linux-kernel - Re: [PATCH v5 06/21] modpost: clean up is_executable

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Message-ID: <CAK7LNAToX+G_9wkmSziU-YZeg9wc2mOGwD-1R-Txrinba4c8RQ@mail.gmail.com>
Date:   Sat, 20 May 2023 22:19:49 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        Nathan Chancellor <nathan@...nel.org>,
        Nicolas Pitre <npitre@...libre.com>,
        Nicolas Schier <nicolas@...sle.eu>
Subject: Re: [PATCH v5 06/21] modpost: clean up is_executable_section()

On Thu, May 18, 2023 at 6:10 AM Nick Desaulniers
<ndesaulniers@...gle.com> wrote:
>
> On Sun, May 14, 2023 at 8:28 AM Masahiro Yamada <masahiroy@...nel.org> wrote:
> >
> > SHF_EXECINSTR is a bit flag (#define SHF_EXECINSTR 0x4).
> > Compare the masked flag to '!= 0'.
> >
> > There is no good reason to stop modpost immediately even if a special
> > section index is given. You will get a section mismatch error anyway.
> >
> > Also, change the return type to bool.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
>
> Moving the definition and renaming the parameter seems very
> unnecessary, but whatever. Thanks for the patch!


Moving the definition _is_ necessary.

See the next patch, which moves the call-site of
is_executable_section().

The definition must come before the caller.



The current code exceeds 80-cols per line.

I renamed the parameters so that the lines
fit within 80-cols without wrapping.





> Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>
>
> > ---
> >
> >  scripts/mod/modpost.c | 16 ++++++++--------
> >  1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> > index bb7d1d87bae7..0bda2f22c985 100644
> > --- a/scripts/mod/modpost.c
> > +++ b/scripts/mod/modpost.c
> > @@ -1207,6 +1207,14 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
> >         return near;
> >  }
> >
> > +static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
> > +{
> > +       if (secndx > elf->num_sections)
> > +               return false;
> > +
> > +       return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
> > +}
> > +
> >  static void default_mismatch_handler(const char *modname, struct elf_info *elf,
> >                                      const struct sectioncheck* const mismatch,
> >                                      Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
> > @@ -1252,14 +1260,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf,
> >         }
> >  }
> >
> > -static int is_executable_section(struct elf_info* elf, unsigned int section_index)
> > -{
> > -       if (section_index > elf->num_sections)
> > -               fatal("section_index is outside elf->num_sections!\n");
> > -
> > -       return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
> > -}
> > -
> >  static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
> >                                      const struct sectioncheck* const mismatch,
> >                                      Elf_Rela* r, Elf_Sym* sym,
> > --
> > 2.39.2
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers



-- 
Best Regards
Masahiro Yamada