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@redhat.com>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://lore.kernel.org/r/fdaaf8670ed1f52f55ba9a6bbac98c1afddc1af6.1614182415.git.jpoimboe@redhat.com

diff --git a/arch/x86/crypto/sha1_avx2_x86_64_asm.S b/arch/x86/crypto/sha1_avx2_x86_64_asm.S
index 1e594d60afa5605db7fecb8c336466e272a5f33d..5eed620f4676573901bd59322bee0b78bfc18356 100644 (file)
--- 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