[PATCH v2 0/2] crypto/algapi - refactor crypto_xor() to avoid memcpy()s

[PATCH v2 0/2] crypto/algapi - refactor crypto_xor() to avoid memcpy()s

[Ard Biesheuvel]

>From 2/2:

"""
There are quite a number of occurrences in the kernel of the pattern

    if (dst != src)
            memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
    crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE);

or

    crypto_xor(keystream, src, nbytes);
    memcpy(dst, keystream, nbytes);

where crypto_xor() is preceded or followed by a memcpy() invocation
that is only there because crypto_xor() uses its output parameter as
one of the inputs.
"""

Patch #1 is a preparatory patch, which is split off for ease of review.

Patch #2 updates all occurrences of crypto_xor() involving a memcpy() to
use a new API function crypto_xor_cpy() which combines the two operations.

v2: - keep existing crypto_xor() as-is, and add crypto_xor_cpy() for the
      cases where a redundant memcpy() can be eliminated.

Ard Biesheuvel (2):
  crypto/algapi - use separate dst and src operands for __crypto_xor()
  crypto/algapi - make crypto_xor() take separate dst and src arguments

 arch/arm/crypto/aes-ce-glue.c       |  4 +---
 arch/arm/crypto/aes-neonbs-glue.c   |  5 ++--
 arch/arm64/crypto/aes-glue.c        |  4 +---
 arch/arm64/crypto/aes-neonbs-glue.c |  5 ++--
 arch/sparc/crypto/aes_glue.c        |  3 +--
 arch/x86/crypto/aesni-intel_glue.c  |  4 ++--
 arch/x86/crypto/blowfish_glue.c     |  3 +--
 arch/x86/crypto/cast5_avx_glue.c    |  3 +--
 arch/x86/crypto/des3_ede_glue.c     |  3 +--
 crypto/algapi.c                     | 25 ++++++++++++--------
 crypto/ctr.c                        |  3 +--
 crypto/pcbc.c                       | 12 ++++------
 drivers/crypto/vmx/aes_ctr.c        |  3 +--
 drivers/md/dm-crypt.c               | 11 ++++-----
 include/crypto/algapi.h             | 23 ++++++++++++++++--
 15 files changed, 59 insertions(+), 52 deletions(-)

-- 
2.9.3

[PATCH v2 1/2] crypto/algapi - use separate dst and src operands for __crypto_xor()

[Ard Biesheuvel]

In preparation of introducing crypto_xor_cpy(), which will use separate
operands for input and output, modify the __crypto_xor() implementation,
which it will share with the existing crypto_xor(), which provides the
actual functionality when not using the inline version.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 crypto/algapi.c         | 25 ++++++++++++--------
 include/crypto/algapi.h |  4 ++--
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/crypto/algapi.c b/crypto/algapi.c
index e4cc7615a139..aa699ff6c876 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -975,13 +975,15 @@ void crypto_inc(u8 *a, unsigned int size)
 }
 EXPORT_SYMBOL_GPL(crypto_inc);
 
-void __crypto_xor(u8 *dst, const u8 *src, unsigned int len)
+void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len)
 {
 	int relalign = 0;
 
 	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
 		int size = sizeof(unsigned long);
-		int d = ((unsigned long)dst ^ (unsigned long)src) & (size - 1);
+		int d = (((unsigned long)dst ^ (unsigned long)src1) |
+			 ((unsigned long)dst ^ (unsigned long)src2)) &
+			(size - 1);
 
 		relalign = d ? 1 << __ffs(d) : size;
 
@@ -992,34 +994,37 @@ void __crypto_xor(u8 *dst, const u8 *src, unsigned int len)
 		 * process the remainder of the input using optimal strides.
 		 */
 		while (((unsigned long)dst & (relalign - 1)) && len > 0) {
-			*dst++ ^= *src++;
+			*dst++ = *src1++ ^ *src2++;
 			len--;
 		}
 	}
 
 	while (IS_ENABLED(CONFIG_64BIT) && len >= 8 && !(relalign & 7)) {
-		*(u64 *)dst ^= *(u64 *)src;
+		*(u64 *)dst = *(u64 *)src1 ^  *(u64 *)src2;
 		dst += 8;
-		src += 8;
+		src1 += 8;
+		src2 += 8;
 		len -= 8;
 	}
 
