diff options
| author | Kim Phillips | 2021-08-17 17:10:42 -0500 |
|---|---|---|
| committer | Ingo Molnar | 2021-08-26 08:58:02 +0200 |
| commit | 26db2e0c51fe83e1dd852c1321407835b481806e (patch) | |
| tree | 30b289fd7faadcd661cbad57e2c0740023e77ad5 /arch | |
| parent | 0b3a8738b76fe2087f7bc2bd59f4c78504c79180 (diff) | |
perf/x86/amd/ibs: Work around erratum #1197
Erratum #1197 "IBS (Instruction Based Sampling) Register State May be
Incorrect After Restore From CC6" is published in a document:
"Revision Guide for AMD Family 19h Models 00h-0Fh Processors" 56683 Rev. 1.04 July 2021
https://bugzilla.kernel.org/show_bug.cgi?id=206537
Implement the erratum's suggested workaround and ignore IBS samples if
MSRC001_1031 == 0.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210817221048.88063-3-kim.phillips@amd.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/events/amd/ibs.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c index 40669eac9d6d..921f47b9bb24 100644 --- a/arch/x86/events/amd/ibs.c +++ b/arch/x86/events/amd/ibs.c @@ -90,6 +90,7 @@ struct perf_ibs { unsigned long offset_mask[1]; int offset_max; unsigned int fetch_count_reset_broken : 1; + unsigned int fetch_ignore_if_zero_rip : 1; struct cpu_perf_ibs __percpu *pcpu; struct attribute **format_attrs; @@ -672,6 +673,10 @@ fail: if (check_rip && (ibs_data.regs[2] & IBS_RIP_INVALID)) { regs.flags &= ~PERF_EFLAGS_EXACT; } else { + /* Workaround for erratum #1197 */ + if (perf_ibs->fetch_ignore_if_zero_rip && !(ibs_data.regs[1])) + goto out; + set_linear_ip(®s, ibs_data.regs[1]); regs.flags |= PERF_EFLAGS_EXACT; } @@ -769,6 +774,9 @@ static __init void perf_event_ibs_init(void) if (boot_cpu_data.x86 >= 0x16 && boot_cpu_data.x86 <= 0x18) perf_ibs_fetch.fetch_count_reset_broken = 1; + if (boot_cpu_data.x86 == 0x19 && boot_cpu_data.x86_model < 0x10) + perf_ibs_fetch.fetch_ignore_if_zero_rip = 1; + perf_ibs_pmu_init(&perf_ibs_fetch, "ibs_fetch"); if (ibs_caps & IBS_CAPS_OPCNT) { |