from ARM ARM). Ftrace
...	...	@@ -73,6 +105,7 @@
73	105
74	106	return 0xeb000000 \| offset;
75	107	}
	108	+#endif
76	109
77	110	static int ftrace_modify_code(unsigned long pc, unsigned long old,
78	111	unsigned long new)
...	...	@@ -270,7 +270,7 @@
270	270	} elsif ($arch eq "arm") {
271	271	$alignment = 2;
272	272	$section_type = '%progbits';
273		- $mcount_regex = "^\\s([0-9a-fA-F]+):\\sR_ARM_(CALL\|PC24)" .
	273	+ $mcount_regex = "^\\s([0-9a-fA-F]+):\\sR_ARM_(CALL\|PC24\|THM_CALL)" .
274	274	"\\s+(__gnu_mcount_nc\|mcount)\$";
275	275
276	276	} elsif ($arch eq "ia64") {