Re: [PATCH v3 5/5] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

[David Long]

On 11/18/14 09:52, Will Deacon wrote:
> Hi David,
>
> On Tue, Nov 18, 2014 at 06:32:55AM +0000, David Long wrote:
> > From: "David A. Long" <dave.long@xxxxxxxxxx>
> >
> > Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.
>
> [...]
>
> > diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> > index d3e782a..24cc048 100644
> > --- a/arch/arm64/include/asm/ptrace.h
> > +++ b/arch/arm64/include/asm/ptrace.h
> > @@ -111,6 +111,8 @@ struct pt_regs {
> >   	u64 syscallno;
> >   };
> >
> > +#define MAX_REG_OFFSET (offsetof(struct pt_regs, orig_x0))
>
> Is orig_x0 actually useful to this API? If not, we could instead operate on
> the user_pt_regs structure, and define the maximum offset in terms of sizeof
> that.

I agree.  I don't think the orig_x0 field should be exposed through this 
API.

> > +#define ARM_cpsr	pstate
> > +#define ARM_pc		pc
> > +#define ARM_sp		sp
> > +#define ARM_lr		regs[30]
> > +#define ARM_fp		regs[29]
> > +#define ARM_x28		regs[28]
> > +#define ARM_x27		regs[27]
>
> [...]
>
> I don't think we need these #defines.
>
> Will

These are used in the REG_OFFSET_NAME macro.  This is all borrowed from 
arch/arm/ code.  I didn't see a need to redesign it.

-dl


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