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authorLinus Torvalds <torvalds@linux-foundation.org>2023-09-10 20:34:46 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-09-10 20:34:46 +0300
commite79dbf03d87b2d9978d76ddc1c06424b07b215ad (patch)
treed806ba91d1843cd29a97beaf2fb5e587ecc677e1
parent535a265d7f0dd50d8c3a4f8b4f3a452d56bd160f (diff)
parent6f7f984fa85b305799076a1bcec941b9377587de (diff)
downloadlinux-e79dbf03d87b2d9978d76ddc1c06424b07b215ad.tar.xz
Merge tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 perf event fix from Ingo Molnar: "Work around a firmware bug in the uncore PMU driver, affecting certain Intel systems" * tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/uncore: Correct the number of CHAs on EMR
-rw-r--r--arch/x86/events/intel/uncore_snbep.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index 4d349986f76a..8250f0f59c2b 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -6474,8 +6474,18 @@ void spr_uncore_cpu_init(void)
type = uncore_find_type_by_id(uncore_msr_uncores, UNCORE_SPR_CHA);
if (type) {
+ /*
+ * The value from the discovery table (stored in the type->num_boxes
+ * of UNCORE_SPR_CHA) is incorrect on some SPR variants because of a
+ * firmware bug. Using the value from SPR_MSR_UNC_CBO_CONFIG to replace it.
+ */
rdmsrl(SPR_MSR_UNC_CBO_CONFIG, num_cbo);
- type->num_boxes = num_cbo;
+ /*
+ * The MSR doesn't work on the EMR XCC, but the firmware bug doesn't impact
+ * the EMR XCC. Don't let the value from the MSR replace the existing value.
+ */
+ if (num_cbo)
+ type->num_boxes = num_cbo;
}
spr_uncore_iio_free_running.num_boxes = uncore_type_max_boxes(uncore_msr_uncores, UNCORE_SPR_IIO);
}