releases/4.10.5/crypto-powerpc-fix-initialisation-of-crc32c-context.patch

From aa2be9b3d6d2d699e9ca7cbfc00867c80e5da213 Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Fri, 3 Mar 2017 17:56:55 +1100
Subject: crypto: powerpc - Fix initialisation of crc32c context

From: Daniel Axtens <dja@axtens.net>

commit aa2be9b3d6d2d699e9ca7cbfc00867c80e5da213 upstream.

Turning on crypto self-tests on a POWER8 shows:

    alg: hash: Test 1 failed for crc32c-vpmsum
    00000000: ff ff ff ff

Comparing the code with the Intel CRC32c implementation on which
ours is based shows that we are doing an init with 0, not ~0
as CRC32c requires.

This probably wasn't caught because btrfs does its own weird
open-coded initialisation.

Initialise our internal context to ~0 on init.

This makes the self-tests pass, and btrfs continues to work.

Fixes: 6dd7a82cc54e ("crypto: powerpc - Add POWER8 optimised crc32c")
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/crypto/crc32c-vpmsum_glue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/crypto/crc32c-vpmsum_glue.c
+++ b/arch/powerpc/crypto/crc32c-vpmsum_glue.c
@@ -52,7 +52,7 @@ static int crc32c_vpmsum_cra_init(struct
 {
 	u32 *key = crypto_tfm_ctx(tfm);
 
-	*key = 0;
+	*key = ~0;
 
 	return 0;
 }