 	while (len >= 4 && !(relalign & 3)) {
-		*(u32 *)dst ^= *(u32 *)src;
+		*(u32 *)dst = *(u32 *)src1 ^ *(u32 *)src2;
 		dst += 4;
-		src += 4;
+		src1 += 4;
+		src2 += 4;
 		len -= 4;
 	}
 
 	while (len >= 2 && !(relalign & 1)) {
-		*(u16 *)dst ^= *(u16 *)src;
+		*(u16 *)dst = *(u16 *)src1 ^ *(u16 *)src2;
 		dst += 2;
-		src += 2;
+		src1 += 2;
+		src2 += 2;
 		len -= 2;
 	}
 
 	while (len--)
-		*dst++ ^= *src++;
+		*dst++ = *src1++ ^ *src2++;
 }
 EXPORT_SYMBOL_GPL(__crypto_xor);
 
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index 436c4c2683c7..fd547f946bf8 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -192,7 +192,7 @@ static inline unsigned int crypto_queue_len(struct crypto_queue *queue)
 }
 
 void crypto_inc(u8 *a, unsigned int size);
-void __crypto_xor(u8 *dst, const u8 *src, unsigned int size);
+void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int size);
 
 static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
 {
@@ -207,7 +207,7 @@ static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
 			size -= sizeof(unsigned long);
 		}
 	} else {
-		__crypto_xor(dst, src, size);
+		__crypto_xor(dst, dst, src, size);
 	}
 }
 
-- 
2.9.3

[PATCH v2 2/2] crypto/algapi - make crypto_xor() take separate dst and src arguments

[Ard Biesheuvel]

There are quite a number of occurrences in the kernel of the pattern

  if (dst != src)
  	memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
  crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE);

or

  crypto_xor(keystream, src, nbytes);
  memcpy(dst, keystream, nbytes);

where crypto_xor() is preceded or followed by a memcpy() invocation
that is only there because crypto_xor() uses its output parameter as
one of the inputs. To avoid having to add new instances of this pattern
in the arm64 code, which will be refactored to implement non-SIMD
fallbacks, add an alternative implementation called crypto_xor_cpy(),
taking separate input and output arguments. This removes the need for
the separate memcpy().

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/crypto/aes-ce-glue.c       |  4 +---
 arch/arm/crypto/aes-neonbs-glue.c   |  5 ++---
 arch/arm64/crypto/aes-glue.c        |  4 +---
 arch/arm64/crypto/aes-neonbs-glue.c |  5 ++---
 arch/sparc/crypto/aes_glue.c        |  3 +--
 arch/x86/crypto/aesni-intel_glue.c  |  4 ++--
 arch/x86/crypto/blowfish_glue.c     |  3 +--
 arch/x86/crypto/cast5_avx_glue.c    |  3 +--
 arch/x86/crypto/des3_ede_glue.c     |  3 +--
 crypto/ctr.c                        |  3 +--
 crypto/pcbc.c                       | 12 ++++--------
 drivers/crypto/vmx/aes_ctr.c        |  3 +--
 drivers/md/dm-crypt.c               | 11 +++++------
 include/crypto/algapi.h             | 19 +++++++++++++++++++
 14 files changed, 42 insertions(+), 40 deletions(-)

diff --git a/arch/arm/crypto/aes-ce-glue.c b/arch/arm/crypto/aes-ce-glue.c
index 0f966a8ca1ce..d0a9cec73707 100644
--- a/arch/arm/crypto/aes-ce-glue.c
+++ b/arch/arm/crypto/aes-ce-glue.c
@@ -285,9 +285,7 @@ static int ctr_encrypt(struct skcipher_request *req)
 
 		ce_aes_ctr_encrypt(tail, NULL, (u8 *)ctx->key_enc,
 				   num_rounds(ctx), blocks, walk.iv);
-		if (tdst != tsrc)
-			memcpy(tdst, tsrc, nbytes);
-		crypto_xor(tdst, tail, nbytes);
+		crypto_xor_cpy(tdst, tsrc, tail, nbytes);
 		err = skcipher_walk_done(&walk, 0);
 	}
 	kernel_neon_end();
diff --git a/arch/arm/crypto/aes-neonbs-glue.c b/arch/arm/crypto/aes-neonbs-glue.c
index c76377961444..18768f330449 100644
--- a/arch/arm/crypto/aes-neonbs-glue.c
+++ b/arch/arm/crypto/aes-neonbs-glue.c
@@ -221,9 +221,8 @@ static int ctr_encrypt(struct skcipher_request *req)
 			u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 			u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 
-			if (dst != src)
-				memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
-			crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE);
+			crypto_xor_cpy(dst, src, final,
+				       walk.total % AES_BLOCK_SIZE);
 
