Re: [PATCH v2 12/18] arm64: entry: Explicitly pass exception level to kernel_ventry macro

From: Mark Rutland
Date: Fri Dec 01 2017 - 13:00:58 EST


On Fri, Dec 01, 2017 at 05:51:44PM +0000, Will Deacon wrote:
> On Fri, Dec 01, 2017 at 11:58:36AM +0000, Mark Rutland wrote:
> > On Thu, Nov 30, 2017 at 04:39:40PM +0000, Will Deacon wrote:

> > > + .macro kernel_ventry, el, label, regsize = 64

> > > + b el\()\el\()_\label

> > > - kernel_ventry el1_sync_invalid // Synchronous EL1t

> > > + kernel_ventry 1, sync_invalid // Synchronous EL1t

> > Using the el paramter to build the branch name has the unfortunate
> > property of obscuring the branch name. For example, that makes it
> > difficult to jump around the entry asm with ctags, which is somewhat
> > painful.
> >
> > Could we leave the full branch name in place, e.g.
> >
> > kernel_ventry 1, el1_sync_invalid // Synchronous EL1t
> > kernel_ventry 1, el1_irq_invalid // IRQ EL1t
> > kernel_ventry 1, el1_fiq_invalid // FIQ EL1t
> > kernel_ventry 1, el1_error_invalid // Error EL1t
> >
> > ... or have separate kernel_ventry and user_ventry macros that
> > implicitly encoded the source EL, also leaving the label name as-is.
>
> The downside of doing that is that it makes it possible to say things like:
>
> kernel_ventry 0, el1_sync
>
> which I don't want to be expressible.
>
> Given that ctags already chokes on lots of entry.S (for example, any macro
> that is defined outside of the file) *and* that you can easily search for
> things like el1_sync_invalid within the file, I'm inclined to leave this
> patch as-is, but I'll note your objection and buy you a pint.

I guess I'll live with it, then. ;)

Assuming I can't twist your arm, feel free to take my Reviewed-by here
too.

Thanks,
Mark.