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| author |   Peter Zijlstra <peterz@infradead.org> | 2022-06-14 23:15:36 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2022-06-27 10:33:58 +0200 |
| commit | 0b53c374b9eff2255a386f1f1cfb9a928e52a5ae (patch) | |
| tree | 6c68189d053efd4ff530c6ba2b0bb86c7298d6f0 /arch/x86/include | |
| parent | x86/retpoline: Swizzle retpoline thunk (diff) | |
| download | linux-dev-0b53c374b9eff2255a386f1f1cfb9a928e52a5ae.tar.xz linux-dev-0b53c374b9eff2255a386f1f1cfb9a928e52a5ae.zip | |
x86/retpoline: Use -mfunction-return
Utilize -mfunction-return=thunk-extern when available to have the
compiler replace RET instructions with direct JMPs to the symbol
__x86_return_thunk. This does not affect assembler (.S) sources, only C
sources.
-mfunction-return=thunk-extern has been available since gcc 7.3 and
clang 15.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 5728539a3e77..829c9f827a96 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -123,6 +123,8 @@ typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE]; extern retpoline_thunk_t __x86_indirect_thunk_array[]; +extern void __x86_return_thunk(void); + #ifdef CONFIG_RETPOLINE #define GEN(reg) \ |