Hi Tiezhu and Arnd, On Thu, Jun 22, 2023 at 10:13:38PM +0800, Tiezhu Yang wrote: > Now we specify the minimal version of GCC as 5.1 and Clang/LLVM as 11.0.0 > in Documentation/process/changes.rst, __CHAR_BIT__ and __SIZEOF_LONG__ are > usable, it is probably fine to unify the definition of __BITS_PER_LONG as > (__CHAR_BIT__ * __SIZEOF_LONG__) in asm-generic uapi bitsperlong.h. > > In order to keep safe and avoid regression, only unify uapi bitsperlong.h > for some archs such as arm64, riscv and loongarch which are using newer > toolchains that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__. > > Suggested-by: Xi Ruoyao <xry111@xxxxxxxxxxx> > Link: https://lore.kernel.org/all/d3e255e4746de44c9903c4433616d44ffcf18d1b.camel@xxxxxxxxxxx/ > Suggested-by: Arnd Bergmann <arnd@xxxxxxxx> > Link: https://lore.kernel.org/linux-arch/a3a4f48a-07d4-4ed9-bc53-5d383428bdd2@xxxxxxxxxxxxxxxx/ > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> > --- > arch/arm64/include/uapi/asm/bitsperlong.h | 24 ---------------------- > arch/loongarch/include/uapi/asm/bitsperlong.h | 9 -------- > arch/riscv/include/uapi/asm/bitsperlong.h | 14 ------------- > include/uapi/asm-generic/bitsperlong.h | 13 +++++++++++- > tools/arch/arm64/include/uapi/asm/bitsperlong.h | 24 ---------------------- > .../arch/loongarch/include/uapi/asm/bitsperlong.h | 9 -------- > tools/arch/riscv/include/uapi/asm/bitsperlong.h | 14 ------------- > tools/include/uapi/asm-generic/bitsperlong.h | 14 ++++++++++++- > tools/include/uapi/asm/bitsperlong.h | 6 ------ > 9 files changed, 25 insertions(+), 102 deletions(-) > delete mode 100644 arch/arm64/include/uapi/asm/bitsperlong.h > delete mode 100644 arch/loongarch/include/uapi/asm/bitsperlong.h > delete mode 100644 arch/riscv/include/uapi/asm/bitsperlong.h > delete mode 100644 tools/arch/arm64/include/uapi/asm/bitsperlong.h > delete mode 100644 tools/arch/loongarch/include/uapi/asm/bitsperlong.h > delete mode 100644 tools/arch/riscv/include/uapi/asm/bitsperlong.h I think this change has backwards compatibility concerns, as it breaks building certain host tools on the stable releases (at least 6.4 and 6.1, as that is where I noticed this). I see the following error on my aarch64 system: $ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux- mrproper defconfig prepare In file included from /usr/include/asm/bitsperlong.h:1, from /usr/include/asm-generic/int-ll64.h:12, from /usr/include/asm-generic/types.h:7, from /usr/include/asm/types.h:1, from tools/include/linux/types.h:13, from tools/arch/x86/include/asm/orc_types.h:9, from scripts/sorttable.h:96, from scripts/sorttable.c:201: tools/include/asm-generic/bitsperlong.h:14:2: error: #error Inconsistent word size. Check asm/bitsperlong.h 14 | #error Inconsistent word size. Check asm/bitsperlong.h | ^~~~~ A reverse bisect of 6.4 to 6.5-rc1 points to this patch. This Fedora rawhide container has kernel-headers 6.5.0-0.rc2.git0.1.fc39 and the error disappears when I downgrade to 6.4.0-0.rc7.git0.1.fc39. I have not done a ton of triage/debugging so far, as I am currently hunting down other regressions, but I figured I would get an initial report out, since I noticed it when validating LLVM from the new release/17.x branch. If there is any additional information I can provide or patches I can test, I am more than happy to do so. Cheers, Nathan