 			err = skcipher_walk_done(&walk, 0);
 			break;
diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
index bcf596b0197e..0da30e3b0e4b 100644
--- a/arch/arm64/crypto/aes-glue.c
+++ b/arch/arm64/crypto/aes-glue.c
@@ -241,9 +241,7 @@ static int ctr_encrypt(struct skcipher_request *req)
 
 		aes_ctr_encrypt(tail, NULL, (u8 *)ctx->key_enc, rounds,
 				blocks, walk.iv, first);
-		if (tdst != tsrc)
-			memcpy(tdst, tsrc, nbytes);
-		crypto_xor(tdst, tail, nbytes);
+		crypto_xor_cpy(tdst, tsrc, tail, nbytes);
 		err = skcipher_walk_done(&walk, 0);
 	}
 	kernel_neon_end();
diff --git a/arch/arm64/crypto/aes-neonbs-glue.c b/arch/arm64/crypto/aes-neonbs-glue.c
index db2501d93550..9001aec16007 100644
--- a/arch/arm64/crypto/aes-neonbs-glue.c
+++ b/arch/arm64/crypto/aes-neonbs-glue.c
@@ -224,9 +224,8 @@ static int ctr_encrypt(struct skcipher_request *req)
 			u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 			u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 
-			if (dst != src)
-				memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
-			crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE);
+			crypto_xor_cpy(dst, src, final,
+				       walk.total % AES_BLOCK_SIZE);
 
 			err = skcipher_walk_done(&walk, 0);
 			break;
diff --git a/arch/sparc/crypto/aes_glue.c b/arch/sparc/crypto/aes_glue.c
index c90930de76ba..3cd4f6b198b6 100644
--- a/arch/sparc/crypto/aes_glue.c
+++ b/arch/sparc/crypto/aes_glue.c
@@ -344,8 +344,7 @@ static void ctr_crypt_final(struct crypto_sparc64_aes_ctx *ctx,
 
 	ctx->ops->ecb_encrypt(&ctx->key[0], (const u64 *)ctrblk,
 			      keystream, AES_BLOCK_SIZE);
-	crypto_xor((u8 *) keystream, src, nbytes);
-	memcpy(dst, keystream, nbytes);
+	crypto_xor_cpy(dst, (u8 *) keystream, src, nbytes);
 	crypto_inc(ctrblk, AES_BLOCK_SIZE);
 }
 
diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 4a55cdcdc008..5c15d6b57329 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -475,8 +475,8 @@ static void ctr_crypt_final(struct crypto_aes_ctx *ctx,
 	unsigned int nbytes = walk->nbytes;
 
 	aesni_enc(ctx, keystream, ctrblk);
-	crypto_xor(keystream, src, nbytes);
-	memcpy(dst, keystream, nbytes);
+	crypto_xor_cpy(dst, keystream, src, nbytes);
+
 	crypto_inc(ctrblk, AES_BLOCK_SIZE);
 }
 
diff --git a/arch/x86/crypto/blowfish_glue.c b/arch/x86/crypto/blowfish_glue.c
index 17c05531dfd1..f9eca34301e2 100644
--- a/arch/x86/crypto/blowfish_glue.c
+++ b/arch/x86/crypto/blowfish_glue.c
@@ -271,8 +271,7 @@ static void ctr_crypt_final(struct bf_ctx *ctx, struct blkcipher_walk *walk)
 	unsigned int nbytes = walk->nbytes;
 
 	blowfish_enc_blk(ctx, keystream, ctrblk);
-	crypto_xor(keystream, src, nbytes);
-	memcpy(dst, keystream, nbytes);
+	crypto_xor_cpy(dst, keystream, src, nbytes);
 
 	crypto_inc(ctrblk, BF_BLOCK_SIZE);
 }
diff --git a/arch/x86/crypto/cast5_avx_glue.c b/arch/x86/crypto/cast5_avx_glue.c
index 8648158f3916..dbea6020ffe7 100644
--- a/arch/x86/crypto/cast5_avx_glue.c
+++ b/arch/x86/crypto/cast5_avx_glue.c
@@ -256,8 +256,7 @@ static void ctr_crypt_final(struct blkcipher_desc *desc,
 	unsigned int nbytes = walk->nbytes;
 
