Re: [PATCH v2 2/3] arm64: mm: Handle PAN faults on uaccess CPY* instructions

[Catalin Marinas <catalin.marinas@arm.com>]

On Fri, Mar 07, 2025 at 06:53:37PM +0000, Robin Murphy wrote:
> On 2025-03-07 6:45 pm, Catalin Marinas wrote:
> > On Fri, Feb 28, 2025 at 05:00:05PM +0000, Kristina Martsenko wrote:
> > > +bool extable_insn_may_access_user(const struct exception_table_entry *ex,
> > > +				  unsigned long esr)
> > > +{
> > > +	switch (ex->type) {
> > > +	case EX_TYPE_UACCESS_CPY:
> > > +		return cpy_faulted_on_uaccess(ex, esr);
> > > +	default:
> > > +		return true;
> > > +	}
> > > +}
> > 
> > Not a problem with this patch but I wonder whether we should return
> > false for EX_TYPE_LOAD_UNALIGNED_ZEROPAD for completeness
> 
> Or maybe rather, true for EX_TYPE_UACCESS_ERR_ZERO and then false in the
> default case?

Yes.

> > (and remove
> > the EX_TYPE_KACCESS_ERR_ZERO, it's no longer used.
> 
> I think that's just hidden in the macro swamp of
> __get_mem_asm()/__put_mem_asm()...

Ah, you are right. I now recall I found them about a year ago but forgot
since.

-- 
Catalin