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Commit ca04c823 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Herbert Xu
Browse files

crypto: sha512-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.

Mix things up a little bit to get rid of the RBP usage, without hurting
performance too much.  Use RDI instead of RBP for the TBL pointer.  That
will clobber CTX, so spill CTX onto the stack and use R12 to read it in
the outer loop.  R12 is used as a non-persistent temporary variable
elsewhere, so it's safe to use.

Also remove the unused y4 variable.

Reported-by: default avatarEric Biggers <ebiggers3@gmail.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 539012dc

arch/x86/crypto/sha512-avx2-asm.S

+39 −36
Original line number Diff line number Diff line
@@ -69,8 +69,9 @@ XFER = YTMP0 


BYTE_FLIP_MASK  = %ymm9



# 1st arg

CTX         = %rdi

# 1st arg is %rdi, which is saved to the stack and accessed later via %r12

CTX1        = %rdi

CTX2        = %r12

# 2nd arg

INP         = %rsi

# 3rd arg
@@ -81,7 +82,7 @@ d = %r8 
e           = %rdx

y3          = %rsi



TBL   = %rbp

TBL   = %rdi # clobbers CTX1



a     = %rax

b     = %rbx
@@ -91,26 +92,26 @@ g = %r10 
h     = %r11

old_h = %r11



T1    = %r12

T1    = %r12 # clobbers CTX2

y0    = %r13

y1    = %r14

y2    = %r15



y4    = %r12



# Local variables (stack frame)

XFER_SIZE = 4*8

SRND_SIZE = 1*8

INP_SIZE = 1*8

INPEND_SIZE = 1*8

CTX_SIZE = 1*8

RSPSAVE_SIZE = 1*8

GPRSAVE_SIZE = 6*8

GPRSAVE_SIZE = 5*8



frame_XFER = 0

frame_SRND = frame_XFER + XFER_SIZE

frame_INP = frame_SRND + SRND_SIZE

frame_INPEND = frame_INP + INP_SIZE

frame_RSPSAVE = frame_INPEND + INPEND_SIZE

frame_CTX = frame_INPEND + INPEND_SIZE

frame_RSPSAVE = frame_CTX + CTX_SIZE

frame_GPRSAVE = frame_RSPSAVE + RSPSAVE_SIZE

frame_size = frame_GPRSAVE + GPRSAVE_SIZE
@@ -576,12 +577,11 @@ ENTRY(sha512_transform_rorx) 
	mov	%rax, frame_RSPSAVE(%rsp)



	# Save GPRs

	mov	%rbp, frame_GPRSAVE(%rsp)

	mov	%rbx, 8*1+frame_GPRSAVE(%rsp)

	mov	%r12, 8*2+frame_GPRSAVE(%rsp)

	mov	%r13, 8*3+frame_GPRSAVE(%rsp)

	mov	%r14, 8*4+frame_GPRSAVE(%rsp)

	mov	%r15, 8*5+frame_GPRSAVE(%rsp)

	mov	%rbx, 8*0+frame_GPRSAVE(%rsp)

	mov	%r12, 8*1+frame_GPRSAVE(%rsp)

	mov	%r13, 8*2+frame_GPRSAVE(%rsp)

	mov	%r14, 8*3+frame_GPRSAVE(%rsp)

	mov	%r15, 8*4+frame_GPRSAVE(%rsp)



	shl	$7, NUM_BLKS	# convert to bytes

	jz	done_hash
@@ -589,14 +589,17 @@ ENTRY(sha512_transform_rorx) 
	mov	NUM_BLKS, frame_INPEND(%rsp)



	## load initial digest

	mov	8*0(CTX),a

	mov	8*1(CTX),b

	mov	8*2(CTX),c

	mov	8*3(CTX),d

	mov	8*4(CTX),e

	mov	8*5(CTX),f

	mov	8*6(CTX),g

	mov	8*7(CTX),h

	mov	8*0(CTX1), a

	mov	8*1(CTX1), b

	mov	8*2(CTX1), c

	mov	8*3(CTX1), d

	mov	8*4(CTX1), e

	mov	8*5(CTX1), f

	mov	8*6(CTX1), g

	mov	8*7(CTX1), h



	# save %rdi (CTX) before it gets clobbered

	mov	%rdi, frame_CTX(%rsp)



	vmovdqa	PSHUFFLE_BYTE_FLIP_MASK(%rip), BYTE_FLIP_MASK
@@ -652,14 +655,15 @@ loop2: 
	subq	$1, frame_SRND(%rsp)

	jne	loop2



	addm	8*0(CTX),a

	addm	8*1(CTX),b

	addm	8*2(CTX),c

	addm	8*3(CTX),d

	addm	8*4(CTX),e

	addm	8*5(CTX),f

	addm	8*6(CTX),g

	addm	8*7(CTX),h

	mov	frame_CTX(%rsp), CTX2

	addm	8*0(CTX2), a

	addm	8*1(CTX2), b

	addm	8*2(CTX2), c

	addm	8*3(CTX2), d

	addm	8*4(CTX2), e

	addm	8*5(CTX2), f

	addm	8*6(CTX2), g

	addm	8*7(CTX2), h



	mov	frame_INP(%rsp), INP

	add	$128, INP
@@ -669,12 +673,11 @@ loop2: 
done_hash:



# Restore GPRs

	mov	frame_GPRSAVE(%rsp)     ,%rbp

	mov	8*1+frame_GPRSAVE(%rsp) ,%rbx

	mov	8*2+frame_GPRSAVE(%rsp) ,%r12

	mov	8*3+frame_GPRSAVE(%rsp) ,%r13

	mov	8*4+frame_GPRSAVE(%rsp) ,%r14

	mov	8*5+frame_GPRSAVE(%rsp) ,%r15

	mov	8*0+frame_GPRSAVE(%rsp), %rbx

	mov	8*1+frame_GPRSAVE(%rsp), %r12

	mov	8*2+frame_GPRSAVE(%rsp), %r13

	mov	8*3+frame_GPRSAVE(%rsp), %r14

	mov	8*4+frame_GPRSAVE(%rsp), %r15



	# Restore Stack Pointer

	mov	frame_RSPSAVE(%rsp), %rsp