| Message ID | 20250121-x86-use-std-consistently-gcc-15-v1-2-8ab0acf645cb@kernel.org |
|---|---|
| State | Accepted |
| Commit | 8ba14d9f490aef9fd535c04e9e62e1169eb7a055 |
| Headers | show |
| Series | A couple of build fixes for x86 when using GCC 15 | expand |
On Wed, 22 Jan 2025 at 02:12, Nathan Chancellor <nathan@kernel.org> wrote: > > GCC 15 changed the default C standard version to C23, which should not > have impacted the kernel because it requests the gnu11 standard via > '-std=' in the main Makefile. However, the EFI libstub Makefile uses its > own set of KBUILD_CFLAGS for x86 without a '-std=' value (i.e., using > the default), resulting in errors from the kernel's definitions of bool, > true, and false in stddef.h, which are reserved keywords under C23. > > ./include/linux/stddef.h:11:9: error: expected identifier before ‘false’ > 11 | false = 0, > ./include/linux/types.h:35:33: error: two or more data types in declaration specifiers > 35 | typedef _Bool bool; > > Set '-std=gnu11' in the x86 cflags to resolve the error and consistently > use the same C standard version for the entire kernel. All other > architectures reuse KBUILD_CFLAGS from the rest of the kernel, so this > issue is not visible for them. > > Cc: stable@vger.kernel.org > Reported-by: Kostadin Shishmanov <kostadinshishmanov@protonmail.com> > Closes: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvduultkgfAIRZI3vQpZylu7Gl929HaYFRGeMEalWCpeMzCIIhLxxRhq4U-Y=@protonmail.com/ > Reported-by: Jakub Jelinek <jakub@redhat.com> > Closes: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/ > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > drivers/firmware/efi/libstub/Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile > index ed4e8ddbe76a..1141cd06011f 100644 > --- a/drivers/firmware/efi/libstub/Makefile > +++ b/drivers/firmware/efi/libstub/Makefile > @@ -11,7 +11,7 @@ cflags-y := $(KBUILD_CFLAGS) > > cflags-$(CONFIG_X86_32) := -march=i386 > cflags-$(CONFIG_X86_64) := -mcmodel=small > -cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \ > +cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -std=gnu11 \ > -fPIC -fno-strict-aliasing -mno-red-zone \ > -mno-mmx -mno-sse -fshort-wchar \ > -Wno-pointer-sign \ > Thanks - I'll add this one to the EFI pile.
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index ed4e8ddbe76a..1141cd06011f 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -11,7 +11,7 @@ cflags-y := $(KBUILD_CFLAGS) cflags-$(CONFIG_X86_32) := -march=i386 cflags-$(CONFIG_X86_64) := -mcmodel=small -cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \ +cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -std=gnu11 \ -fPIC -fno-strict-aliasing -mno-red-zone \ -mno-mmx -mno-sse -fshort-wchar \ -Wno-pointer-sign \
GCC 15 changed the default C standard version to C23, which should not have impacted the kernel because it requests the gnu11 standard via '-std=' in the main Makefile. However, the EFI libstub Makefile uses its own set of KBUILD_CFLAGS for x86 without a '-std=' value (i.e., using the default), resulting in errors from the kernel's definitions of bool, true, and false in stddef.h, which are reserved keywords under C23. ./include/linux/stddef.h:11:9: error: expected identifier before ‘false’ 11 | false = 0, ./include/linux/types.h:35:33: error: two or more data types in declaration specifiers 35 | typedef _Bool bool; Set '-std=gnu11' in the x86 cflags to resolve the error and consistently use the same C standard version for the entire kernel. All other architectures reuse KBUILD_CFLAGS from the rest of the kernel, so this issue is not visible for them. Cc: stable@vger.kernel.org Reported-by: Kostadin Shishmanov <kostadinshishmanov@protonmail.com> Closes: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvduultkgfAIRZI3vQpZylu7Gl929HaYFRGeMEalWCpeMzCIIhLxxRhq4U-Y=@protonmail.com/ Reported-by: Jakub Jelinek <jakub@redhat.com> Closes: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/ Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- drivers/firmware/efi/libstub/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)