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

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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>
This commit is contained in:
Ard Biesheuvel
2017-07-24 11:28:04 +01:00
committed by Herbert Xu
parent a7c391f04f
commit 45fe93dff2
14 changed files with 42 additions and 40 deletions
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19
include/crypto/algapi.h
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@@ -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,