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| author |  Borislav Petkov <bp@suse.de>
| 2022-01-27 12:56:21 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de>
| 2022-04-04 10:16:52 +0200 |
| commit | 1625c833db93516faaac5feedadf8d19c14238b6 (patch) | |
| tree | cb6bfcfdbec0e67637e0cc00842c35637816051f /arch/x86/include/asm/cpufeature.h | |
| parent | Linux 5.18-rc1 (diff) | |
| download | linux-1625c833db93516faaac5feedadf8d19c14238b6.tar.gz linux-1625c833db93516faaac5feedadf8d19c14238b6.tar.bz2 linux-1625c833db93516faaac5feedadf8d19c14238b6.zip | |
x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid=
Having to give the X86_FEATURE array indices in order to disable a
feature bit for testing is not really user-friendly. So accept the
feature bit names too.
Some feature bits don't have names so there the array indices are still
accepted, of course.
Clearing CPUID flags is not something which should be done in production
so taint the kernel too.
An exemplary cmdline would then be something like:
clearcpuid=de,440,smca,succory,bmi1,3dnow
("succory" is wrong on purpose). And it says:
[ ... ] Clearing CPUID bits: de 13:24 smca (unknown: succory) bmi1 3dnow
[ Fix CONFIG_X86_FEATURE_NAMES=n build error as reported by the 0day
robot: https://lore.kernel.org/r/202203292206.ICsY2RKX-lkp@intel.com ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220127115626.14179-2-bp@alien8.de
Diffstat (limited to 'arch/x86/include/asm/cpufeature.h')
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 1261842d006c..66d3e3b1d24d 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -34,14 +34,17 @@ enum cpuid_leafs CPUID_8000_001F_EAX, }; +#define X86_CAP_FMT_NUM "%d:%d" +#define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31) + #ifdef CONFIG_X86_FEATURE_NAMES extern const char * const x86_cap_flags[NCAPINTS*32]; extern const char * const x86_power_flags[32]; #define X86_CAP_FMT "%s" #define x86_cap_flag(flag) x86_cap_flags[flag] #else -#define X86_CAP_FMT "%d:%d" -#define x86_cap_flag(flag) ((flag) >> 5), ((flag) & 31) +#define X86_CAP_FMT X86_CAP_FMT_NUM +#define x86_cap_flag x86_cap_flag_num #endif /* |