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| author |   Juergen Gross <jgross@suse.com> | 2021-03-11 15:23:11 +0100 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2021-03-11 16:57:31 +0100 |
| commit | e208b3c4a9748b2c17aa09ba663b5096ccf82dce (patch) | |
| tree | ab88643be1f56858ec128c38a394878685c4d667 | |
| parent | x86/alternative: Support not-feature (diff) | |
| download | linux-dev-e208b3c4a9748b2c17aa09ba663b5096ccf82dce.tar.xz linux-dev-e208b3c4a9748b2c17aa09ba663b5096ccf82dce.zip | |
x86/alternative: Support ALTERNATIVE_TERNARY
Add ALTERNATIVE_TERNARY support for replacing an initial instruction
with either of two instructions depending on a feature:
ALTERNATIVE_TERNARY "default_instr", FEATURE_NR,
"feature_on_instr", "feature_off_instr"
which will start with "default_instr" and at patch time will,
depending on FEATURE_NR being set or not, patch that with either
"feature_on_instr" or "feature_off_instr".
[ bp: Add comment ontop. ]
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210311142319.4723-7-jgross@suse.com
| -rw-r--r-- | arch/x86/include/asm/alternative.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 649e56f70889..17b36090d448 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -179,6 +179,11 @@ static inline int alternatives_text_reserved(void *start, void *end) ALTINSTR_REPLACEMENT(newinstr2, 2) \ ".popsection\n" +/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ +#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ + ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ + newinstr_yes, feature) + #define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \ OLDINSTR_3(oldinsn, 1, 2, 3) \ ".pushsection .altinstructions,\"a\"\n" \ @@ -210,6 +215,9 @@ static inline int alternatives_text_reserved(void *start, void *end) #define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \ asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory") +#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \ + asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory") + /* * Alternative inline assembly with input. * @@ -380,6 +388,11 @@ static inline int alternatives_text_reserved(void *start, void *end) .popsection .endm +/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ +#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ + ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ + newinstr_yes, feature + #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_ALTERNATIVE_H */ |