02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
14 Jun, 2017
1 commit
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The config option name is now renamed to 'TIMER_OF' for consistency with
the CLOCKSOURCE_OF_DECLARE => TIMER_OF_DECLARE change.Signed-off-by: Daniel Lezcano
Reviewed-by: Linus Walleij
08 May, 2017
1 commit
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This change enables the generic strncpy_from_user() and strnlen_user()
Signed-off-by: Ley Foon Tan
21 May, 2016
1 commit
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The binary GCD algorithm is based on the following facts:
1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2)
2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b)
3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b)Even on x86 machines with reasonable division hardware, the binary
algorithm runs about 25% faster (80% the execution time) than the
division-based Euclidian algorithm.On platforms like Alpha and ARMv6 where division is a function call to
emulation code, it's even more significant.There are two variants of the code here, depending on whether a fast
__ffs (find least significant set bit) instruction is available. This
allows the unpredictable branches in the bit-at-a-time shifting loop to
be eliminated.If fast __ffs is not available, the "even/odd" GCD variant is used.
I use the following code to benchmark:
#include
#include
#include
#include
#include
#include#define swap(a, b) \
do { \
a ^= b; \
b ^= a; \
a ^= b; \
} while (0)unsigned long gcd0(unsigned long a, unsigned long b)
{
unsigned long r;if (a < b) {
swap(a, b);
}if (b == 0)
return a;while ((r = a % b) != 0) {
a = b;
b = r;
}return b;
}unsigned long gcd1(unsigned long a, unsigned long b)
{
unsigned long r = a | b;if (!a || !b)
return r;b >>= __builtin_ctzl(b);
for (;;) {
a >>= __builtin_ctzl(a);
if (a == b)
return a << __builtin_ctzl(r);if (a < b)
swap(a, b);
a -= b;
}
}unsigned long gcd2(unsigned long a, unsigned long b)
{
unsigned long r = a | b;if (!a || !b)
return r;r &= -r;
while (!(b & r))
b >>= 1;for (;;) {
while (!(a & r))
a >>= 1;
if (a == b)
return a;if (a < b)
swap(a, b);
a -= b;
a >>= 1;
if (a & r)
a += b;
a >>= 1;
}
}unsigned long gcd3(unsigned long a, unsigned long b)
{
unsigned long r = a | b;if (!a || !b)
return r;b >>= __builtin_ctzl(b);
if (b == 1)
return r & -r;for (;;) {
a >>= __builtin_ctzl(a);
if (a == 1)
return r & -r;
if (a == b)
return a << __builtin_ctzl(r);if (a < b)
swap(a, b);
a -= b;
}
}unsigned long gcd4(unsigned long a, unsigned long b)
{
unsigned long r = a | b;if (!a || !b)
return r;r &= -r;
while (!(b & r))
b >>= 1;
if (b == r)
return r;for (;;) {
while (!(a & r))
a >>= 1;
if (a == r)
return r;
if (a == b)
return a;if (a < b)
swap(a, b);
a -= b;
a >>= 1;
if (a & r)
a += b;
a >>= 1;
}
}static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = {
gcd0, gcd1, gcd2, gcd3, gcd4,
};#define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0]))
#if defined(__x86_64__)
#define rdtscll(val) do { \
unsigned long __a,__d; \
__asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \
(val) = ((unsigned long long)__a) | (((unsigned long long)__d)<= start)
ret = end - start;
else
ret = ~0ULL - start + 1 + end;*res = gcd_res;
return ret;
}#else
static inline struct timespec read_time(void)
{
struct timespec time;
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time);
return time;
}static inline unsigned long long diff_time(struct timespec start, struct timespec end)
{
struct timespec temp;if ((end.tv_nsec - start.tv_nsec) < 0) {
temp.tv_sec = end.tv_sec - start.tv_sec - 1;
temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec;
} else {
temp.tv_sec = end.tv_sec - start.tv_sec;
temp.tv_nsec = end.tv_nsec - start.tv_nsec;
}return temp.tv_sec * 1000000000ULL + temp.tv_nsec;
}static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long),
unsigned long a, unsigned long b, unsigned long *res)
{
struct timespec start, end;
unsigned long gcd_res;start = read_time();
gcd_res = gcd(a, b);
end = read_time();*res = gcd_res;
return diff_time(start, end);
}#endif
static inline unsigned long get_rand()
{
if (sizeof(long) == 8)
