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Commit d3dfbfe2 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Herbert Xu
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crypto: x86/sha256-avx2 - 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.

There's no need to use RBP as a temporary register for the TBL value,
because it always stores the same value: the address of the K256 table.
Instead just reference the address of K256 directly.

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 673ac6fb

arch/x86/crypto/sha256-avx2-asm.S

+7 −15
Original line number Diff line number Diff line
@@ -98,8 +98,6 @@ d = %r8d 
e       = %edx	# clobbers NUM_BLKS

y3	= %esi	# clobbers INP





TBL	= %rbp

SRND	= CTX	# SRND is same register as CTX



a = %eax
@@ -531,7 +529,6 @@ STACK_SIZE = _RSP + _RSP_SIZE 
ENTRY(sha256_transform_rorx)

.align 32

	pushq	%rbx

	pushq	%rbp

	pushq	%r12

	pushq	%r13

	pushq	%r14
@@ -568,8 +565,6 @@ ENTRY(sha256_transform_rorx) 
	mov	CTX, _CTX(%rsp)



loop0:

	lea     K256(%rip), TBL



	## Load first 16 dwords from two blocks

	VMOVDQ	0*32(INP),XTMP0

	VMOVDQ	1*32(INP),XTMP1
@@ -597,19 +592,19 @@ last_block_enter: 


.align 16

loop1:

	vpaddd	0*32(TBL, SRND), X0, XFER

	vpaddd	K256+0*32(SRND), X0, XFER

	vmovdqa XFER, 0*32+_XFER(%rsp, SRND)

	FOUR_ROUNDS_AND_SCHED	_XFER + 0*32



	vpaddd	1*32(TBL, SRND), X0, XFER

	vpaddd	K256+1*32(SRND), X0, XFER

	vmovdqa XFER, 1*32+_XFER(%rsp, SRND)

	FOUR_ROUNDS_AND_SCHED	_XFER + 1*32



	vpaddd	2*32(TBL, SRND), X0, XFER

	vpaddd	K256+2*32(SRND), X0, XFER

	vmovdqa XFER, 2*32+_XFER(%rsp, SRND)

	FOUR_ROUNDS_AND_SCHED	_XFER + 2*32



	vpaddd	3*32(TBL, SRND), X0, XFER

	vpaddd	K256+3*32(SRND), X0, XFER

	vmovdqa XFER, 3*32+_XFER(%rsp, SRND)

	FOUR_ROUNDS_AND_SCHED	_XFER + 3*32
@@ -619,10 +614,11 @@ loop1: 


loop2:

	## Do last 16 rounds with no scheduling

	vpaddd	0*32(TBL, SRND), X0, XFER

	vpaddd	K256+0*32(SRND), X0, XFER

	vmovdqa XFER, 0*32+_XFER(%rsp, SRND)

	DO_4ROUNDS	_XFER + 0*32

	vpaddd	1*32(TBL, SRND), X1, XFER



	vpaddd	K256+1*32(SRND), X1, XFER

	vmovdqa XFER, 1*32+_XFER(%rsp, SRND)

	DO_4ROUNDS	_XFER + 1*32

	add	$2*32, SRND
@@ -676,9 +672,6 @@ loop3: 
	ja	done_hash



do_last_block:

	#### do last block

	lea	K256(%rip), TBL



	VMOVDQ	0*16(INP),XWORD0

	VMOVDQ	1*16(INP),XWORD1

	VMOVDQ	2*16(INP),XWORD2
@@ -718,7 +711,6 @@ done_hash: 
	popq	%r14

	popq	%r13

	popq	%r12

	popq	%rbp

	popq	%rbx

	ret

ENDPROC(sha256_transform_rorx)