Hi Nathan,
On Thu, 12 Jan 2023 at 08:35, Nathan Chancellor nathan@kernel.org wrote:
Hi all,
Clang can emit a few different warnings when it encounters a flag that it recognizes but does not support internally. These warnings are elevated to errors within {as,cc}-option via -Werror to catch unsupported flags that should not be added to KBUILD_{A,C}FLAGS; see commit c3f0d0bc5b01 ("kbuild, LLVMLinux: Add -Werror to cc-option to support clang").
If an unsupported flag is unconditionally to KBUILD_{A,C}FLAGS, all subsequent {as,cc}-option will always fail, preventing supported and even potentially necessary flags from getting adding to the tool flags.
One would expect these warnings to be visible in the kernel build logs since they are added to KBUILD_{A,C}FLAGS but unfortunately, these warnings are hidden with clang's -Qunused-arguments flag, which is added to KBUILD_CPPFLAGS and used for both compiling and assembling files.
Patches 1-4 address the internal inconsistencies of invoking the assembler within kbuild by using KBUILD_AFLAGS consistently and using '-x assembler-with-cpp' over '-x assembler'. This matches how assembly files are built across the kernel and helps avoid problems in situations where macro definitions or warning flags are present in KBUILD_AFLAGS, which cause instances of -Wunused-command-line-argument when the preprocessor is not called to consume them. There were a couple of places in architecture code where this change would break things so those are fixed first.
Patches 5-12 clean up warnings that will show up when -Qunused-argument is dropped. I hope none of these are controversial.
Patch 13 turns two warnings into errors so that the presence of unused flags cannot be easily ignored.
Patch 14 drops -Qunused-argument. This is done last so that it can be easily reverted if need be.
This series has seen my personal test framework, which tests several different configurations and architectures, with LLVM tip of tree (16.0.0). I have done defconfig, allmodconfig, and allnoconfig builds for arm, arm64, i386, mips, powerpc, riscv, s390, and x86_64 with GCC 12.2.0 as well but I am hoping the rest of the test infrastructure will catch any lurking problems.
I would like this series to stay together so that there is no opportunity for breakage so please consider giving acks so that this can be carried via the kbuild tree (and many thanks to the people who have already provided such tags).
Changes in v2:
- Pick up tags where provided (thank you everyone!)
- Patch 6 and 9: Clarify that '-s' is a compiler flag that is only relevant to the linking phase and remove all mention of the assembler's '-s' flag, as the assembler is never directly invoked (Nick, Segher)
- Patch 7: Move '-z noexecstack' into new ldflags-y variable (Nick)
- Patch 8: Reword commit message to explain the problem in a clearer manner (Nick)
- Link to v1: https://lore.kernel.org/r/20221228-drop-qunused-arguments-v1-0-658cbc8fc592@...
Nathan Chancellor (12): MIPS: Always use -Wa,-msoft-float and eliminate GAS_HAS_SET_HARDFLOAT MIPS: Prefer cc-option for additions to cflags powerpc: Remove linker flag from KBUILD_AFLAGS powerpc/vdso: Remove unused '-s' flag from ASFLAGS powerpc/vdso: Improve linker flags powerpc/vdso: Remove an unsupported flag from vgettimeofday-32.o with clang s390/vdso: Drop unused '-s' flag from KBUILD_AFLAGS_64 s390/vdso: Drop '-shared' from KBUILD_CFLAGS_64 s390/purgatory: Remove unused '-MD' and unnecessary '-c' flags drm/amd/display: Do not add '-mhard-float' to dml_ccflags for clang kbuild: Turn a couple more of clang's unused option warnings into errors kbuild: Stop using '-Qunused-arguments' with clang
Nick Desaulniers (2): x86/boot/compressed: prefer cc-option for CFLAGS additions kbuild: Update assembler calls to use proper flags and language target
Makefile | 1 - arch/mips/Makefile | 13 ++------- arch/mips/include/asm/asmmacro-32.h | 4 +-- arch/mips/include/asm/asmmacro.h | 42 ++++++++++++++--------------- arch/mips/include/asm/fpregdef.h | 14 ---------- arch/mips/include/asm/mipsregs.h | 20 +++----------- arch/mips/kernel/genex.S | 2 +- arch/mips/kernel/r2300_fpu.S | 4 +-- arch/mips/kernel/r4k_fpu.S | 12 ++++----- arch/mips/kvm/fpu.S | 6 ++--- arch/mips/loongson2ef/Platform | 2 +- arch/powerpc/Makefile | 2 +- arch/powerpc/kernel/vdso/Makefile | 25 +++++++++++------ arch/s390/kernel/vdso64/Makefile | 4 +-- arch/s390/purgatory/Makefile | 2 +- arch/x86/boot/compressed/Makefile | 2 +- drivers/gpu/drm/amd/display/dc/dml/Makefile | 3 ++- scripts/Kconfig.include | 2 +- scripts/Makefile.clang | 2 ++ scripts/Makefile.compiler | 8 +++--- scripts/as-version.sh | 2 +- 21 files changed, 74 insertions(+), 98 deletions(-)
FYI, [ please provide comments, feedback and improvements on build/ ltp smoke tests ]
LKFT test farm have fetched your patch series [1] [PATCH v2 00/14] Remove clang's -Qunused-arguments from KBUILD_CPPFLAGS [1] https://lore.kernel.org/llvm/20221228-drop-qunused-arguments-v2-0-9adbddd20d...
