Messages in this thread | | | Date | Thu, 17 Aug 2023 13:13:04 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH] Compiler Attributes: counted_by: Adjust name and identifier expansion |
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On Thu, Aug 17, 2023 at 01:06:03PM -0700, Kees Cook wrote: > GCC and Clang's current RFCs name this attribute "counted_by", and have > moved away from using a string for the member name. Update the kernel's > macros to match. Additionally provide a UAPI no-op macro for UAPI structs > that will gain annotations. > > Cc: Miguel Ojeda <ojeda@kernel.org> > Cc: Nick Desaulniers <ndesaulniers@google.com> > Fixes: dd06e72e68bc ("Compiler Attributes: Add __counted_by macro") > Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
One comment below.
> --- > include/linux/compiler_attributes.h | 26 +++++++++++++------------- > include/uapi/linux/stddef.h | 4 ++++ > 2 files changed, 17 insertions(+), 13 deletions(-) > > diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h > index 00efa35c350f..74716a407aac 100644 > --- a/include/linux/compiler_attributes.h > +++ b/include/linux/compiler_attributes.h > @@ -94,6 +94,19 @@ > # define __copy(symbol) > #endif > > +/* > + * Optional: only supported since gcc >= 14 > + * Optional: only supported since clang >= 17
Since you are in the area, should the supported clang version be optimistically updated to '18'? 17.x has already branched and I suspect it would be too late in the release cycle to cherry-pick that change from main if it were landed today (which seems pretty unlikely, given there do not appear to be many reviews from high profile clang folks yet).
> + * > + * gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 > + * clang: https://reviews.llvm.org/D148381 > + */ > +#if __has_attribute(__counted_by__) > +# define __counted_by(member) __attribute__((__counted_by__(member))) > +#else > +# define __counted_by(member) > +#endif > + > /* > * Optional: not supported by gcc > * Optional: only supported since clang >= 14.0 > @@ -129,19 +142,6 @@ > # define __designated_init > #endif > > -/* > - * Optional: only supported since gcc >= 14 > - * Optional: only supported since clang >= 17 > - * > - * gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 > - * clang: https://reviews.llvm.org/D148381 > - */ > -#if __has_attribute(__element_count__) > -# define __counted_by(member) __attribute__((__element_count__(#member))) > -#else > -# define __counted_by(member) > -#endif > - > /* > * Optional: only supported since clang >= 14.0 > * > diff --git a/include/uapi/linux/stddef.h b/include/uapi/linux/stddef.h > index 7837ba4fe728..7c3fc3980881 100644 > --- a/include/uapi/linux/stddef.h > +++ b/include/uapi/linux/stddef.h > @@ -45,3 +45,7 @@ > TYPE NAME[]; \ > } > #endif > + > +#ifndef __counted_by > +#define __counted_by(m) > +#endif > -- > 2.34.1 >
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