Commit 6488bce7 authored Sep 18, 2017 by Josh Poimboeuf Committed by Herbert Xu Sep 20, 2017

crypto: x86/sha1-ssse3 - Fix RBP usage



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

Swap the usages of R12 and RBP.  Use R12 for the REG_D register, and use
RBP to store the pre-aligned stack pointer.

Reported-by: Eric Biggers <ebiggers@google.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Eric Biggers <ebiggers@google.com>
Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent d7b1722c

arch/x86/crypto/sha1_ssse3_asm.S

+5 −6

Original line number	Diff line number	Diff line
		@@ -37,7 +37,7 @@
		#define REG_A %ecx
		#define REG_B %esi
		#define REG_C %edi
		#define REG_D %ebp
		#define REG_D %r12d
		#define REG_E %edx

		#define REG_T1 %eax
		@@ -74,10 +74,10 @@
		ENTRY(\name)

		push %rbx
		push %rbp
		push %r12
		push %rbp
		mov %rsp, %rbp

		mov %rsp, %r12
		sub $64, %rsp # allocate workspace
		and $~15, %rsp # align stack

		@@ -99,10 +99,9 @@
		xor %rax, %rax
		rep stosq

		mov %r12, %rsp # deallocate workspace

		pop %r12
		mov %rbp, %rsp # deallocate workspace
		pop %rbp
		pop %r12
		pop %rbx
		ret