Following build warnings and errors reported.
sh: gcc-11-defconfig — FAIL gcc-11-shx3_defconfig — FAIL https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/ht...
mainline getting passed. https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test...
Build error: In function 'follow_pmd_mask', inlined from 'follow_pud_mask' at /builds/linux/mm/gup.c:735:9, inlined from 'follow_p4d_mask' at /builds/linux/mm/gup.c:752:9, inlined from 'follow_page_mask' at /builds/linux/mm/gup.c:809:9: /builds/linux/include/linux/compiler_types.h:358:45: error: call to '__compiletime_assert_263' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE(). 358 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
s390: clang-15-defconfig — FAIL https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/ht...
mainline getting passed. https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test...
Build error: make --silent --keep-going --jobs=8 O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM_IAS=0 ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- 'HOSTCC=sccache clang' 'CC=sccache clang' `.exit.text' referenced in section `__jump_table' of fs/fuse/inode.o: defined in discarded section `.exit.text' of fs/fuse/inode.o `.exit.text' referenced in section `__jump_table' of fs/fuse/inode.o: defined in discarded section `.exit.text' of fs/fuse/inode.o `.exit.text' referenced in section `__bug_table' of crypto/algboss.o: defined in discarded section `.exit.text' of crypto/algboss.o `.exit.text' referenced in section `__bug_table' of drivers/scsi/sd.o: defined in discarded section `.exit.text' of drivers/scsi/sd.o `.exit.text' referenced in section `__jump_table' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `__jump_table' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of net/iucv/iucv.o: defined in discarded section `.exit.text' of net/iucv/iucv.o `.exit.text' referenced in section `__bug_table' of drivers/s390/cio/qdio_thinint.o: defined in discarded section `.exit.text' of drivers/s390/cio/qdio_thinint.o `.exit.text' referenced in section `__bug_table' of drivers/s390/net/qeth_l3_main.o: defined in discarded section `.exit.text' of drivers/s390/net/qeth_l3_main.o `.exit.text' referenced in section `__bug_table' of drivers/s390/net/qeth_l3_main.o: defined in discarded section `.exit.text' of drivers/s390/net/qeth_l3_main.o s390x-linux-gnu-ld: BFD (GNU Binutils for Debian) 2.35.2 assertion fail ../../bfd/elf64-s390.c:3349 make[2]: *** [/builds/linux/scripts/Makefile.vmlinux:34: vmlinux] Error 1
But, Build and boot pass on arm64, arm, x86_64 and i386. Build test performed for mips, parisc, riscv, s390, sh, sparc and powerpc (known build errors for maple_defconfig and cell_defconfig),
Please refer following link for detailed build, boot, LTP smoketest. https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/ht...
Best regards Naresh Kamboju
-- Linaro LKFT https://lkft.linaro.org
base-commit: 88603b6dc419445847923fcb7fe5080067a30f98 change-id: 20221228-drop-qunused-arguments-0c5c7dae54fb
Best regards,
Nathan Chancellor nathan@kernel.org
Hi Naresh,
On Mon, Jan 23, 2023 at 07:28:10PM +0530, Naresh Kamboju wrote:
FYI, [ please provide comments, feedback and improvements on build/ ltp smoke tests ]
LKFT test farm have fetched your patch series [1] [PATCH v2 00/14] Remove clang's -Qunused-arguments from KBUILD_CPPFLAGS [1] https://lore.kernel.org/llvm/20221228-drop-qunused-arguments-v2-0-9adbddd20d...
