[PATCH 09/13] x86/crypto/sha256-avx2: Standardize stack alignment prologue

From: Josh Poimboeuf
Date: Wed Feb 24 2021 - 11:37:55 EST


Use a more standard prologue for saving the stack pointer before
realigning the stack.

This enables ORC unwinding by allowing objtool to understand the stack
realignment.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/crypto/sha256-avx2-asm.S | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/crypto/sha256-avx2-asm.S b/arch/x86/crypto/sha256-avx2-asm.S
index 11ff60c29c8b..4087f7432a7e 100644
--- a/arch/x86/crypto/sha256-avx2-asm.S
+++ b/arch/x86/crypto/sha256-avx2-asm.S
@@ -117,15 +117,13 @@ _XMM_SAVE_SIZE = 0
_INP_END_SIZE = 8
_INP_SIZE = 8
_CTX_SIZE = 8
-_RSP_SIZE = 8

_XFER = 0
_XMM_SAVE = _XFER + _XFER_SIZE
_INP_END = _XMM_SAVE + _XMM_SAVE_SIZE
_INP = _INP_END + _INP_END_SIZE
_CTX = _INP + _INP_SIZE
-_RSP = _CTX + _CTX_SIZE
-STACK_SIZE = _RSP + _RSP_SIZE
+STACK_SIZE = _CTX + _CTX_SIZE

# rotate_Xs
# Rotate values of symbols X0...X3
@@ -533,11 +531,11 @@ SYM_FUNC_START(sha256_transform_rorx)
pushq %r14
pushq %r15

- mov %rsp, %rax
+ push %rbp
+ mov %rsp, %rbp
+
subq $STACK_SIZE, %rsp
and $-32, %rsp # align rsp to 32 byte boundary
- mov %rax, _RSP(%rsp)
-

shl $6, NUM_BLKS # convert to bytes
jz done_hash
@@ -704,7 +702,8 @@ only_one_block:

done_hash:

- mov _RSP(%rsp), %rsp
+ mov %rbp, %rsp
+ pop %rbp

popq %r15
popq %r14
--
2.29.2