[PATCH v6 09/15] arm64: reserve x18 from general allocation with SCS

Will Deacon will at kernel.org
Thu Jan 16 09:37:40 PST 2020

On Fri, Dec 06, 2019 at 02:13:45PM -0800, Sami Tolvanen wrote:
> Reserve the x18 register from general allocation when SCS is enabled,
> because the compiler uses the register to store the current task's
> shadow stack pointer. Note that all external kernel modules must also be
> compiled with -ffixed-x18 if the kernel has SCS enabled.
> Signed-off-by: Sami Tolvanen <samitolvanen at google.com>
> Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>
> Reviewed-by: Kees Cook <keescook at chromium.org>
> ---
>  arch/arm64/Makefile | 4 ++++
>  1 file changed, 4 insertions(+)

Acked-by: Will Deacon <will at kernel.org>


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