diff options
| author | Borislav Petkov (AMD) <bp@alien8.de> | 2022-12-22 12:42:24 +0100 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-01-05 12:46:47 +0100 |
| commit | 5d1dd961e74334a2178264193ea813d44ce5e725 (patch) | |
| tree | eef12ffd72004f8f6e3a10b6bfb73fdbcb8cec01 /tools/objtool | |
| parent | 1b929c02afd37871d5afb9d498426f83432e71c2 (diff) | |
x86/alternatives: Add alt_instr.flags
Add a struct alt_instr.flags field which will contain different flags
controlling alternatives patching behavior.
The initial idea was to be able to specify it as a separate macro
parameter but that would mean touching all possible invocations of the
alternatives macros and thus a lot of churn.
What is more, as PeterZ suggested, being able to say ALT_NOT(feature) is
very readable and explains exactly what is meant.
So make the feature field a u32 where the patching flags are the upper
u16 part of the dword quantity while the lower u16 word is the feature.
The highest feature number currently is 0x26a (i.e., word 19) so there
is plenty of space. If that becomes insufficient, the field can be
extended to u64 which will then make struct alt_instr of the nice size
of 16 bytes (14 bytes currently).
There should be no functional changes resulting from this.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/Y6RCoJEtxxZWwotd@zn.tnic
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/arch/x86/include/arch/special.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/tools/objtool/arch/x86/include/arch/special.h b/tools/objtool/arch/x86/include/arch/special.h index f2918f789a0a..ca8131352994 100644 --- a/tools/objtool/arch/x86/include/arch/special.h +++ b/tools/objtool/arch/x86/include/arch/special.h @@ -11,11 +11,11 @@ #define JUMP_NEW_OFFSET 4 #define JUMP_KEY_OFFSET 8 -#define ALT_ENTRY_SIZE 12 +#define ALT_ENTRY_SIZE 14 #define ALT_ORIG_OFFSET 0 #define ALT_NEW_OFFSET 4 #define ALT_FEATURE_OFFSET 8 -#define ALT_ORIG_LEN_OFFSET 10 -#define ALT_NEW_LEN_OFFSET 11 +#define ALT_ORIG_LEN_OFFSET 12 +#define ALT_NEW_LEN_OFFSET 13 #endif /* _X86_ARCH_SPECIAL_H */ |