diff options
| author | Borislav Petkov (AMD) <bp@alien8.de> | 2025-12-30 12:07:31 +0100 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2026-01-09 11:36:52 +0100 |
| commit | 736a2dcfdae72483a36793bc92182f33bd61d30e (patch) | |
| tree | 1c5ef00b35b8e21d87a44769db89a519603fca77 /arch | |
| parent | c957072d44a735ebbe8385fc3511a4f5e6ccea93 (diff) | |
x86/CPU/AMD: Simplify the spectral chicken fix
msr_set_bit() takes a bit number to set but MSR_ZEN2_SPECTRAL_CHICKEN_BIT
is a bit mask. The usual pattern that code uses is a _BIT-named type
macro instead of a mask.
So convert it to a bit number to reflect that.
Also, msr_set_bit() already does the reading and checking whether the
bit needs to be set so use that instead of a local variable.
Fixup tabbing while at it.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://patch.msgid.link/20251230110731.28108-1-bp@kernel.org
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 10 |
2 files changed, 4 insertions, 10 deletions
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 3d0a0950d20a..43adc38d31d5 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -794,8 +794,8 @@ #define MSR_F19H_UMC_PERF_CTR 0xc0010801 /* Zen 2 */ -#define MSR_ZEN2_SPECTRAL_CHICKEN 0xc00110e3 -#define MSR_ZEN2_SPECTRAL_CHICKEN_BIT BIT_ULL(1) +#define MSR_ZEN2_SPECTRAL_CHICKEN 0xc00110e3 +#define MSR_ZEN2_SPECTRAL_CHICKEN_BIT 1 /* Fam 17h MSRs */ #define MSR_F17H_IRPERF 0xc00000e9 diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index bc94ff1e250a..ab9158c94f8c 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -900,20 +900,14 @@ static void fix_erratum_1386(struct cpuinfo_x86 *c) void init_spectral_chicken(struct cpuinfo_x86 *c) { #ifdef CONFIG_MITIGATION_UNRET_ENTRY - u64 value; - /* * On Zen2 we offer this chicken (bit) on the altar of Speculation. * * This suppresses speculation from the middle of a basic block, i.e. it * suppresses non-branch predictions. */ - if (!cpu_has(c, X86_FEATURE_HYPERVISOR)) { - if (!rdmsrq_safe(MSR_ZEN2_SPECTRAL_CHICKEN, &value)) { - value |= MSR_ZEN2_SPECTRAL_CHICKEN_BIT; - wrmsrq_safe(MSR_ZEN2_SPECTRAL_CHICKEN, value); - } - } + if (!cpu_has(c, X86_FEATURE_HYPERVISOR)) + msr_set_bit(MSR_ZEN2_SPECTRAL_CHICKEN, MSR_ZEN2_SPECTRAL_CHICKEN_BIT); #endif } |