[PATCH 1/7] arm64: Add static check for pt_regs alignment

[will.deacon@arm.com (Will Deacon)]

On Wed, Sep 26, 2018 at 02:56:18PM +0100, Julien Thierry wrote:
> The pt_regs structure's size is required to be a multiple of 16 to maintain
> the stack alignment upon kernel entries.
> 
> Add a static check to ensure this is the case.
> 
> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
> ---
>  arch/arm64/include/asm/ptrace.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> index 177b851..cc17fad 100644
> --- a/arch/arm64/include/asm/ptrace.h
> +++ b/arch/arm64/include/asm/ptrace.h
> @@ -229,6 +229,8 @@ static inline u64 regs_get_register(struct pt_regs *regs, unsigned int offset)
>  
>  	WARN_ON(offset & 7);
>  
> +	BUILD_BUG_ON((sizeof (struct pt_regs) % 16 != 0));

This seems like a fairly random place to put this, and given that it's not
dependent on context I reckon it would be better to put it in a C file
rather than in a header that gets included multiple times. I still couldn't
really find a good place though :/

Will