From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Mon, 18 Sep 2017 14:42:07 -0500
Subject: crypto: x86/sha256-avx - Fix RBP usage
Git-commit: 673ac6fbc74f835e2125df9ee39e8a2a423832e2
Patch-mainline: v4.14-rc2
References: bnc#1058115
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: Eric Biggers <ebiggers@google.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Eric Biggers <ebiggers@google.com>
Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
arch/x86/crypto/sha256-avx-asm.S | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
--- a/arch/x86/crypto/sha256-avx-asm.S
+++ b/arch/x86/crypto/sha256-avx-asm.S
@@ -103,7 +103,7 @@ SRND = %rsi # clobbers INP
c = %ecx
d = %r8d
e = %edx
-TBL = %rbp
+TBL = %r12
a = %eax
b = %ebx
@@ -350,13 +350,13 @@ a = TMP_
ENTRY(sha256_transform_avx)
.align 32
pushq %rbx
- pushq %rbp
+ pushq %r12
pushq %r13
pushq %r14
pushq %r15
- pushq %r12
+ pushq %rbp
+ movq %rsp, %rbp
- mov %rsp, %r12
subq $STACK_SIZE, %rsp # allocate stack space
and $~15, %rsp # align stack pointer
@@ -452,13 +452,12 @@ 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
ENDPROC(sha256_transform_avx)