+CC: clang-built-linux list, Fangrui
On Mon, Jan 22, 2024 at 1:04 PM Aiden Leong <aiden.leong@xxxxxxxxx> wrote:
>
>
> > The function fatal() never returns because modpost_log() calls exit(1)
>
> > when LOG_FATAL is passed.
> >
> > Inform compilers of this fact so that unreachable code flow can be
> > identified at compile time.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> > ---
> >
> > Changes in v2:
> > - Use noreturn attribute together with alias
> >
> > scripts/mod/modpost.c | 3 +++
> > scripts/mod/modpost.h | 5 ++++-
> > 2 files changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> > index ca0a90158f85..c13bc9095df3 100644
> > --- a/scripts/mod/modpost.c
> > +++ b/scripts/mod/modpost.c
> > @@ -90,6 +90,9 @@ void modpost_log(enum loglevel loglevel, const char
> *fmt, ...)
> > error_occurred = true;
> > }
> >
> > +void __attribute__((alias("modpost_log")))
>
> Hi Masahiro,
> I cross-compile kernel on Apple Silicon MacBook Pro
> and every thing works well until this patch.
>
> My build command:
> make ARCH=arm CROSS_COMPILE=arm-none-eabi- \
> HOSTCFLAGS="-I/opt/homebrew/opt/openssl/include" \
> HOSTLDFLAGS="-L/opt/homebrew/opt/openssl/lib"
>
> Error message:
> scripts/mod/modpost.c:93:21: error: aliases are not supported on darwin
It is unfortunate. Indeed, I see this message in:
clang/include/clang/Basic/DiagnosticSemaKinds.td
Is this limitation due to macOS executable (PEF),
or is it Clang-specific?
Perhaps, "brew install gcc" can be a solution?
>
> Aiden Leong
>
> > +modpost_log_noret(enum loglevel loglevel, const char *fmt, ...);
> > +
> > static inline bool strends(const char *str, const char *postfix)
> > {
> > if (strlen(str) < strlen(postfix))
> > diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
> > index 9fe974dc1a52..835cababf1b0 100644
> > --- a/scripts/mod/modpost.h
> > +++ b/scripts/mod/modpost.h
> > @@ -200,6 +200,9 @@ enum loglevel {
> > void __attribute__((format(printf, 2, 3)))
> > modpost_log(enum loglevel loglevel, const char *fmt, ...);
> >
> > +void __attribute__((format(printf, 2, 3), noreturn))
> > +modpost_log_noret(enum loglevel loglevel, const char *fmt, ...);
> > +
> > /*
> > * warn - show the given message, then let modpost continue running,
> still
> > * allowing modpost to exit successfully. This should be used
> when
> > @@ -215,4 +218,4 @@ modpost_log(enum loglevel loglevel, const char
> *fmt, ...);
> > */
> > #define warn(fmt, args...) modpost_log(LOG_WARN, fmt, ##args)
> > #define error(fmt, args...) modpost_log(LOG_ERROR, fmt, ##args)
> > -#define fatal(fmt, args...) modpost_log(LOG_FATAL, fmt, ##args)
> > +#define fatal(fmt, args...) modpost_log_noret(LOG_FATAL, fmt, ##args)
> > --
> > 2.40.1
--
Best Regards
Masahiro Yamada
