Re: [RFC v2 11/14] arm64: Move the ASID allocator code in a separate file

[Julien Grall]

On 04/07/2019 15:56, James Morse wrote:
> Hi Julien,

Hi James,

Thank you for the review.

> On 20/06/2019 14:06, Julien Grall wrote:
> > We will want to re-use the ASID allocator in a separate context (e.g
> > allocating VMID). So move the code in a new file.
> >
> > The function asid_check_context has been moved in the header as a static
> > inline function because we want to avoid add a branch when checking if the
> > ASID is still valid.
>
> > diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
> > index 3df63a28856c..b745cf356fe1 100644
> > --- a/arch/arm64/mm/context.c
> > +++ b/arch/arm64/mm/context.c
> > @@ -23,46 +23,21 @@
>
> > -#define ASID_FIRST_VERSION(info)	NUM_ASIDS(info)
>
> > diff --git a/arch/arm64/lib/asid.c b/arch/arm64/lib/asid.c
> > new file mode 100644
> > index 000000000000..7252e4fdd5e9
> > --- /dev/null
> > +++ b/arch/arm64/lib/asid.c
> > @@ -0,0 +1,185 @@
>
> > +#define ASID_FIRST_VERSION(info)	(1UL << ((info)->bits))
>
> (oops!)

Good catch, I will fix it in the next version.

> > @@ -344,7 +115,7 @@ static int asids_init(void)
> >   	if (!asid_allocator_init(&asid_info, bits, ASID_PER_CONTEXT,
> >   				 asid_flush_cpu_ctxt))
> >   		panic("Unable to initialize ASID allocator for %lu ASIDs\n",
> > -		      1UL << bits);
> > +		      NUM_ASIDS(&asid_info));
>
> Could this go in the patch that adds NUM_ASIDS()?

Actually this change is potentially wrong. This relies on asid_allocator_init() 
to set asid_info.bits even if the function fails.

So I think it would be best to keep 1UL << bits here.

Cheers,

--
Julien Grall