Adrian Hunter | 3bd5a5f | 2013-06-28 16:22:19 +0300 | [diff] [blame] | 1 | #include <stdbool.h> |
| 2 | #include <errno.h> |
| 3 | |
| 4 | #include <linux/perf_event.h> |
| 5 | |
| 6 | #include "../../perf.h" |
Borislav Petkov | d944c4e | 2014-04-25 21:31:02 +0200 | [diff] [blame] | 7 | #include <linux/types.h> |
Adrian Hunter | 3bd5a5f | 2013-06-28 16:22:19 +0300 | [diff] [blame] | 8 | #include "../../util/debug.h" |
Adrian Hunter | 0b43786 | 2014-07-14 13:03:03 +0300 | [diff] [blame] | 9 | #include "../../util/tsc.h" |
Adrian Hunter | 3bd5a5f | 2013-06-28 16:22:19 +0300 | [diff] [blame] | 10 | #include "tsc.h" |
| 11 | |
Adrian Hunter | 3bd5a5f | 2013-06-28 16:22:19 +0300 | [diff] [blame] | 12 | int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc, |
| 13 | struct perf_tsc_conversion *tc) |
| 14 | { |
Peter Zijlstra | fa73158 | 2013-09-19 10:16:42 +0200 | [diff] [blame] | 15 | bool cap_user_time_zero; |
Adrian Hunter | 3bd5a5f | 2013-06-28 16:22:19 +0300 | [diff] [blame] | 16 | u32 seq; |
| 17 | int i = 0; |
| 18 | |
| 19 | while (1) { |
| 20 | seq = pc->lock; |
| 21 | rmb(); |
| 22 | tc->time_mult = pc->time_mult; |
| 23 | tc->time_shift = pc->time_shift; |
| 24 | tc->time_zero = pc->time_zero; |
Peter Zijlstra | fa73158 | 2013-09-19 10:16:42 +0200 | [diff] [blame] | 25 | cap_user_time_zero = pc->cap_user_time_zero; |
Adrian Hunter | 3bd5a5f | 2013-06-28 16:22:19 +0300 | [diff] [blame] | 26 | rmb(); |
| 27 | if (pc->lock == seq && !(seq & 1)) |
| 28 | break; |
| 29 | if (++i > 10000) { |
| 30 | pr_debug("failed to get perf_event_mmap_page lock\n"); |
| 31 | return -EINVAL; |
| 32 | } |
| 33 | } |
| 34 | |
Peter Zijlstra | fa73158 | 2013-09-19 10:16:42 +0200 | [diff] [blame] | 35 | if (!cap_user_time_zero) |
Adrian Hunter | 3bd5a5f | 2013-06-28 16:22:19 +0300 | [diff] [blame] | 36 | return -EOPNOTSUPP; |
| 37 | |
| 38 | return 0; |
| 39 | } |
Adrian Hunter | a6a69db | 2014-07-22 16:17:32 +0300 | [diff] [blame] | 40 | |
| 41 | u64 rdtsc(void) |
| 42 | { |
| 43 | unsigned int low, high; |
| 44 | |
| 45 | asm volatile("rdtsc" : "=a" (low), "=d" (high)); |
| 46 | |
| 47 | return low | ((u64)high) << 32; |
| 48 | } |