Re: [PATCH 03/15] modules: Don't allocate space for non-allocable sections.

From: "Vladimir 'phcoder' Serbinenko" <phcoder@gmail.com>
To: The development of GNU GRUB <grub-devel@gnu.org>
Subject: Re: [PATCH 03/15] modules: Don't allocate space for non-allocable sections.
Date: Fri, 24 May 2024 20:45:04 +0300	[thread overview]
Message-ID: <CAEaD8JPKN48GxDZK1+3BytD1WBOhQGFCr0Kig2-eCuiNGCRugw@mail.gmail.com> (raw)
In-Reply-To: <20240524110402.203880-4-mate.kukri@canonical.com>

Reviewed-By: Vladimir Serbinenko

On Fri, May 24, 2024 at 2:06 PM Mate Kukri <mate.kukri@canonical.com> wrote:
>
> From: Peter Jones <pjones@redhat.com>
>
> Currently when loading grub modules, we allocate space for all sections,
> including those without SHF_ALLOC set.  We then copy the sections that
> /do/ have SHF_ALLOC set into the allocated memory, leaving some of our
> allocation untouched forever.  Additionally, on platforms with GOT
> fixups and trampolines, we currently compute alignment round-ups for the
> sections and sections with sh_size = 0.
>
> This patch removes the extra space from the allocation computation, and
> makes the allocation computation loop skip empty sections as the loading
> loop does.
>
> Signed-off-by: Peter Jones <pjones@redhat.com>
> (cherry picked from commit 0f76b53f2fe86542123c7aa1ae39c90852972a99)
> Signed-off-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
> Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
> ---
>  grub-core/kern/dl.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
> index 0bf40caa6..37db9fab0 100644
> --- a/grub-core/kern/dl.c
> +++ b/grub-core/kern/dl.c
> @@ -237,6 +237,9 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
>         i < e->e_shnum;
>         i++, s = (const Elf_Shdr *)((const char *) s + e->e_shentsize))
>      {
> +      if (s->sh_size == 0 || !(s->sh_flags & SHF_ALLOC))
> +       continue;
> +
>        tsize = ALIGN_UP (tsize, s->sh_addralign) + s->sh_size;
>        if (talign < s->sh_addralign)
>         talign = s->sh_addralign;
> --
> 2.39.2
>
>
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> Grub-devel@gnu.org
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-- 
Regards
Vladimir 'phcoder' Serbinenko

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