crypto: algapi - make crypto_xor() take separate dst and src arguments

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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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..17d84217dd76 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_cpy(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 cdf6b1e12460..fa17e5452796 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -758,9 +758,8 @@ 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;
@@ -805,10 +804,10 @@ 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,