 	__cast5_encrypt(ctx, keystream, ctrblk);
-	crypto_xor(keystream, src, nbytes);
-	memcpy(dst, keystream, nbytes);
+	crypto_xor_cpy(dst, keystream, src, nbytes);
 
 	crypto_inc(ctrblk, CAST5_BLOCK_SIZE);
 }
diff --git a/arch/x86/crypto/des3_ede_glue.c b/arch/x86/crypto/des3_ede_glue.c
index d6fc59aaaadf..30c0a37f4882 100644
--- a/arch/x86/crypto/des3_ede_glue.c
+++ b/arch/x86/crypto/des3_ede_glue.c
@@ -277,8 +277,7 @@ static void ctr_crypt_final(struct des3_ede_x86_ctx *ctx,
 	unsigned int nbytes = walk->nbytes;
 
 	des3_ede_enc_blk(ctx, keystream, ctrblk);
-	crypto_xor(keystream, src, nbytes);
-	memcpy(dst, keystream, nbytes);
+	crypto_xor_cpy(dst, keystream, src, nbytes);
 
 	crypto_inc(ctrblk, DES3_EDE_BLOCK_SIZE);
 }
diff --git a/crypto/ctr.c b/crypto/ctr.c
index 477d9226ccaa..854d924f9d8e 100644
--- a/crypto/ctr.c
+++ b/crypto/ctr.c
@@ -65,8 +65,7 @@ static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
 	unsigned int nbytes = walk->nbytes;
 
 	crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
-	crypto_xor(keystream, src, nbytes);
-	memcpy(dst, keystream, nbytes);
+	crypto_xor_cpy(dst, keystream, src, nbytes);
 
 	crypto_inc(ctrblk, bsize);
 }
diff --git a/crypto/pcbc.c b/crypto/pcbc.c
index 29dd2b4a3b85..d9e45a958720 100644
--- a/crypto/pcbc.c
+++ b/crypto/pcbc.c
@@ -55,8 +55,7 @@ static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
 	do {
 		crypto_xor(iv, src, bsize);
 		crypto_cipher_encrypt_one(tfm, dst, iv);
-		memcpy(iv, dst, bsize);
-		crypto_xor(iv, src, bsize);
+		crypto_xor_cpy(iv, dst, src, bsize);
 
 		src += bsize;
 		dst += bsize;
@@ -79,8 +78,7 @@ static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
 		memcpy(tmpbuf, src, bsize);
 		crypto_xor(iv, src, bsize);
 		crypto_cipher_encrypt_one(tfm, src, iv);
-		memcpy(iv, tmpbuf, bsize);
-		crypto_xor(iv, src, bsize);
+		crypto_xor_cpy(iv, tmpbuf, src, bsize);
 
 		src += bsize;
 	} while ((nbytes -= bsize) >= bsize);
@@ -127,8 +125,7 @@ static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
 	do {
 		crypto_cipher_decrypt_one(tfm, dst, src);
 		crypto_xor(dst, iv, bsize);
-		memcpy(iv, src, bsize);
-		crypto_xor(iv, dst, bsize);
+		crypto_xor_cpy(iv, dst, src, bsize);
 
 		src += bsize;
 		dst += bsize;
@@ -153,8 +150,7 @@ static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
 		memcpy(tmpbuf, src, bsize);
 		crypto_cipher_decrypt_one(tfm, src, src);
 		crypto_xor(src, iv, bsize);
-		memcpy(iv, tmpbuf, bsize);
-		crypto_xor(iv, src, bsize);
+		crypto_xor_cpy(iv, src, tmpbuf, bsize);
 
 		src += bsize;
 	} while ((nbytes -= bsize) >= bsize);
diff --git a/drivers/crypto/vmx/aes_ctr.c b/drivers/crypto/vmx/aes_ctr.c
index 9c26d9e8dbea..15a23f7e2e24 100644
--- a/drivers/crypto/vmx/aes_ctr.c
+++ b/drivers/crypto/vmx/aes_ctr.c
@@ -104,8 +104,7 @@ static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
 	pagefault_enable();
 	preempt_enable();
 
-	crypto_xor(keystream, src, nbytes);
-	memcpy(dst, keystream, nbytes);
+	crypto_xor(dst, keystream, src, nbytes);
 	crypto_inc(ctrblk, AES_BLOCK_SIZE);
 }
 
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index ebf9e72d479b..44f70b6271d7 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -745,9 +745,8 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc,
 	int i, r;
 
