Linus,
Please pull the latest perf/urgent Git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf-urgent-2024-03-17
# HEAD: ad8c91282c95f801c37812d59d2d9eba6899b384 perf/x86/amd/core: Avoid register reset when CPU is dead
Two x86 PMU fixes:
- Work around AMD erratum to filter out bogus LBR stack entries
- Fix incorrect PMU reset that can result in warnings (or worse)
during suspend/hibernation.
Thanks,
Ingo
------------------>
Sandipan Das (2):
perf/x86/amd/lbr: Discard erroneous branch entries
perf/x86/amd/core: Avoid register reset when CPU is dead
arch/x86/events/amd/core.c | 1 -
arch/x86/events/amd/lbr.c | 6 ++++--
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index 69a3b02e50bb..aec16e581f5b 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -604,7 +604,6 @@ static void amd_pmu_cpu_dead(int cpu)
kfree(cpuhw->lbr_sel);
cpuhw->lbr_sel = NULL;
- amd_pmu_cpu_reset(cpu);
if (!x86_pmu.amd_nb_constraints)
return;
diff --git a/arch/x86/events/amd/lbr.c b/arch/x86/events/amd/lbr.c
index eb31f850841a..4a1e600314d5 100644
--- a/arch/x86/events/amd/lbr.c
+++ b/arch/x86/events/amd/lbr.c
@@ -173,9 +173,11 @@ void amd_pmu_lbr_read(void)
/*
* Check if a branch has been logged; if valid = 0, spec = 0
- * then no branch was recorded
+ * then no branch was recorded; if reserved = 1 then an
+ * erroneous branch was recorded (see Erratum 1452)
*/
- if (!entry.to.split.valid && !entry.to.split.spec)
+ if ((!entry.to.split.valid && !entry.to.split.spec) ||
+ entry.to.split.reserved)
continue;
perf_clear_branch_entry_bitfields(br + out);