[tip: objtool/core] x86/crypto/sha1_avx2: Standardize stack alignment prologue

[tip-bot2 for Josh Poimboeuf]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     20114c899cafa8313534a841cab0ab1f7ab09672
Gitweb:        https://git.kernel.org/tip/20114c899cafa8313534a841cab0ab1f7ab09672
Author:        Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate:    Wed, 24 Feb 2021 10:29:21 -06:00
Committer:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CommitterDate: Mon, 19 Apr 2021 12:36:35 -05:00

x86/crypto/sha1_avx2: Standardize stack alignment prologue

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>
Tested-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Tested-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/fdaaf8670ed1f52f55ba9a6bbac98c1afddc1af6.1614182415.git.jpoimboe@xxxxxxxxxx
---
 arch/x86/crypto/sha1_avx2_x86_64_asm.S | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/crypto/sha1_avx2_x86_64_asm.S b/arch/x86/crypto/sha1_avx2_x86_64_asm.S
index 1e594d6..5eed620 100644
--- a/arch/x86/crypto/sha1_avx2_x86_64_asm.S
+++ b/arch/x86/crypto/sha1_avx2_x86_64_asm.S
@@ -645,9 +645,9 @@ _loop3:
 	RESERVE_STACK  = (W_SIZE*4 + 8+24)
 
 	/* Align stack */
-	mov	%rsp, %rbx
+	push	%rbp
+	mov	%rsp, %rbp
 	and	$~(0x20-1), %rsp
-	push	%rbx
 	sub	$RESERVE_STACK, %rsp
 
 	avx2_zeroupper
@@ -665,8 +665,8 @@ _loop3:
 
 	avx2_zeroupper
 
-	add	$RESERVE_STACK, %rsp
-	pop	%rsp
+	mov	%rbp, %rsp
+	pop	%rbp
 
 	pop	%r15
 	pop	%r14