linux-kernel - Re: [PATCH] powerpc/module_64: use module_init

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Message-ID: <CAMKQLN+Q3asVqP3MZVFZO66CvZVVfGOZn=pMXmiNqZ7t2i55wg@mail.gmail.com>
Date:   Tue, 15 Feb 2022 01:49:39 +0000
From:   Wedson Almeida Filho <wedsonaf@...gle.com>
To:     Michael Ellerman <mpe@...erman.id.au>
Cc:     benh@...nel.crashing.org, paulus@...ba.org,
        linuxppc-dev@...ts.ozlabs.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] powerpc/module_64: use module_init_section instead of
 patching names

Hi Michael,

On Wed, 2 Feb 2022 at 05:53, Wedson Almeida Filho <wedsonaf@...gle.com> wrote:
>
> Without this patch, module init sections are disabled by patching their
> names in arch-specific code when they're loaded (which prevents code in
> layout_sections from finding init sections). This patch uses the new
> arch-specific module_init_section instead.
>
> This allows modules that have .init_array sections to have the
> initialisers properly called (on load, before init). Without this patch,
> the initialisers are not called because .init_array is renamed to
> _init_array, and thus isn't found by code in find_module_sections().
>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@...gle.com>
> ---
>  arch/powerpc/kernel/module_64.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
> index 5d77d3f5fbb5..6a45e6ddbe58 100644
> --- a/arch/powerpc/kernel/module_64.c
> +++ b/arch/powerpc/kernel/module_64.c
> @@ -277,6 +277,12 @@ static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
>         return NULL;
>  }
>
> +bool module_init_section(const char *name)
> +{
> +       /* We don't handle .init for the moment: always return false. */
> +       return false;
> +}
> +
>  int module_frob_arch_sections(Elf64_Ehdr *hdr,
>                               Elf64_Shdr *sechdrs,
>                               char *secstrings,
> @@ -286,7 +292,6 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr,
>
>         /* Find .toc and .stubs sections, symtab and strtab */
>         for (i = 1; i < hdr->e_shnum; i++) {
> -               char *p;
>                 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
>                         me->arch.stubs_section = i;
>                 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
> @@ -298,10 +303,6 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr,
>                         dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
>                                           sechdrs[i].sh_size);
>
> -               /* We don't handle .init for the moment: rename to _init */
> -               while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
> -                       p[0] = '_';
> -
>                 if (sechdrs[i].sh_type == SHT_SYMTAB)
>                         dedotify((void *)hdr + sechdrs[i].sh_offset,
>                                  sechdrs[i].sh_size / sizeof(Elf64_Sym),
> --
> 2.35.0.rc2.247.g8bbb082509-goog

Would any additional clarification from my part be helpful here?

I got an email saying it was under review (and checks passed) but
nothing appears to have happened since.

Cheers,
-Wedson