diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 7 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 10 | ||||
| -rw-r--r-- | Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c | 96 | ||||
| -rw-r--r-- | Documentation/prctl/disable-tsc-on-off-stress-test.c | 95 | ||||
| -rw-r--r-- | Documentation/prctl/disable-tsc-test.c | 94 |
5 files changed, 301 insertions, 1 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index af0e9393bf6..309c47b9159 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -282,6 +282,13 @@ Why: Not used in-tree. The current out-of-tree users used it to out-of-tree driver. Who: Thomas Gleixner <tglx@linutronix.de> +---------------------------- + +What: usedac i386 kernel parameter +When: 2.6.27 +Why: replaced by allowdac and no dac combination +Who: Glauber Costa <gcosta@redhat.com> + --------------------------- What: /sys/o2cb symlink diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4b0f1ae31a4..f4839606988 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1280,8 +1280,16 @@ and is between 256 and 4096 characters. It is defined in the file noexec [IA-64] noexec [X86-32,X86-64] + On X86-32 available only on PAE configured kernels. noexec=on: enable non-executable mappings (default) - noexec=off: disable nn-executable mappings + noexec=off: disable non-executable mappings + + noexec32 [X86-64] + This affects only 32-bit executables. + noexec32=on: enable non-executable mappings (default) + read doesn't imply executable mappings + noexec32=off: disable non-executable mappings + read implies executable mappings nofxsr [BUGS=X86-32] Disables x86 floating point extended register save and restore. The kernel will only save diff --git a/Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c b/Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c new file mode 100644 index 00000000000..f8e8e95e81f --- /dev/null +++ b/Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c @@ -0,0 +1,96 @@ +/* + * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...) + * + * Tests if the control register is updated correctly + * at context switches + * + * Warning: this test will cause a very high load for a few seconds + * + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <signal.h> +#include <inttypes.h> +#include <wait.h> + + +#include <sys/prctl.h> +#include <linux/prctl.h> + +/* Get/set the process' ability to use the timestamp counter instruction */ +#ifndef PR_GET_TSC +#define PR_GET_TSC 25 +#define PR_SET_TSC 26 +# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */ +# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */ +#endif + +uint64_t rdtsc() { +uint32_t lo, hi; +/* We cannot use "=A", since this would use %rax on x86_64 */ +__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi)); +return (uint64_t)hi << 32 | lo; +} + +void sigsegv_expect(int sig) +{ + /* */ +} + +void segvtask(void) +{ + if (prctl(PR_SET_TSC, PR_TSC_SIGSEGV) < 0) + { + perror("prctl"); + exit(0); + } + signal(SIGSEGV, sigsegv_expect); + alarm(10); + rdtsc(); + fprintf(stderr, "FATAL ERROR, rdtsc() succeeded while disabled\n"); + exit(0); +} + + +void sigsegv_fail(int sig) +{ + fprintf(stderr, "FATAL ERROR, rdtsc() failed while enabled\n"); + exit(0); +} + +void rdtsctask(void) +{ + if (prctl(PR_SET_TSC, PR_TSC_ENABLE) < 0) + { + perror("prctl"); + exit(0); + } + signal(SIGSEGV, sigsegv_fail); + alarm(10); + for(;;) rdtsc(); +} + + +int main(int argc, char **argv) +{ + int n_tasks = 100, i; + + fprintf(stderr, "[No further output means we're allright]\n"); + + for (i=0; i<n_tasks; i++) + if (fork() == 0) + { + if (i & 1) + segvtask(); + else + rdtsctask(); + } + + for (i=0; i<n_tasks; i++) + wait(NULL); + + exit(0); +} + diff --git a/Documentation/prctl/disable-tsc-on-off-stress-test.c b/Documentation/prctl/disable-tsc-on-off-stress-test.c new file mode 100644 index 00000000000..1fcd9144537 --- /dev/null +++ b/Documentation/prctl/disable-tsc-on-off-stress-test.c @@ -0,0 +1,95 @@ +/* + * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...) + * + * Tests if the control