Thank you a lot for testing this series, it is much appreciated!
It looks like this was applied on top of 6.2-rc3 if I am reading your logs right but your mainline testing is recent, 6.2-rc5. I think the errors you are seeing here are just existing mainline regressions that were later fixed.
Following build warnings and errors reported.
sh: gcc-11-defconfig — FAIL gcc-11-shx3_defconfig — FAIL https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/ht...
mainline getting passed. https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test...
Build error: In function 'follow_pmd_mask', inlined from 'follow_pud_mask' at /builds/linux/mm/gup.c:735:9, inlined from 'follow_p4d_mask' at /builds/linux/mm/gup.c:752:9, inlined from 'follow_page_mask' at /builds/linux/mm/gup.c:809:9: /builds/linux/include/linux/compiler_types.h:358:45: error: call to '__compiletime_assert_263' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE(). 358 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
I think this was fixed with mainline commit 526970be53d5 ("sh/mm: Fix pmd_t for real"), released in 6.2-rc4. You can see a previous build failing in the same manner:
https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc3-9-g5...
s390: clang-15-defconfig — FAIL https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/ht...
mainline getting passed. https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test...
Build error: make --silent --keep-going --jobs=8 O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM_IAS=0 ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- 'HOSTCC=sccache clang' 'CC=sccache clang' `.exit.text' referenced in section `__jump_table' of fs/fuse/inode.o: defined in discarded section `.exit.text' of fs/fuse/inode.o `.exit.text' referenced in section `__jump_table' of fs/fuse/inode.o: defined in discarded section `.exit.text' of fs/fuse/inode.o `.exit.text' referenced in section `__bug_table' of crypto/algboss.o: defined in discarded section `.exit.text' of crypto/algboss.o `.exit.text' referenced in section `__bug_table' of drivers/scsi/sd.o: defined in discarded section `.exit.text' of drivers/scsi/sd.o `.exit.text' referenced in section `__jump_table' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `__jump_table' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of net/iucv/iucv.o: defined in discarded section `.exit.text' of net/iucv/iucv.o `.exit.text' referenced in section `__bug_table' of drivers/s390/cio/qdio_thinint.o: defined in discarded section `.exit.text' of drivers/s390/cio/qdio_thinint.o `.exit.text' referenced in section `__bug_table' of drivers/s390/net/qeth_l3_main.o: defined in discarded section `.exit.text' of drivers/s390/net/qeth_l3_main.o `.exit.text' referenced in section `__bug_table' of drivers/s390/net/qeth_l3_main.o: defined in discarded section `.exit.text' of drivers/s390/net/qeth_l3_main.o s390x-linux-gnu-ld: BFD (GNU Binutils for Debian) 2.35.2 assertion fail ../../bfd/elf64-s390.c:3349 make[2]: *** [/builds/linux/scripts/Makefile.vmlinux:34: vmlinux] Error 1
This should be fixed with mainline commit a494398bde27 ("s390: define RUNTIME_DISCARD_EXIT to fix link error with GNU ld < 2.36"), released in 6.2-rc4 as well. Same as before, visible in mainline at one point without this series:
https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc3-9-g5...
But, Build and boot pass on arm64, arm, x86_64 and i386. Build test performed for mips, parisc, riscv, s390, sh, sparc and powerpc (known build errors for maple_defconfig and cell_defconfig),
Good to hear!
Please consider retesting this series on top of 6.2-rc5 or testing the current kbuild tree, which has this series applied in it:
https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/l...
Cheers, Nathan
Hi Nathan,
On Mon, 23 Jan 2023 at 21:41, Nathan Chancellor nathan@kernel.org wrote:
Hi Naresh,
On Mon, Jan 23, 2023 at 07:28:10PM +0530, Naresh Kamboju wrote:
FYI, [ please provide comments, feedback and improvements on build/ ltp smoke tests ]
LKFT test farm have fetched your patch series [1] [PATCH v2 00/14] Remove clang's -Qunused-arguments from KBUILD_CPPFLAGS [1] https://lore.kernel.org/llvm/20221228-drop-qunused-arguments-v2-0-9adbddd20d...
Thank you a lot for testing this series, it is much appreciated!
