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SubjectRe: [PATCH 06/12] x86/crypto: Fix RBP usage in sha1_avx2_x86_64_asm.S
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On 08/29/2017 11:05 AM, Josh Poimboeuf wrote:
> Using RBP as a temporary register breaks frame pointer convention and
> breaks stack traces when unwinding from an interrupt in the crypto code.
>
> Use R11 instead of RBP. Since R11 isn't a callee-saved register, it
> doesn't need to be saved and restored on the stack.

These changes seem okay.

Thanks.

Tim

>
> Reported-by: Eric Biggers <ebiggers@google.com>
> Reported-by: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
> ---
> arch/x86/crypto/sha1_avx2_x86_64_asm.S | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/arch/x86/crypto/sha1_avx2_x86_64_asm.S b/arch/x86/crypto/sha1_avx2_x86_64_asm.S
> index 1eab79c9ac48..9f712a7dfd79 100644
> --- a/arch/x86/crypto/sha1_avx2_x86_64_asm.S
> +++ b/arch/x86/crypto/sha1_avx2_x86_64_asm.S
> @@ -89,7 +89,7 @@
> #define REG_RE %rdx
> #define REG_RTA %r12
> #define REG_RTB %rbx
> -#define REG_T1 %ebp
> +#define REG_T1 %r11d
> #define xmm_mov vmovups
> #define avx2_zeroupper vzeroupper
> #define RND_F1 1
> @@ -637,7 +637,6 @@ _loop3:
> ENTRY(\name)
>
> push %rbx
> - push %rbp
> push %r12
> push %r13
> push %r14
> @@ -673,7 +672,6 @@ _loop3:
> pop %r14
> pop %r13
> pop %r12
> - pop %rbp
> pop %rbx
>
> ret
>

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