register is updated correctly + * when set with prctl() + * + * Warning: this test will cause a very high load for a few seconds + * + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <signal.h> +#include <inttypes.h> +#include <wait.h> + + +#include <sys/prctl.h> +#include <linux/prctl.h> + +/* Get/set the process' ability to use the timestamp counter instruction */ +#ifndef PR_GET_TSC +#define PR_GET_TSC 25 +#define PR_SET_TSC 26 +# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */ +# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */ +#endif + +/* snippet from wikipedia :-) */ + +uint64_t rdtsc() { +uint32_t lo, hi; +/* We cannot use "=A", since this would use %rax on x86_64 */ +__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi)); +return (uint64_t)hi << 32 | lo; +} + +int should_segv = 0; + +void sigsegv_cb(int sig) +{ + if (!should_segv) + { + fprintf(stderr, "FATAL ERROR, rdtsc() failed while enabled\n"); + exit(0); + } + if (prctl(PR_SET_TSC, PR_TSC_ENABLE) < 0) + { + perror("prctl"); + exit(0); + } + should_segv = 0; + + rdtsc(); +} + +void task(void) +{ + signal(SIGSEGV, sigsegv_cb); + alarm(10); + for(;;) + { + rdtsc(); + if (should_segv) + { + fprintf(stderr, "FATAL ERROR, rdtsc() succeeded while disabled\n"); + exit(0); + } + if (prctl(PR_SET_TSC, PR_TSC_SIGSEGV) < 0) + { + perror("prctl"); + exit(0); + } + should_segv = 1; + } +} + + +int main(int argc, char **argv) +{ + int n_tasks = 100, i; + + fprintf(stderr, "[No further output means we're allright]\n"); + + for (i=0; i<n_tasks; i++) + if (fork() == 0) + task(); + + for (i=0; i<n_tasks; i++) + wait(NULL); + + exit(0); +} + diff --git a/Documentation/prctl/disable-tsc-test.c b/Documentation/prctl/disable-tsc-test.c new file mode 100644 index 00000000000..843c81eac23 --- /dev/null +++ b/Documentation/prctl/disable-tsc-test.c @@ -0,0 +1,94 @@ +/* + * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...) + * + * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <signal.h> +#include <inttypes.h> + + +#include <sys/prctl.h> +#include <linux/prctl.h> + +/* Get/set the process' ability to use the timestamp counter instruction */ +#ifndef PR_GET_TSC +#define PR_GET_TSC 25 +#define PR_SET_TSC 26 +# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */ +# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */ +#endif + +const char *tsc_names[] = +{ + [0] = "[not set]", + [PR_TSC_ENABLE] = "PR_TSC_ENABLE", + [PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV", +}; + +uint64_t rdtsc() { +uint32_t lo, hi; +/* We cannot use "=A", since this would use %rax on x86_64 */ +__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi)); +return (uint64_t)hi << 32 | lo; +} + +void sigsegv_cb(int sig) +{ + int tsc_val = 0; + + printf("[ SIG_SEGV ]\n"); + printf("prctl(PR_GET_TSC, &tsc_val); "); + fflush(stdout); + + if ( prctl(PR_GET_TSC, &tsc_val) == -1) + perror("prctl"); + + printf("tsc_val == %s\n", tsc_names[tsc_val]); + printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n"); + fflush(stdout); + if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1) + perror("prctl"); + + printf("rdtsc() == "); +} + +int main(int argc, char **argv) +{ + int tsc_val = 0; + + signal(SIGSEGV, sigsegv_cb); + + printf("rdtsc() == %llu\n", (unsigned long long)rdtsc()); + printf("prctl(PR_GET_TSC, &tsc_val); "); + fflush(stdout); + + if ( prctl(PR_GET_TSC, &tsc_val) == -1) + perror("prctl"); + + printf("tsc_val == %s\n", tsc_names[tsc_val]); + printf("rdtsc() == %llu\n", (unsigned long long)rdtsc()); + printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n"); + fflush(stdout); + + if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1) + perror("prctl"); + + printf("rdtsc() == %llu\n", (unsigned long long)rdtsc()); + printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV)\n"); + fflush(stdout); + + if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1) + perror("prctl"); + + printf("rdtsc() == "); + fflush(stdout); + printf("%llu\n", (unsigned long long)rdtsc()); + fflush(stdout); + + exit(EXIT_SUCCESS); +} + |