lkml.org 
[lkml]   [2020]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v4 14/17] arm/build: Warn on orphan section placement
On Sun, Jun 28, 2020 at 11:18 PM Kees Cook <keescook@chromium.org> wrote:
>
> We don't want to depend on the linker's orphan section placement
> heuristics as these can vary between linkers, and may change between
> versions. All sections need to be explicitly named in the linker
> script.
>
> Specifically, this would have made a recently fixed bug very obvious:
>
> ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup'
>
> Discard unneeded sections .iplt, .rel.iplt, .igot.plt, and .modinfo.
>
> Add missing text stub sections .vfp11_veneer and .v4_bx.
>
> Add debug sections explicitly.
>
> Finally enable orphan section warning.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>

Thanks for following up on the previous suggestion regarding .glu_7 /
.glu_7t ordering. LGTM
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
> arch/arm/include/asm/vmlinux.lds.h | 6 +++++-
> arch/arm/kernel/vmlinux-xip.lds.S | 1 +
> arch/arm/kernel/vmlinux.lds.S | 1 +
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h
> index c66b16cd8837..d44fae722e7a 100644
> --- a/arch/arm/include/asm/vmlinux.lds.h
> +++ b/arch/arm/include/asm/vmlinux.lds.h
> @@ -39,6 +39,8 @@
> __idmap_text_end = .; \
>
> #define ARM_COMMON_DISCARD \
> + *(.iplt) *(.rel.iplt) *(.igot.plt) \
> + *(.modinfo) \
> *(.discard) \
> *(.discard.*)
>
> @@ -63,7 +65,9 @@
> #define ARM_STUBS_TEXT \
> *(.gnu.warning) \
> *(.glue_7) \
> - *(.glue_7t)
> + *(.glue_7t) \
> + *(.vfp11_veneer) \
> + *(.v4_bx)
>
> #define ARM_TEXT \
> IDMAP_TEXT \
> diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S
> index 57fcbf55f913..11ffa79751da 100644
> --- a/arch/arm/kernel/vmlinux-xip.lds.S
> +++ b/arch/arm/kernel/vmlinux-xip.lds.S
> @@ -150,6 +150,7 @@ SECTIONS
> _end = .;
>
> STABS_DEBUG
> + DWARF_DEBUG
> ARM_DETAILS
> }
>
> diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
> index 1d3d3b599635..dc672fe35de3 100644
> --- a/arch/arm/kernel/vmlinux.lds.S
> +++ b/arch/arm/kernel/vmlinux.lds.S
> @@ -149,6 +149,7 @@ SECTIONS
> _end = .;
>
> STABS_DEBUG
> + DWARF_DEBUG
> ARM_DETAILS
> }
>
> --
> 2.25.1
>
> --
> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20200629061840.4065483-15-keescook%40chromium.org.



--
Thanks,
~Nick Desaulniers

\
 
 \ /
  Last update: 2020-06-29 21:49    [W:0.147 / U:0.732 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site