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| author |   Peter Zijlstra <peterz@infradead.org> | 2022-06-14 23:15:45 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2022-06-27 10:33:58 +0200 |
| commit | aa3d480315ba6c3025a60958e1981072ea37c3df (patch) | |
| tree | 8b8c57aa9dd990a7935a210603570617180171e3 /arch/x86/include | |
| parent | x86/sev: Avoid using __x86_return_thunk (diff) | |
| download | linux-dev-aa3d480315ba6c3025a60958e1981072ea37c3df.tar.xz linux-dev-aa3d480315ba6c3025a60958e1981072ea37c3df.zip | |
x86: Use return-thunk in asm code
Use the return thunk in asm code. If the thunk isn't needed, it will
get patched into a RET instruction during boot by apply_returns().
Since alternatives can't handle relocations outside of the first
instruction, putting a 'jmp __x86_return_thunk' in one is not valid,
therefore carve out the memmove ERMS path into a separate label and jump
to it.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/linkage.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index 85865f1645bd..e3ae331cabb1 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -19,19 +19,27 @@ #define __ALIGN_STR __stringify(__ALIGN) #endif +#if defined(CONFIG_RETPOLINE) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +#define RET jmp __x86_return_thunk +#else /* CONFIG_RETPOLINE */ #ifdef CONFIG_SLS #define RET ret; int3 #else #define RET ret #endif +#endif /* CONFIG_RETPOLINE */ #else /* __ASSEMBLY__ */ +#if defined(CONFIG_RETPOLINE) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +#define ASM_RET "jmp __x86_return_thunk\n\t" +#else /* CONFIG_RETPOLINE */ #ifdef CONFIG_SLS #define ASM_RET "ret; int3\n\t" #else #define ASM_RET "ret\n\t" #endif +#endif /* CONFIG_RETPOLINE */ #endif /* __ASSEMBLY__ */ |