mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-11-20 08:38:24 +08:00
f132697326
This patch adds three tests that test whether the PR_GET_TSC and PR_SET_TSC commands have the desirable effect. The tests check whether the control register is updated correctly at context switches and try to discover bugs while enabling/disabling the timestamp counter. Signed-off-by: Erik Bosman <ejbosman@cs.vu.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
97 lines
1.7 KiB
C
97 lines
1.7 KiB
C
/*
|
|
* 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);
|
|
}
|
|
|