It looks like this was applied on top of 6.2-rc3 if I am reading your logs right but your mainline testing is recent, 6.2-rc5. I think the errors you are seeing here are just existing mainline regressions that were later fixed.
Following build warnings and errors reported.
sh: gcc-11-defconfig — FAIL gcc-11-shx3_defconfig — FAIL https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/ht...
mainline getting passed. https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test...
Build error: In function 'follow_pmd_mask', inlined from 'follow_pud_mask' at /builds/linux/mm/gup.c:735:9, inlined from 'follow_p4d_mask' at /builds/linux/mm/gup.c:752:9, inlined from 'follow_page_mask' at /builds/linux/mm/gup.c:809:9: /builds/linux/include/linux/compiler_types.h:358:45: error: call to '__compiletime_assert_263' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE(). 358 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
I think this was fixed with mainline commit 526970be53d5 ("sh/mm: Fix pmd_t for real"), released in 6.2-rc4. You can see a previous build failing in the same manner:
https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc3-9-g5...
s390: clang-15-defconfig — FAIL https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/ht...
mainline getting passed. https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc5/test...
Build error: make --silent --keep-going --jobs=8 O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM_IAS=0 ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- 'HOSTCC=sccache clang' 'CC=sccache clang' `.exit.text' referenced in section `__jump_table' of fs/fuse/inode.o: defined in discarded section `.exit.text' of fs/fuse/inode.o `.exit.text' referenced in section `__jump_table' of fs/fuse/inode.o: defined in discarded section `.exit.text' of fs/fuse/inode.o `.exit.text' referenced in section `__bug_table' of crypto/algboss.o: defined in discarded section `.exit.text' of crypto/algboss.o `.exit.text' referenced in section `__bug_table' of drivers/scsi/sd.o: defined in discarded section `.exit.text' of drivers/scsi/sd.o `.exit.text' referenced in section `__jump_table' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `__jump_table' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of drivers/md/md.o: defined in discarded section `.exit.text' of drivers/md/md.o `.exit.text' referenced in section `.altinstructions' of net/iucv/iucv.o: defined in discarded section `.exit.text' of net/iucv/iucv.o `.exit.text' referenced in section `__bug_table' of drivers/s390/cio/qdio_thinint.o: defined in discarded section `.exit.text' of drivers/s390/cio/qdio_thinint.o `.exit.text' referenced in section `__bug_table' of drivers/s390/net/qeth_l3_main.o: defined in discarded section `.exit.text' of drivers/s390/net/qeth_l3_main.o `.exit.text' referenced in section `__bug_table' of drivers/s390/net/qeth_l3_main.o: defined in discarded section `.exit.text' of drivers/s390/net/qeth_l3_main.o s390x-linux-gnu-ld: BFD (GNU Binutils for Debian) 2.35.2 assertion fail ../../bfd/elf64-s390.c:3349 make[2]: *** [/builds/linux/scripts/Makefile.vmlinux:34: vmlinux] Error 1
This should be fixed with mainline commit a494398bde27 ("s390: define RUNTIME_DISCARD_EXIT to fix link error with GNU ld < 2.36"), released in 6.2-rc4 as well. Same as before, visible in mainline at one point without this series:
https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2-rc3-9-g5...
But, Build and boot pass on arm64, arm, x86_64 and i386. Build test performed for mips, parisc, riscv, s390, sh, sparc and powerpc (known build errors for maple_defconfig and cell_defconfig),
Good to hear!
Please consider retesting this series on top of 6.2-rc5 or testing the current kbuild tree, which has this series applied in it:
This is the perfect place to test.
https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/l...
Build test pass on arm, arm64, i386, mips, parisc, powerpc, riscv, s390, sh, sparc and x86_64. Boot and LTP smoke pass on qemu-arm64, qemu-armv7, qemu-i386 and qemu-x86_64.
Tested-by: Linux Kernel Functional Testing lkft@linaro.org Tested-by: Anders Roxell anders.roxell@linaro.org
Please refer to the following link for details of testing. https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/li...
metadata: git_describe : v6.2-rc5-46-ga778c9dd138b git_repo : https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git git_sha : a778c9dd138b4f4410779705b444d58ce6f8fc44 git_short_log : a778c9dd138b ("builddeb: clean generated package content")
-- Linaro LKFT https://lkft.linaro.org
Cheers, Nathan
-
Naresh Kamboju -
Nathan Chancellor