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a578dd09 |
| 29-Jul-2025 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux
Pull CRC updates from Eric Biggers:
- Reorganize the architecture-optimized CRC code
It now lives in l
Merge tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux
Pull CRC updates from Eric Biggers:
- Reorganize the architecture-optimized CRC code
It now lives in lib/crc/$(SRCARCH)/ rather than arch/$(SRCARCH)/lib/, and it is no longer artificially split into separate generic and arch modules. This allows better inlining and dead code elimination
The generic CRC code is also no longer exported, simplifying the API. (This mirrors the similar changes to SHA-1 and SHA-2 in lib/crypto/, which can be found in the "Crypto library updates" pull request)
- Improve crc32c() performance on newer x86_64 CPUs on long messages by enabling the VPCLMULQDQ optimized code
- Simplify the crypto_shash wrappers for crc32_le() and crc32c()
Register just one shash algorithm for each that uses the (fully optimized) library functions, instead of unnecessarily providing direct access to the generic CRC code
- Remove unused and obsolete drivers for hardware CRC engines
- Remove CRC-32 combination functions that are no longer used
- Add kerneldoc for crc32_le(), crc32_be(), and crc32c()
- Convert the crc32() macro to an inline function
* tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux: (26 commits) lib/crc: x86/crc32c: Enable VPCLMULQDQ optimization where beneficial lib/crc: x86: Reorganize crc-pclmul static_call initialization lib/crc: crc64: Add include/linux/crc64.h to kernel-api.rst lib/crc: crc32: Change crc32() from macro to inline function and remove cast nvmem: layouts: Switch from crc32() to crc32_le() lib/crc: crc32: Document crc32_le(), crc32_be(), and crc32c() lib/crc: Explicitly include <linux/export.h> lib/crc: Remove ARCH_HAS_* kconfig symbols lib/crc: x86: Migrate optimized CRC code into lib/crc/ lib/crc: sparc: Migrate optimized CRC code into lib/crc/ lib/crc: s390: Migrate optimized CRC code into lib/crc/ lib/crc: riscv: Migrate optimized CRC code into lib/crc/ lib/crc: powerpc: Migrate optimized CRC code into lib/crc/ lib/crc: mips: Migrate optimized CRC code into lib/crc/ lib/crc: loongarch: Migrate optimized CRC code into lib/crc/ lib/crc: arm64: Migrate optimized CRC code into lib/crc/ lib/crc: arm: Migrate optimized CRC code into lib/crc/ lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/ lib/crc: Move files into lib/crc/ lib/crc32: Remove unused combination support ...
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1a822ea5 |
| 12-Jun-2025 |
Eric Biggers <ebiggers@kernel.org> |
lib/crc: Explicitly include <linux/export.h>
Fix build warnings with W=1 that started appearing after commit a934a57a42f6 ("scripts/misc-check: check missing #include <linux/export.h> when W=1"). W
lib/crc: Explicitly include <linux/export.h>
Fix build warnings with W=1 that started appearing after commit a934a57a42f6 ("scripts/misc-check: check missing #include <linux/export.h> when W=1"). While at it, sort the include lists alphabetically.
Link: https://lore.kernel.org/r/20250612183852.114878-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org>
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0bcfca56 |
| 07-Jun-2025 |
Eric Biggers <ebiggers@kernel.org> |
lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/
Rework how lib/crc/ supports arch-optimized code. First, instead of the arch-optimized CRC code being in arch/$(SRCARCH)/lib/, it wil
lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/
Rework how lib/crc/ supports arch-optimized code. First, instead of the arch-optimized CRC code being in arch/$(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>
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