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Commit 539012dc authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Herbert Xu
Browse files

crypto: x86/sha256-ssse3 - Fix RBP usage 



Using RBP as a temporary register breaks frame pointer convention and
breaks stack traces when unwinding from an interrupt in the crypto code.

Swap the usages of R12 and RBP.  Use R12 for the TBL register, and use
RBP to store the pre-aligned stack pointer.

Reported-by: default avatarEric Biggers <ebiggers@google.com>
Reported-by: default avatarPeter Zijlstra <peterz@infradead.org>
Tested-by: default avatarEric Biggers <ebiggers@google.com>
Acked-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent d3dfbfe2

arch/x86/crypto/sha256-ssse3-asm.S

+7 −8
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ SRND = %rsi # clobbers INP 
c = %ecx

d = %r8d

e = %edx

TBL = %rbp

TBL = %r12

a = %eax

b = %ebx
@@ -356,13 +356,13 @@ a = TMP_ 
ENTRY(sha256_transform_ssse3)

.align 32

	pushq   %rbx

	pushq   %rbp

	pushq   %r12

	pushq   %r13

	pushq   %r14

	pushq   %r15

	pushq   %r12

	pushq   %rbp

	mov	%rsp, %rbp



	mov	%rsp, %r12

	subq    $STACK_SIZE, %rsp

	and	$~15, %rsp
@@ -462,13 +462,12 @@ loop2: 


done_hash:



	mov	%r12, %rsp



	popq    %r12

	mov	%rbp, %rsp

	popq	%rbp

	popq    %r15

	popq    %r14

	popq    %r13

	popq    %rbp

	popq    %r12

	popq    %rbx



	ret