return (unsigned long)rand() << 32 | rand();
else
return rand();
}int main(int argc, char **argv)
{
unsigned int seed = time(0);
int loops = 100;
int repeats = 1000;
unsigned long (*res)[TEST_ENTRIES];
unsigned long long elapsed[TEST_ENTRIES];
int i, j, k;for (;;) {
int opt = getopt(argc, argv, "n:r:s:");
/* End condition always first */
if (opt == -1)
break;switch (opt) {
case 'n':
loops = atoi(optarg);
break;
case 'r':
repeats = atoi(optarg);
break;
case 's':
seed = strtoul(optarg, NULL, 10);
break;
default:
/* You won't actually get here. */
break;
}
}res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops);
memset(elapsed, 0, sizeof(elapsed));srand(seed);
for (j = 0; j < loops; j++) {
unsigned long a = get_rand();
/* Do we have args? */
unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand();
unsigned long long min_elapsed[TEST_ENTRIES];
for (k = 0; k < repeats; k++) {
for (i = 0; i < TEST_ENTRIES; i++) {
unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &res[j][i]);
if (k == 0 || min_elapsed[i] > tmp)
min_elapsed[i] = tmp;
}
}
for (i = 0; i < TEST_ENTRIES; i++)
elapsed[i] += min_elapsed[i];
}for (i = 0; i < TEST_ENTRIES; i++)
printf("gcd%d: elapsed %llu\n", i, elapsed[i]);k = 0;
srand(seed);
for (j = 0; j < loops; j++) {
unsigned long a = get_rand();
unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand();
for (i = 1; i < TEST_ENTRIES; i++) {
if (res[j][i] != res[j][0])
break;
}
if (i < TEST_ENTRIES) {
if (k == 0) {
k = 1;
fprintf(stderr, "Error:\n");
}
fprintf(stderr, "gcd(%lu, %lu): ", a, b);
for (i = 0; i < TEST_ENTRIES; i++)
fprintf(stderr, "%ld%s", res[j][i], i < TEST_ENTRIES - 1 ? ", " : "\n");
}
}if (k == 0)
fprintf(stderr, "PASS\n");free(res);
return 0;
}Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got:
zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
gcd0: elapsed 10174
gcd1: elapsed 2120
gcd2: elapsed 2902
gcd3: elapsed 2039
gcd4: elapsed 2812
PASS
zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
gcd0: elapsed 9309
gcd1: elapsed 2280
gcd2: elapsed 2822
gcd3: elapsed 2217
gcd4: elapsed 2710
PASS
zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
gcd0: elapsed 9589
gcd1: elapsed 2098
gcd2: elapsed 2815
gcd3: elapsed 2030
gcd4: elapsed 2718
PASS
zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
gcd0: elapsed 9914
gcd1: elapsed 2309
gcd2: elapsed 2779
gcd3: elapsed 2228
gcd4: elapsed 2709
PASS[akpm@linux-foundation.org: avoid #defining a CONFIG_ variable]
Signed-off-by: Zhaoxiu Zeng
Signed-off-by: George Spelvin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
26 Apr, 2016
1 commit
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This symbols is not needed to get access to selecting the
GPIOLIB anymore: any arch can select GPIOLIB.Cc: Michael Büsch
Cc: nios2-dev@lists.rocketboards.org
Acked-by: Ley Foon Tan
Signed-off-by: Linus Walleij
16 Feb, 2015
1 commit
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Signed-off-by: Ley Foon Tan
10 Feb, 2015
1 commit
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Signed-off-by: Ley Foon Tan
08 Dec, 2014
3 commits
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If NIOS2_CMDLINE_IGNORE_DTB is selected but CMDLINE_BOOL isn't and thus
CONFIG_CMDLINE is not defined, the build fails with the following error:arch/nios2/kernel/setup.c: In function 'nios2_boot_init':
arch/nios2/kernel/setup.c:131:30: error: 'CONFIG_CMDLINE' undeclared
(first use in this function)
strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);This can be reproduced using randconfig with KCONFIG_SEED=0xE5B8749E, i.e.
'make KCONFIG_SEED=0xE5B8749E ARCH=nios2 randconfig'.Fix this by letting NIOS2_CMDLINE_IGNORE_DTB depend on CMDLINE_BOOL, so we
actually have a default kernel command string to fall back to.Signed-off-by: Tobias Klauser
Acked-by: Ley Foon Tan -
kernel/time/Kconfig expects that NR_CPUS is defined.
This fixes the following config warning:
"kernel/time/Kconfig:163:warning: range is invalid"Follow 4cbbbb43d666 ("microblaze: Fix missing NR_CPUS in menuconfig")
Signed-off-by: Tobias Klauser
Acked-by: Ley Foon Tan -
This patch adds Makefile and Kconfig files required for building a
nios2 kernel.Signed-off-by: Ley Foon Tan
