| Age | Commit message (Collapse) | Author | Lines |
|---|
|
Implement an optimized CRC64 (NVMe) algorithm for ARM64 using NEON
Polynomial Multiply Long (PMULL) instructions. The generic shift-and-XOR
software implementation is slow, which creates a bottleneck in NVMe and
other storage subsystems.
The acceleration is implemented using C intrinsics (<arm_neon.h>) rather
than raw assembly for better readability and maintainability.
Key highlights of this implementation:
- Uses 4KB chunking inside scoped_ksimd() to avoid preemption latency
spikes on large buffers.
- Pre-calculates and loads fold constants via vld1q_u64() to minimize
register spilling.
- Benchmarks show the break-even point against the generic implementation
is around 128 bytes. The PMULL path is enabled only for len >= 128.
Performance results (kunit crc_benchmark on Cortex-A72):
- Generic (len=4096): ~268 MB/s
- PMULL (len=4096): ~1556 MB/s (nearly 6x improvement)
Signed-off-by: Demian Shulhan <demyansh@gmail.com>
Link: https://lore.kernel.org/r/20260329074338.1053550-1-demyansh@gmail.com
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
CONFIG_KERNEL_MODE_NEON is always enabled on arm64, and it always has
been since its introduction in 2013. Given that and the fact that the
usefulness of kernel-mode NEON has only been increasing over time,
checking for this option in arm64-specific code is unnecessary. Remove
this check from lib/crc/ to simplify the code and prevent any future
bugs where e.g. code gets disabled due to a typo in this logic.
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260314175744.30620-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Now that crc_kunit uses the standard "depends on" pattern, enabling the
full set of CRC tests is a bit difficult, mainly due to CRC7 being
rarely used. Add a kconfig option to make it easier. It is visible
only when KUNIT, so hopefully the extra prompt won't be too annoying.
Link: https://lore.kernel.org/r/20260306033557.250499-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Like commit 4478e8eeb871 ("lib/crypto: tests: Depend on library options
rather than selecting them") did with the crypto library tests, make
crc_kunit depend on the code it tests rather than selecting it. This
follows the standard convention for KUnit and fixes an issue where
enabling KUNIT_ALL_TESTS enabled non-test code.
crc_kunit does differ from the crypto library tests in that it
consolidates the tests for multiple CRC variants, with 5 kconfig
options, into one KUnit suite. Since depending on *all* of these
kconfig options would greatly restrict the ability to enable crc_kunit,
instead just depend on *any* of these options. Update crc_kunit
accordingly to test only the reachable code.
Alternatively we could split crc_kunit into 5 test suites. But keeping
it as one is simpler for now.
Fixes: e47d9b1a76ed ("lib/crc_kunit.c: add KUnit test suite for CRC library functions")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20260306033557.250499-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
These symbols are no longer used, so remove them.
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-13-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the x86-optimized CRC code from arch/x86/lib/crc* into its new
location in lib/crc/x86/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-12-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the sparc-optimized CRC code from arch/sparc/lib/crc* into its new
location in lib/crc/sparc/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-11-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the s390-optimized CRC code from arch/s390/lib/crc* into its new
location in lib/crc/s390/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-10-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the riscv-optimized CRC code from arch/riscv/lib/crc* into its new
location in lib/crc/riscv/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-9-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the powerpc-optimized CRC code from arch/powerpc/lib/crc* into its
new location in lib/crc/powerpc/, and wire it up in the new way. This
new way of organizing the CRC code eliminates the need to artificially
split the code for each CRC variant into separate arch and generic
modules, enabling better inlining and dead code elimination. For more
details, see "lib/crc: Prepare for arch-optimized code in subdirs of
lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-8-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the mips-optimized CRC code from arch/mips/lib/crc* into its new
location in lib/crc/mips/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-7-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the loongarch-optimized CRC code from arch/loongarch/lib/crc* into
its new location in lib/crc/loongarch/, and wire it up in the new way.
This new way of organizing the CRC code eliminates the need to
artificially split the code for each CRC variant into separate arch and
generic modules, enabling better inlining and dead code elimination.
For more details, see "lib/crc: Prepare for arch-optimized code in
subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the arm64-optimized CRC code from arch/arm64/lib/crc* into its new
location in lib/crc/arm64/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move the arm-optimized CRC code from arch/arm/lib/crc* into its new
location in lib/crc/arm/, and wire it up in the new way. This new way
of organizing the CRC code eliminates the need to artificially split the
code for each CRC variant into separate arch and generic modules,
enabling better inlining and dead code elimination. For more details,
see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/".
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Rework how lib/crc/ supports arch-optimized code. First, instead of the
arch-optimized CRC code being in arch/$(SRCARCH)/lib/, it will now be in
lib/crc/$(SRCARCH)/. Second, the API functions (e.g. crc32c()),
arch-optimized functions (e.g. crc32c_arch()), and generic functions
(e.g. crc32c_base()) will now be part of a single module for each CRC
type, allowing better inlining and dead code elimination. The second
change is made possible by the first.
As an example, consider CONFIG_CRC32=m on x86. We'll now have just
crc32.ko instead of both crc32-x86.ko and crc32.ko. The two modules
were already coupled together and always both got loaded together via
direct symbol dependency, so the separation provided no benefit.
Note: later I'd like to apply the same design to lib/crypto/ too, where
often the API functions are out-of-line so this will work even better.
In those cases, for each algorithm we currently have 3 modules all
coupled together, e.g. libsha256.ko, libsha256-generic.ko, and
sha256-x86.ko. We should have just one, inline things properly, and
rely on the compiler's dead code elimination to decide the inclusion of
the generic code instead of manually setting it via kconfig.
Having arch-specific code outside arch/ was somewhat controversial when
Zinc proposed it back in 2018. But I don't think the concerns are
warranted. It's better from a technical perspective, as it enables the
improvements mentioned above. This model is already successfully used
in other places in the kernel such as lib/raid6/. The community of each
architecture still remains free to work on the code, even if it's not in
arch/. At the time there was also a desire to put the library code in
the same files as the old-school crypto API, but that was a mistake; now
that the library is separate, that's no longer a constraint either.
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-3-ebiggers@kernel.org
Link: https://lore.kernel.org/r/20250612054514.142728-1-ebiggers@kernel.org
Link: https://lore.kernel.org/r/20250621012221.4351-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
|
Move all CRC files in lib/ into a subdirectory lib/crc/ to keep them
from cluttering up the main lib/ directory.
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
|
