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SubjectRe: [PATCH 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
On Thu, Sep 26, 2019 at 10:55:47AM -0700, Kees Cook wrote:
> Many architectures have an EXCEPTION_TABLE that needs only to be
> read-only. As such, it should live in RO_DATA. This creates a macro to
> identify this case for the architectures that can move EXCEPTION_TABLE
> into RO_DATA.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> include/asm-generic/vmlinux.lds.h | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index d57a28786bb8..35a6cba39d9f 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -69,6 +69,17 @@
> #define NOTES_HEADERS_RESTORE
> #endif
>
> +/*
> + * Some architectures have non-executable read-only exception tables.
> + * They can be added to the RO_DATA segment by specifying their desired
> + * alignment.
> + */
> +#ifdef RO_DATA_EXCEPTION_TABLE_ALIGN
> +#define RO_DATA_EXCEPTION_TABLE EXCEPTION_TABLE(RO_DATA_EXCEPTION_TABLE_ALIGN)
> +#else
> +#define RO_DATA_EXCEPTION_TABLE
> +#endif
> +
> /* Align . to a 8 byte boundary equals to maximum function alignment. */
> #define ALIGN_FUNCTION() . = ALIGN(8)
>
> @@ -508,6 +519,7 @@
> __stop___modver = .; \
> } \
> \
> + RO_DATA_EXCEPTION_TABLE \
> NOTES \
> \
> . = ALIGN((align)); \
> --

I think you can drop the "DATA" from the names as it is kinda clear
where the exception table lands:

RO_EXCEPTION_TABLE_ALIGN
RO_EXCEPTION_TABLE

The "read-only" part is the important one.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

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