 	/* xor whitening with sector number */
-	memcpy(buf, tcw->whitening, TCW_WHITENING_SIZE);
-	crypto_xor(buf, (u8 *)&sector, 8);
-	crypto_xor(&buf[8], (u8 *)&sector, 8);
+	crypto_xor_cpy(buf, tcw->whitening, (u8 *)&sector, 8);
+	crypto_xor_cpy(&buf[8], tcw->whitening + 8, (u8 *)&sector, 8);
 
 	/* calculate crc32 for every 32bit part and xor it */
 	desc->tfm = tcw->crc32_tfm;
@@ -792,10 +791,10 @@ static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv,
 	}
 
 	/* Calculate IV */
-	memcpy(iv, tcw->iv_seed, cc->iv_size);
-	crypto_xor(iv, (u8 *)&sector, 8);
+	crypto_xor_cpy(iv, tcw->iv_seed, (u8 *)&sector, 8);
 	if (cc->iv_size > 8)
-		crypto_xor(&iv[8], (u8 *)&sector, cc->iv_size - 8);
+		crypto_xor_cpy(&iv[8], tcw->iv_seed + 8, (u8 *)&sector,
+			       cc->iv_size - 8);
 
 	return r;
 }
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index fd547f946bf8..e3cebf640c00 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -211,6 +211,25 @@ static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
 	}
 }
 
+static inline void crypto_xor_cpy(u8 *dst, const u8 *src1, const u8 *src2,
+				  unsigned int size)
+{
+	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
+	    __builtin_constant_p(size) &&
+	    (size % sizeof(unsigned long)) == 0) {
+		unsigned long *d = (unsigned long *)dst;
+		unsigned long *s1 = (unsigned long *)src1;
+		unsigned long *s2 = (unsigned long *)src2;
+
+		while (size > 0) {
+			*d++ = *s1++ ^ *s2++;
+			size -= sizeof(unsigned long);
+		}
+	} else {
+		__crypto_xor(dst, src1, src2, size);
+	}
+}
+
 int blkcipher_walk_done(struct blkcipher_desc *desc,
 			struct blkcipher_walk *walk, int err);
 int blkcipher_walk_virt(struct blkcipher_desc *desc,
-- 
2.9.3

Re: [PATCH v2 2/2] crypto/algapi - make crypto_xor() take separate dst and src arguments

[kbuild test robot]

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Hi Ard,

[auto build test ERROR on cryptodev/master]
[also build test ERROR on v4.13-rc1 next-20170721]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Ard-Biesheuvel/crypto-algapi-use-separate-dst-and-src-operands-for-__crypto_xor/20170719-090848
base:   https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=powerpc 

All errors (new ones prefixed by >>):

   drivers/crypto/vmx/aes_ctr.c: In function 'p8_aes_ctr_final':
   drivers/crypto/vmx/aes_ctr.c:107:29: warning: passing argument 3 of 'crypto_xor' makes integer from pointer without a cast [-Wint-conversion]
     crypto_xor(dst, keystream, src, nbytes);
                                ^~~
   In file included from include/crypto/scatterwalk.h:19:0,
                    from drivers/crypto/vmx/aes_ctr.c:29:
   include/crypto/algapi.h:197:20: note: expected 'unsigned int' but argument is of type 'u8 * {aka unsigned char *}'
    static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
                       ^~~~~~~~~~
>> drivers/crypto/vmx/aes_ctr.c:107:2: error: too many arguments to function 'crypto_xor'
     crypto_xor(dst, keystream, src, nbytes);
     ^~~~~~~~~~
   In file included from include/crypto/scatterwalk.h:19:0,
                    from drivers/crypto/vmx/aes_ctr.c:29:
   include/crypto/algapi.h:197:20: note: declared here
    static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
                       ^~~~~~~~~~

vim +/crypto_xor +107 drivers/crypto/vmx/aes_ctr.c

    89	
    90	static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
    91				     struct blkcipher_walk *walk)
    92	{
    93		u8 *ctrblk = walk->iv;
    94		u8 keystream[AES_BLOCK_SIZE];
    95		u8 *src = walk->src.virt.addr;
    96		u8 *dst = walk->dst.virt.addr;
    97		unsigned int nbytes = walk->nbytes;
    98	
    99		preempt_disable();
   100		pagefault_disable();
   101		enable_kernel_vsx();
   102		aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
   103		disable_kernel_vsx();
   104		pagefault_enable();
   105		preempt_enable();
   106	
 > 107		crypto_xor(dst, keystream, src, nbytes);
   108		crypto_inc(ctrblk, AES_BLOCK_SIZE);
   109	}
   110	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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