summaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-05 10:06:12 +0000
committerHerbert Xu <herbert@gondor.apana.org.au>2017-02-11 17:52:28 +0800
commitdb91af0fbe20474cec33263e28d15f5e6b45ebc9 (patch)
tree22ff7970897903b0418cef78a2aeb59907f5b554 /lib
parent7d6e9105026788c497f0ab32fa16c82f4ab5ff61 (diff)
crypto: algapi - make crypto_xor() and crypto_inc() alignment agnostic
Instead of unconditionally forcing 4 byte alignment for all generic chaining modes that rely on crypto_xor() or crypto_inc() (which may result in unnecessary copying of data when the underlying hardware can perform unaligned accesses efficiently), make those functions deal with unaligned input explicitly, but only if the Kconfig symbol HAVE_EFFICIENT_UNALIGNED_ACCESS is set. This will allow us to drop the alignmasks from the CBC, CMAC, CTR, CTS, PCBC and SEQIV drivers. For crypto_inc(), this simply involves making the 4-byte stride conditional on HAVE_EFFICIENT_UNALIGNED_ACCESS being set, given that it typically operates on 16 byte buffers. For crypto_xor(), an algorithm is implemented that simply runs through the input using the largest strides possible if unaligned accesses are allowed. If they are not, an optimal sequence of memory accesses is emitted that takes the relative alignment of the input buffers into account, e.g., if the relative misalignment of dst and src is 4 bytes, the entire xor operation will be completed using 4 byte loads and stores (modulo unaligned bits at the start and end). Note that all expressions involving misalign are simply eliminated by the compiler when HAVE_EFFICIENT_UNALIGNED_ACCESS is defined. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'lib')
0 files changed, 0 insertions, 0 deletions