diff options
| author | John Allen <john.allen@amd.com> | 2025-09-24 20:08:51 +0000 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-10-30 16:29:53 +0100 |
| commit | 9249bcdea0c6db4f450a9267aa6da5b4dd4153ca (patch) | |
| tree | 036bb29b88410c401eb46923fefebe94478cfe68 /arch/x86/include | |
| parent | dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa (diff) | |
x86/boot: Move boot_*msr helpers to asm/shared/msr.h
The boot_{rdmsr,wrmsr}() helpers are *just* the barebones MSR access
functionality, without any tracing or exception handling glue as it is done in
kernel proper.
Move these helpers to asm/shared/msr.h and rename to raw_{rdmsr,wrmsr}() to
indicate what they are.
[ bp: Correct the reason why those helpers exist. I should've caught that in
the original patch that added them:
176db622573f ("x86/boot: Introduce helpers for MSR reads/writes"
but oh well...
- fixup include path delimiters to <> ]
Signed-off-by: John Allen <john.allen@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://patch.msgid.link/all/20250924200852.4452-2-john.allen@amd.com
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/shared/msr.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/include/asm/shared/msr.h b/arch/x86/include/asm/shared/msr.h index 1e6ec10b3a15..a20b1c08c99f 100644 --- a/arch/x86/include/asm/shared/msr.h +++ b/arch/x86/include/asm/shared/msr.h @@ -12,4 +12,19 @@ struct msr { }; }; +/* + * The kernel proper already defines rdmsr()/wrmsr(), but they are not for the + * boot kernel since they rely on tracepoint/exception handling infrastructure + * that's not available here. + */ +static inline void raw_rdmsr(unsigned int reg, struct msr *m) +{ + asm volatile("rdmsr" : "=a" (m->l), "=d" (m->h) : "c" (reg)); +} + +static inline void raw_wrmsr(unsigned int reg, const struct msr *m) +{ + asm volatile("wrmsr" : : "c" (reg), "a"(m->l), "d" (m->h) : "memory"); +} + #endif /* _ASM_X86_SHARED_MSR_H */ |