Messages in this thread Patch in this message | | | From | Alexandre Chartre <> | Subject | [PATCH V2 8/9] x86/speculation: Add unwind hint to trampoline return | Date | Tue, 7 Apr 2020 09:31:41 +0200 |
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With retpoline, the address to branch to is pushed on the stack and the return instruction (ret) is used to jump to that address. Use the UNWIND_HINT_RET_OFFSET directive to inform objtool that the stack should be adjusted.
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
replace RETPOLINE_RET with UNWIND_HINT_RET_OFFSET --- arch/x86/include/asm/nospec-branch.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index a345c6fa0541..5ce2a40a26da 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -10,6 +10,7 @@ #include <asm/alternative-asm.h> #include <asm/cpufeatures.h> #include <asm/msr-index.h> +#include <asm/unwind_hints.h> /* * This should be used immediately before a retpoline alternative. It tells @@ -100,6 +101,7 @@ jmp .Lspec_trap_\@ .Ldo_rop_\@: mov \reg, (%_ASM_SP) + UNWIND_HINT_RET_OFFSET ret .endm -- 2.18.2
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