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#include <stdbool.h>
#include <errno.h>
#include <linux/perf_event.h>
#include "../../perf.h"
#include <linux/types.h>
#include "../../util/debug.h"
#include "../../util/tsc.h"
#include "tsc.h"
int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
struct perf_tsc_conversion *tc)
{
bool cap_user_time_zero;
u32 seq;
int i = 0;
while (1) {
seq = pc->lock;
rmb();
tc->time_mult = pc->time_mult;
tc->time_shift = pc->time_shift;
tc->time_zero = pc->time_zero;
cap_user_time_zero = pc->cap_user_time_zero;
rmb();
if (pc->lock == seq && !(seq & 1))
break;
if (++i > 10000) {
pr_debug("failed to get perf_event_mmap_page lock\n");
return -EINVAL;
}
}
if (!cap_user_time_zero)
return -EOPNOTSUPP;
return 0;
}
u64 rdtsc(void)
{
unsigned int low, high;
asm volatile("rdtsc" : "=a" (low), "=d" (high));
return low | ((u64)high) << 32;
}
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