[PW_SID:1090622] [v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE by linux-riscv-bot · Pull Request #1875 · linux-riscv/linux

linux-riscv-bot · 2026-05-06T18:21:20Z

PR for series 1090622 applied to workflow__riscv__fixes

Name: [v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1090622
Version: 2

Architectures may have bit reversal instructions, but if the API not needed, the corresponding option should not be selected because it may lead to generating the unneeded code. Signed-off-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

The generic bit reversal implementation is controlled by !HAVE_ARCH_BITREVERSE. This makes it difficult for architectures to provide a hardware-accelerated implementation while being able to fall back to the generic version if needed. This patch adds GENERIC_BITREVERSE, so bitreverse API is controlled by BITREVERSE, GENERIC_BITREVERSE and HAVE_ARCH_BITREVERSE options. The relationship between them is described as follows: - BITREVERSE is selected by user code; it's required to generate the API; - Architectures may select HAVE_ARCH_BITREVERSE and provide an arch implementation in arch/$(ARCH)/include/asm/bitrev.h. - if HAVE_ARCH_BITREVERSE isn't set, BITREVERSE selects GENERIC_BITREVERSE; - if GENERIC_BITREVERSE is set and HAVE_ARCH_BITREVERSE is not, the kernel provides generic implementation only, and wires bitrevXX() to it. - if HAVE_ARCH_BITREVERSE is set and GENERIC_BITREVERSE is not, the arch code provides __arch_bitrevXX(), and it is wired to bitrevXX(); - if both GENERIC_BITREVERSE and HAVE_ARCH_BITREVERSE are selected, the kernel generates generic___bitrev(), but wires bitrev() to the __arch_bitrev(). The last option allows architectures to use generic___bitrev() as a fallback option. Drivers and core code should never select GENERIC_BITREVERSE or HAVE_ARCH_BITREVERSE explicitly. Architectures that require generic bitreverse API as a fallback should explicitly enable GENERIC_BITREVERSE together with HAVE_ARCH_BITREVERSE. Signed-off-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

Define generic___bitrev8/16/32 using the implementation in <linux/bitrev.h>, so they can be reused in <asm/bitrev.h>, such as RISCV. Reviewed-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

The RISC-V Bit-manipulation Extension for Cryptography (Zbkb) provides the 'brev8' instruction, which reverses the bits within each byte. Combined with the 'rev8' instruction (from Zbb or Zbkb), which reverses the byte order of a register, we can efficiently implement 16-bit, 32-bit, and (on RV64) 64-bit bit reversal. This is significantly faster than the default software table-lookup implementation in lib/bitrev.c, as it replaces memory accesses and multiple arithmetic operations with just two or three hardware instructions. Select HAVE_ARCH_BITREVERSE as well as GENERIC_BITREVERSE, and provide <asm/bitrev.h> to utilize these instructions when the Zbkb extension is available at runtime via the alternatives mechanism. [Yury: select the options conditionally on BITREVERSE] Link: https://docs.riscv.org/reference/isa/unpriv/b-st-ext.html Suggested-by: David Laight <david.laight.linux@gmail.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

Arch bitrev API is covered in MAINTAINERS under the BITOPS entry, while generic bitrev is unmaintained. Move it under BITOPS too. Signed-off-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

linux-riscv-bot · 2026-05-06T18:27:39Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 143.57 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T18:45:06Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1044.85 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:08:48Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 1420.87 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:09:16Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 25.91 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:09:45Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 27.54 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:09:49Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 1.59 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:11:19Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 88.49 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:11:20Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.25 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:11:24Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
kdoc
Desc: Detects for kdoc errors
Duration: 1.30 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:11:26Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
module-param
Desc: Detect module_param changes
Duration: 0.29 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:11:28Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.24 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:11:30Z

Patch 1: "[v2,1/5] arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.32 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:14:08Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 142.00 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T19:33:30Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1160.46 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:02:10Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 1717.96 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:02:38Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 26.43 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:03:07Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 27.62 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:03:10Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 1.14 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:04:39Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 87.40 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:04:41Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.24 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:04:44Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
kdoc
Desc: Detects for kdoc errors
Duration: 0.91 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:04:46Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
module-param
Desc: Detect module_param changes
Duration: 0.27 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:04:50Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 3.12 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T20:04:52Z

Patch 2: "[v2,2/5] lib/bitrev: Introduce GENERIC_BITREVERSE"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.46 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T21:06:14Z

Patch 3: "[v2,3/5] bitops: Define generic___bitrev8/16/32 for reuse"
module-param
Desc: Detect module_param changes
Duration: 5.58 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T21:06:15Z

Patch 3: "[v2,3/5] bitops: Define generic___bitrev8/16/32 for reuse"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.30 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T21:06:17Z

Patch 3: "[v2,3/5] bitops: Define generic___bitrev8/16/32 for reuse"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.32 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T21:08:53Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 141.46 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T21:31:32Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1356.91 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:04:58Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 2004.03 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:05:26Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 26.34 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:05:54Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 27.19 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:05:58Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 2.16 seconds
Result: WARNING
Output:

WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#56: 
new file mode 100644

CHECK: Lines should not end with a '('
#77: FILE: arch/riscv/include/asm/bitrev.h:17:
+	asm volatile(

CHECK: Lines should not end with a '('
#101: FILE: arch/riscv/include/asm/bitrev.h:41:
+	asm volatile(

total: 0 errors, 1 warnings, 2 checks, 65 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit d988c6128ce0 ("arch/riscv: Add bitrev.h file to support rev8 and brev8") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT CAMELCASE COMMIT_LOG_LONG_LINE GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 1 warnings, 2 checks, 65 lines checked
CHECK: Lines should not end with a '('
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?

linux-riscv-bot · 2026-05-06T22:07:26Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 86.64 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:07:28Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.24 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:07:30Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
kdoc
Desc: Detects for kdoc errors
Duration: 0.91 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:07:32Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
module-param
Desc: Detect module_param changes
Duration: 0.26 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:07:34Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.23 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:07:36Z

Patch 4: "[v2,4/5] arch/riscv: Add bitrev.h file to support rev8 and brev8"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.31 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:10:10Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 140.57 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:27:12Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1019.99 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:50:21Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 1387.66 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:50:54Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 30.79 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:51:22Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 26.95 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:51:24Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 0.80 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:52:54Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 88.11 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:52:56Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.25 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:52:58Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
kdoc
Desc: Detects for kdoc errors
Duration: 0.95 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:53:00Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
module-param
Desc: Detect module_param changes
Duration: 0.34 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:53:02Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.24 seconds
Result: PASS

linux-riscv-bot · 2026-05-06T22:53:04Z

Patch 5: "[v2,5/5] MAINTAINERS: BITOPS: include bitrev.[ch]"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.32 seconds
Result: PASS

Linux RISC-V bot and others added 6 commits May 2, 2026 08:13

Adding CI files

2c3b264

MAINTAINERS: BITOPS: include bitrev.[ch]

e78a9ae

Arch bitrev API is covered in MAINTAINERS under the BITOPS entry, while generic bitrev is unmaintained. Move it under BITOPS too. Signed-off-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

linux-riscv-bot force-pushed the workflow__riscv__fixes branch from 2c3b264 to 2d4fcdd Compare May 10, 2026 02:08

linux-riscv-bot closed this May 14, 2026

linux-riscv-bot deleted the pw1090622 branch May 14, 2026 00:01

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