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References: <20230514152739.962109-1-masahiroy@kernel.org> <20230514152739.962109-5-masahiroy@kernel.org>
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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Wed, 17 May 2023 14:27:02 -0700
Message-ID: <CAKwvOd=ntBEuLMyw55U3=mZmJ8=JY_NhiBL0nO9RtU8t6m+=VQ@mail.gmail.com>
Subject: Re: [PATCH v5 04/21] modpost: squash report_extable_warnings() into extable_mismatch_handler()
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nicolas Pitre <npitre@baylibre.com>,
        Nicolas Schier <nicolas@fjasle.eu>
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On Sun, May 14, 2023 at 8:27=E2=80=AFAM Masahiro Yamada <masahiroy@kernel.o=
rg> wrote:
>
> Collect relevant code into one place to clarify all the cases are
> covered by 'if () ... else if ... else ...'.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>
>  scripts/mod/modpost.c | 40 ++++++++++++++--------------------------
>  1 file changed, 14 insertions(+), 26 deletions(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 371891d67175..7a9a3ef8ca0d 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -1275,40 +1275,19 @@ static int is_executable_section(struct elf_info*=
 elf, unsigned int section_inde
>         return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) =
=3D=3D SHF_EXECINSTR);
>  }
>
> -static void report_extable_warnings(const char* modname, struct elf_info=
* elf,
> -                                   const struct sectioncheck* const mism=
atch,
> -                                   Elf_Rela* r, Elf_Sym* sym,
> -                                   const char* fromsec, const char* tose=
c)
> -{
> -       Elf_Sym* tosym =3D find_elf_symbol(elf, r->r_addend, sym);
> -       const char* tosym_name =3D sym_name(elf, tosym);
> -
> -       warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n"=
,
> -            modname, fromsec, (long)r->r_offset, tosec, tosym_name);
> -
> -       if (!match(tosec, mismatch->bad_tosec) &&
> -           is_executable_section(elf, get_secindex(elf, sym)))
> -               fprintf(stderr,
> -                       "The relocation at %s+0x%lx references\n"
> -                       "section \"%s\" which is not in the list of\n"
> -                       "authorized sections.  If you're adding a new sec=
tion\n"
> -                       "and/or if this reference is valid, add \"%s\" to=
 the\n"
> -                       "list of authorized sections to jump to on fault.=
\n"
> -                       "This can be achieved by adding \"%s\" to \n"
> -                       "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n"=
,
> -                       fromsec, (long)r->r_offset, tosec, tosec, tosec);
> -}
> -
>  static void extable_mismatch_handler(const char* modname, struct elf_inf=
o *elf,
>                                      const struct sectioncheck* const mis=
match,
>                                      Elf_Rela* r, Elf_Sym* sym,
>                                      const char *fromsec)
>  {
>         const char* tosec =3D sec_name(elf, get_secindex(elf, sym));
> +       Elf_Sym *tosym =3D find_elf_symbol(elf, r->r_addend, sym);
> +       const char *tosym_name =3D sym_name(elf, tosym);
>
>         sec_mismatch_count++;
>
> -       report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, =
tosec);
> +       warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n"=
,
> +            modname, fromsec, (long)r->r_offset, tosec, tosym_name);
>
>         if (match(tosec, mismatch->bad_tosec))
>                 fatal("The relocation at %s+0x%lx references\n"
> @@ -1317,7 +1296,16 @@ static void extable_mismatch_handler(const char* m=
odname, struct elf_info *elf,
>                       "You might get more information about where this is=
\n"
>                       "coming from by using scripts/check_extable.sh %s\n=
",
>                       fromsec, (long)r->r_offset, tosec, modname);
> -       else if (!is_executable_section(elf, get_secindex(elf, sym)))
> +       else if (is_executable_section(elf, get_secindex(elf, sym)))
> +               warn("The relocation at %s+0x%lx references\n"
> +                    "section \"%s\" which is not in the list of\n"
> +                    "authorized sections.  If you're adding a new sectio=
n\n"
> +                    "and/or if this reference is valid, add \"%s\" to th=
e\n"
> +                    "list of authorized sections to jump to on fault.\n"
> +                    "This can be achieved by adding \"%s\" to\n"
> +                    "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
> +                    fromsec, (long)r->r_offset, tosec, tosec, tosec);
> +       else
>                 error("%s+0x%lx references non-executable section '%s'\n"=
,
>                       fromsec, (long)r->r_offset, tosec);
>  }
> --
> 2.39.2
>


--=20
Thanks,
~Nick Desaulniers