Using RBP as a temporary register breaks frame pointer convention and
breaks stack traces when unwinding from an interrupt in the crypto code.
Use R12 instead of RBP for the TBL register. Since R12 is also used as
another temporary register (T1), it gets clobbered in each round of
computation. So the table address needs to be freshly reloaded into R12
each time it's used.
Reported-by: Eric Biggers <ebigg...@google.com>
Reported-by: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
---
arch/x86/crypto/sha256-avx2-asm.S | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/x86/crypto/sha256-avx2-asm.S
b/arch/x86/crypto/sha256-avx2-asm.S
index 89c8f09787d2..cdd647231fa9 100644
--- a/arch/x86/crypto/sha256-avx2-asm.S
+++ b/arch/x86/crypto/sha256-avx2-asm.S
@@ -99,7 +99,7 @@ e = %edx # clobbers NUM_BLKS
y3 = %esi # clobbers INP
-TBL = %rbp
+TBL = %r12 # clobbered by T1
SRND = CTX # SRND is same register as CTX
a = %eax
@@ -531,7 +531,6 @@ STACK_SIZE = _RSP + _RSP_SIZE
ENTRY(sha256_transform_rorx)
.align 32
pushq %rbx
- pushq %rbp
pushq %r12
pushq %r13
pushq %r14
@@ -568,8 +567,6 @@ 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
@@ -597,18 +594,22 @@ last_block_enter:
.align 16
loop1:
+ lea K256(%rip), TBL
vpaddd 0*32(TBL, SRND), X0, XFER
vmovdqa XFER, 0*32+_XFER(%rsp, SRND)
FOUR_ROUNDS_AND_SCHED _XFER + 0*32
+ lea K256(%rip), TBL
vpaddd 1*32(TBL, SRND), X0, XFER
vmovdqa XFER, 1*32+_XFER(%rsp, SRND)
FOUR_ROUNDS_AND_SCHED _XFER + 1*32
+ lea K256(%rip), TBL
vpaddd 2*32(TBL, SRND), X0, XFER
vmovdqa XFER, 2*32+_XFER(%rsp, SRND)
FOUR_ROUNDS_AND_SCHED _XFER + 2*32
+ lea K256(%rip), TBL
vpaddd 3*32(TBL, SRND), X0, XFER
vmovdqa XFER, 3*32+_XFER(%rsp, SRND)
FOUR_ROUNDS_AND_SCHED _XFER + 3*32
@@ -619,9 +620,12 @@ loop1:
loop2:
## Do last 16 rounds with no scheduling
+ lea K256(%rip), TBL
vpaddd 0*32(TBL, SRND), X0, XFER
vmovdqa XFER, 0*32+_XFER(%rsp, SRND)
DO_4ROUNDS _XFER + 0*32
+
+ lea K256(%rip), TBL
vpaddd 1*32(TBL, SRND), X1, XFER
vmovdqa XFER, 1*32+_XFER(%rsp, SRND)
DO_4ROUNDS _XFER + 1*32
@@ -676,9 +680,6 @@ 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 +719,6 @@ done_hash:
popq %r14
popq %r13
popq %r12
- popq %rbp
popq %rbx
ret
ENDPROC(sha256_transform_rorx)
--
2.13.5
