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authorLinus Torvalds2022-07-24 09:55:53 -0700
committerLinus Torvalds2022-07-24 09:55:53 -0700
commitaf2c9ac24019ece9281e606662e5c78fa67f5930 (patch)
treeeeb6f5dfb4a602e75b77be0dd167cfe4b08fdf53
parentc2602a7ce0fc66318325df170a9ee275d7df5c2e (diff)
parentb0380e13502adf7dd8be4c47d622c3522aae6c63 (diff)
Merge tag 'perf_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fix from Borislav Petkov: - Reorganize the perf LBR init code so that a TSX quirk is applied early enough in order for the LBR MSR access to not #GP * tag 'perf_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel/lbr: Fix unchecked MSR access error on HSW
-rw-r--r--arch/x86/events/intel/lbr.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 13179f31fe10..4f70fb6c2c1e 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -278,9 +278,9 @@ enum {
};
/*
- * For formats with LBR_TSX flags (e.g. LBR_FORMAT_EIP_FLAGS2), bits 61:62 in
- * MSR_LAST_BRANCH_FROM_x are the TSX flags when TSX is supported, but when
- * TSX is not supported they have no consistent behavior:
+ * For format LBR_FORMAT_EIP_FLAGS2, bits 61:62 in MSR_LAST_BRANCH_FROM_x
+ * are the TSX flags when TSX is supported, but when TSX is not supported
+ * they have no consistent behavior:
*
* - For wrmsr(), bits 61:62 are considered part of the sign extension.
* - For HW updates (branch captures) bits 61:62 are always OFF and are not
@@ -288,7 +288,7 @@ enum {
*
* Therefore, if:
*
- * 1) LBR has TSX format
+ * 1) LBR format LBR_FORMAT_EIP_FLAGS2
* 2) CPU has no TSX support enabled
*
* ... then any value passed to wrmsr() must be sign extended to 63 bits and any
@@ -300,7 +300,7 @@ static inline bool lbr_from_signext_quirk_needed(void)
bool tsx_support = boot_cpu_has(X86_FEATURE_HLE) ||
boot_cpu_has(X86_FEATURE_RTM);
- return !tsx_support && x86_pmu.lbr_has_tsx;
+ return !tsx_support;
}
static DEFINE_STATIC_KEY_FALSE(lbr_from_quirk_key);
@@ -1609,9 +1609,6 @@ void intel_pmu_lbr_init_hsw(void)
x86_pmu.lbr_sel_map = hsw_lbr_sel_map;
x86_get_pmu(smp_processor_id())->task_ctx_cache = create_lbr_kmem_cache(size, 0);
-
- if (lbr_from_signext_quirk_needed())
- static_branch_enable(&lbr_from_quirk_key);
}
/* skylake */
@@ -1702,7 +1699,11 @@ void intel_pmu_lbr_init(void)
switch (x86_pmu.intel_cap.lbr_format) {
case LBR_FORMAT_EIP_FLAGS2:
x86_pmu.lbr_has_tsx = 1;
- fallthrough;
+ x86_pmu.lbr_from_flags = 1;
+ if (lbr_from_signext_quirk_needed())
+ static_branch_enable(&lbr_from_quirk_key);
+ break;
+
case LBR_FORMAT_EIP_FLAGS:
x86_pmu.lbr_from_flags = 1;
break;