x86/crypto/sha256-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/8048e7444c49a8137f05265262b83dc50f8fb7f3.1614182415.git.jpoimboe@redhat.com

diff --git a/arch/x86/crypto/sha256-avx2-asm.S b/arch/x86/crypto/sha256-avx2-asm.S
index 11ff60c29c8bb85c6af0b1245a95f7d311142ee0..4087f7432a7e8809a8b24e35ac14fd6323c87bb6 100644 (file)
--- 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