From: Borislav Petkov <bp@suse.de>
Date: Mon, 16 May 2022 17:48:38 +0200
Subject: perf/x86/amd: Run AMD BRS code only on supported hw
Git-commit: 841b51e4a3590866d17fa2663c64688c25b891b1
Patch-mainline: v5.19-rc1
References: jsc#PED-1754 (dependent patch), jsc#PED-1755
This fires on a Fam16h machine here:
unchecked MSR access error: WRMSR to 0xc000010f (tried to write 0x0000000000000018) \
at rIP: 0xffffffff81007db1 (amd_brs_reset+0x11/0x50)
Call Trace:
<TASK>
amd_pmu_cpu_starting
? x86_pmu_dead_cpu
x86_pmu_starting_cpu
cpuhp_invoke_callback
? x86_pmu_starting_cpu
? x86_pmu_dead_cpu
cpuhp_issue_call
? x86_pmu_starting_cpu
__cpuhp_setup_state_cpuslocked
? x86_pmu_dead_cpu
? x86_pmu_starting_cpu
__cpuhp_setup_state
? map_vsyscall
init_hw_perf_events
? map_vsyscall
do_one_initcall
? _raw_spin_unlock_irqrestore
? try_to_wake_up
kernel_init_freeable
? rest_init
kernel_init
ret_from_fork
because that CPU hotplug callback gets executed on any AMD CPU - not
only on the BRS-enabled ones. Check the BRS feature bit properly.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-By: Stephane Eranian <eranian@google.com>
Link: https://lkml.kernel.org/r/20220516154838.7044-1-bp@alien8.de
Signed-off-by: Tony Jones <tonyj@suse.de>
---
arch/x86/events/amd/brs.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/amd/brs.c b/arch/x86/events/amd/brs.c
index 895c82165d85..bee8765a1e9b 100644
--- a/arch/x86/events/amd/brs.c
+++ b/arch/x86/events/amd/brs.c
@@ -57,7 +57,7 @@ static inline u64 get_debug_extn_cfg(void)
static bool __init amd_brs_detect(void)
{
- if (!boot_cpu_has(X86_FEATURE_BRS))
+ if (!cpu_feature_enabled(X86_FEATURE_BRS))
return false;
switch (boot_cpu_data.x86) {
@@ -112,6 +112,9 @@ static inline int amd_brs_get_tos(union amd_debug_extn_cfg *cfg)
*/
void amd_brs_reset(void)
{
+ if (!cpu_feature_enabled(X86_FEATURE_BRS))
+ return;
+
/*
* Reset config
*/