On Tue, Mar 01, 2022 at 03:52:33PM +0100, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@xxxxxxxx> > > As we change the C language standard for the kernel from gnu89 to > gnu11, it makes sense to also update the version for user space > compilation. > > Some users have older native compilers than what they use for > kernel builds, so I considered using gnu99 as the default version > for wider compatibility with gcc-4.6 and earlier. > > However, testing with older compilers showed that we already require > HOSTCC version 5.1 as well because a lot of host tools include > linux/compiler.h that uses __has_attribute(): > > CC tools/objtool/exec-cmd.o > In file included from tools/include/linux/compiler_types.h:36:0, > from tools/include/linux/compiler.h:5, > from exec-cmd.c:2: > tools/include/linux/compiler-gcc.h:19:5: error: "__has_attribute" is not defined [-Werror=undef] For what it's worth, I think this is a bug: https://lore.kernel.org/r/c1b1a299-c60d-28a4-07ab-1ecd211d6da9@xxxxxxxxxxxxxxxxxxx/ https://lore.kernel.org/r/20220102120201.594408-1-xu.xin16@xxxxxxxxxx/ I never got clear feedback on resolving it from the first thread and nobody bothered to pick up the second patch. > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Nobody has yelled that loud though, so this is probably fine. Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> > --- > Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/Makefile b/Makefile > index 37ef6a555dcd..7c9be7f1ccd4 100644 > --- a/Makefile > +++ b/Makefile > @@ -432,7 +432,7 @@ HOSTCXX = g++ > endif > > export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ > - -O2 -fomit-frame-pointer -std=gnu89 \ > + -O2 -fomit-frame-pointer -std=gnu11 \ > -Wdeclaration-after-statement > export KBUILD_USERLDFLAGS := > > -- > 2.29.2 > >
