[PATCH 12/12] x86/crypto: Fix RBP usage in twofish-avx-x86_64-asm_64.S

[Josh Poimboeuf]

Using RBP as a temporary register breaks frame pointer convention and
breaks stack traces when unwinding from an interrupt in the crypto code.

Use R13 instead of RBP.  Both are callee-saved registers, so the
substitution is straightforward.

Reported-by: Eric Biggers <ebigg...@google.com>
Reported-by: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
---
 arch/x86/crypto/twofish-avx-x86_64-asm_64.S | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/crypto/twofish-avx-x86_64-asm_64.S 
b/arch/x86/crypto/twofish-avx-x86_64-asm_64.S
index b3f49d286348..73b471da3622 100644
--- a/arch/x86/crypto/twofish-avx-x86_64-asm_64.S
+++ b/arch/x86/crypto/twofish-avx-x86_64-asm_64.S
@@ -76,8 +76,8 @@
 #define RT %xmm14
 #define RR %xmm15
 
-#define RID1  %rbp
-#define RID1d %ebp
+#define RID1  %r13
+#define RID1d %r13d
 #define RID2  %rsi
 #define RID2d %esi
 
@@ -259,7 +259,7 @@ __twofish_enc_blk8:
 
        vmovdqu w(CTX), RK1;
 
-       pushq %rbp;
+       pushq %r13;
        pushq %rbx;
        pushq %rcx;
 
@@ -282,7 +282,7 @@ __twofish_enc_blk8:
 
        popq %rcx;
        popq %rbx;
-       popq %rbp;
+       popq %r13;
 
        outunpack_blocks(RC1, RD1, RA1, RB1, RK1, RX0, RY0, RK2);
        outunpack_blocks(RC2, RD2, RA2, RB2, RK1, RX0, RY0, RK2);
@@ -301,7 +301,7 @@ __twofish_dec_blk8:
 
        vmovdqu (w+4*4)(CTX), RK1;
 
-       pushq %rbp;
+       pushq %r13;
        pushq %rbx;
 
        inpack_blocks(RC1, RD1, RA1, RB1, RK1, RX0, RY0, RK2);
@@ -322,7 +322,7 @@ __twofish_dec_blk8:
        vmovdqu (w)(CTX), RK1;
 
        popq %rbx;
-       popq %rbp;
+       popq %r13;
 
        outunpack_blocks(RA1, RB1, RC1, RD1, RK1, RX0, RY0, RK2);
        outunpack_blocks(RA2, RB2, RC2, RD2, RK1, RX0, RY0, RK2);
-- 
2.13.5