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Commit 2e5d2f33d1db ("crypto: arm64/aes-blk - improve XTS mask handling")
optimized away some reloads of the XTS mask vector, but failed to take
into account that calls into the XTS en/decrypt routines will take a
slightly different code path if a single block of input is split across
different buffers. So let's ensure that the first load occurs
unconditionally, and move the reload to the end so it doesn't occur
needlessly.
Fixes: 2e5d2f33d1db ("crypto: arm64/aes-blk - improve XTS mask handling")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The Crypto Extension instantiation of the aes-modes.S collection of
skciphers uses only 15 NEON registers for the round key array, whereas
the pure NEON flavor uses 16 NEON registers for the AES S-box.
This means we have a spare register available that we can use to hold
the XTS mask vector, removing the need to reload it at every iteration
of the inner loop.
Since the pure NEON version does not permit this optimization, tweak
the macros so we can factor out this functionality. Also, replace the
literal load with a short sequence to compose the mask vector.
On Cortex-A53, this results in a ~4% speedup.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Currently, we rely on the generic CTS chaining mode wrapper to
instantiate the cts(cbc(aes)) skcipher. Due to the high performance
of the ARMv8 Crypto Extensions AES instructions (~1 cycles per byte),
any overhead in the chaining mode layers is amplified, and so it pays
off considerably to fold the CTS handling into the SIMD routines.
On Cortex-A53, this results in a ~50% speedup for smaller input sizes.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The reasoning of commit f10dc56c64bb ("crypto: arm64 - revert NEON yield
for fast AEAD implementations") applies equally to skciphers: the walk
API already guarantees that the input size of each call into the NEON
code is bounded to the size of a page, and so there is no need for an
additional TIF_NEED_RESCHED flag check inside the inner loop. So revert
the skcipher changes to aes-modes.S (but retain the mac ones)
This partially reverts commit 0c8f838a52fe9fd82761861a934f16ef9896b4e5.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Replace the literal load of the addend vector with a sequence that
performs each add individually. This sequence is only 2 instructions
longer than the original, and 2% faster on Cortex-A53.
This is an improvement by itself, but also works around a Clang issue,
whose integrated assembler does not implement the GNU ARM asm syntax
completely, and does not support the =literal notation for FP registers
(more info at https://bugs.llvm.org/show_bug.cgi?id=38642)
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Avoid excessive scheduling delays under a preemptible kernel by
yielding the NEON after every block of input.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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CBC MAC is strictly sequential, and so the current AES code simply
processes the input one block at a time. However, we are about to add
yield support, which adds a bit of overhead, and which we prefer to
align with other modes in terms of granularity (i.e., it is better to
have all routines yield every 64 bytes and not have an exception for
CBC MAC which yields every 16 bytes)
So unroll the loop by 4. We still cannot perform the AES algorithm in
parallel, but we can at least merge the loads and stores.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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CBC encryption is strictly sequential, and so the current AES code
simply processes the input one block at a time. However, we are
about to add yield support, which adds a bit of overhead, and which
we prefer to align with other modes in terms of granularity (i.e.,
it is better to have all routines yield every 64 bytes and not have
an exception for CBC encrypt which yields every 16 bytes)
So unroll the loop by 4. We still cannot perform the AES algorithm in
parallel, but we can at least merge the loads and stores.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The AES block mode implementation using Crypto Extensions or plain NEON
was written before real hardware existed, and so its interleave factor
was made build time configurable (as well as an option to instantiate
all interleaved sequences inline rather than as subroutines)
We ended up using INTERLEAVE=4 with inlining disabled for both flavors
of the core AES routines, so let's stick with that, and remove the option
to configure this at build time. This makes the code easier to modify,
which is nice now that we're adding yield support.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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When kernel mode NEON was first introduced on arm64, the preserve and
restore of the userland NEON state was completely unoptimized, and
involved saving all registers on each call to kernel_neon_begin(),
and restoring them on each call to kernel_neon_end(). For this reason,
the NEON crypto code that was introduced at the time keeps the NEON
enabled throughout the execution of the crypto API methods, which may
include calls back into the crypto API that could result in memory
allocation or other actions that we should avoid when running with
preemption disabled.
Since then, we have optimized the kernel mode NEON handling, which now
restores lazily (upon return to userland), and so the preserve action
is only costly the first time it is called after entering the kernel.
So let's put the kernel_neon_begin() and kernel_neon_end() calls around
the actual invocations of the NEON crypto code, and run the remainder of
the code with kernel mode NEON disabled (and preemption enabled)
Note that this requires some reshuffling of the registers in the asm
code, because the XTS routines can no longer rely on the registers to
retain their contents between invocations.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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On ARMv8 implementations that do not support the Crypto Extensions,
such as the Raspberry Pi 3, the CCM driver falls back to the generic
table based AES implementation to perform the MAC part of the
algorithm, which is slow and not time invariant. So add a CBCMAC
implementation to the shared glue code between NEON AES and Crypto
Extensions AES, so that it can be used instead now that the CCM
driver has been updated to look for CBCMAC implementations other
than the one it supplies itself.
Also, given how these algorithms mostly only differ in the way the key
handling and the final encryption are implemented, expose CMAC and XCBC
algorithms as well based on the same core update code.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Remove the unnecessary alignmask: it is much more efficient to deal with
the misalignment in the core algorithm than relying on the crypto API to
copy the data to a suitably aligned buffer.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Update the ARMv8 Crypto Extensions and the plain NEON AES implementations
in CBC and CTR modes to return the next IV back to the skcipher API client.
This is necessary for chaining to work correctly.
Note that for CTR, this is only done if the request is a round multiple of
the block size, since otherwise, chaining is impossible anyway.
Cc: <stable@vger.kernel.org> # v3.16+
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Emit the XTS tweak literal constants in the appropriate order for a
single 128-bit scalar literal load.
Fixes: 49788fe2a128 ("arm64/crypto: AES-ECB/CBC/CTR/XTS using ARMv8 NEON and Crypto Extensions")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This adds ARMv8 implementations of AES in ECB, CBC, CTR and XTS modes,
both for ARMv8 with Crypto Extensions and for plain ARMv8 NEON.
The Crypto Extensions version can only run on ARMv8 implementations that
have support for these optional extensions.
The plain NEON version is a table based yet time invariant implementation.
All S-box substitutions are performed in parallel, leveraging the wide range
of ARMv8's tbl/tbx instructions, and the huge NEON register file, which can
comfortably hold the entire S-box and still have room to spare for doing the
actual computations.
The key expansion routines were borrowed from aes_generic.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
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