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

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

On Thu, Nov 08, 2018 at 11:57:27AM +0000, Julien Thierry wrote:
> 
> 
> On 08/11/18 10:16, Mark Rutland wrote:
> > On Wed, Nov 07, 2018 at 09:58:35PM +0000, Will Deacon wrote:
> > > 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 :/
> > 
> > Perhaps asm-offsets.c, when we define S_FRAME_SIZE?
> > 
> 
> That sounds like a good option to me. If Will thinks so as well I'll move
> that in asm-offsets.c.

Fine by me.

Will