diff options
Diffstat (limited to 'arch/x86/events')
| -rw-r--r-- | arch/x86/events/amd/core.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c index 9b15afda0326..1fc4ce44e743 100644 --- a/arch/x86/events/amd/core.c +++ b/arch/x86/events/amd/core.c @@ -907,6 +907,37 @@ static int amd_pmu_handle_irq(struct pt_regs *regs) return amd_pmu_adjust_nmi_window(handled); } +/* + * AMD-specific callback invoked through perf_snapshot_branch_stack static + * call, defined in include/linux/perf_event.h. See its definition for API + * details. It's up to caller to provide enough space in *entries* to fit all + * LBR records, otherwise returned result will be truncated to *cnt* entries. + */ +static int amd_pmu_v2_snapshot_branch_stack(struct perf_branch_entry *entries, unsigned int cnt) +{ + struct cpu_hw_events *cpuc; + unsigned long flags; + + /* + * The sequence of steps to freeze LBR should be completely inlined + * and contain no branches to minimize contamination of LBR snapshot + */ + local_irq_save(flags); + amd_pmu_core_disable_all(); + __amd_pmu_lbr_disable(); + + cpuc = this_cpu_ptr(&cpu_hw_events); + + amd_pmu_lbr_read(); + cnt = min(cnt, x86_pmu.lbr_nr); + memcpy(entries, cpuc->lbr_entries, sizeof(struct perf_branch_entry) * cnt); + + amd_pmu_v2_enable_all(0); + local_irq_restore(flags); + + return cnt; +} + static int amd_pmu_v2_handle_irq(struct pt_regs *regs) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); @@ -1443,6 +1474,10 @@ static int __init amd_core_pmu_init(void) static_call_update(amd_pmu_branch_reset, amd_pmu_lbr_reset); static_call_update(amd_pmu_branch_add, amd_pmu_lbr_add); static_call_update(amd_pmu_branch_del, amd_pmu_lbr_del); + + /* Only support branch_stack snapshot on perfmon v2 */ + if (x86_pmu.handle_irq == amd_pmu_v2_handle_irq) + static_call_update(perf_snapshot_branch_stack, amd_pmu_v2_snapshot_branch_stack); } else if (!amd_brs_init()) { /* * BRS requires special event constraints and flushing on ctxsw. |