[PATCH v5 2/7] lib: sbi: Narrow vendor extension range

[Andrew Jones]

On Mon, May 15, 2023 at 04:02:01PM +0530, Anup Patel wrote:
> On Mon, May 15, 2023 at 3:04 PM Andrew Jones <ajones at ventanamicro.com> wrote:
> >
> > The vendor extension ID range is large, but at runtime at most
> > a single ID will be available. Narrow the range in the
> > register_extensions callback. After narrowing, we no longer
> > need to check that the extension ID is correct in the other
> > callbacks, as those callbacks will never be invoked with
> > anything other than the single ID.
> >
> > Signed-off-by: Andrew Jones <ajones at ventanamicro.com>
> > ---
> >  lib/sbi/sbi_ecall_vendor.c | 11 +++++++----
> >  1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/lib/sbi/sbi_ecall_vendor.c b/lib/sbi/sbi_ecall_vendor.c
> > index 126156f79a12..39c58c8b6fd5 100644
> > --- a/lib/sbi/sbi_ecall_vendor.c
> > +++ b/lib/sbi/sbi_ecall_vendor.c
> > @@ -25,8 +25,7 @@ static inline unsigned long sbi_ecall_vendor_id(void)
> >  static int sbi_ecall_vendor_probe(unsigned long extid,
> >                                   unsigned long *out_val)
> >  {
> > -       if (!sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr()) ||
> > -           extid != sbi_ecall_vendor_id())
> > +       if (!sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr()))
> >                 *out_val = 0;
> >         else
> >                 *out_val = 1;
> > @@ -38,8 +37,7 @@ static int sbi_ecall_vendor_handler(unsigned long extid, unsigned long funcid,
> >                                     unsigned long *out_val,
> >                                     struct sbi_trap_info *out_trap)
> >  {
> > -       if (!sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr()) ||
> > -           extid != sbi_ecall_vendor_id())
> > +       if (!sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr()))
> >                 return SBI_ERR_NOT_SUPPORTED;
> >
> >         return sbi_platform_vendor_ext_provider(sbi_platform_thishart_ptr(),
> > @@ -51,6 +49,11 @@ struct sbi_ecall_extension ecall_vendor;
> >
> >  static int sbi_ecall_vendor_register_extensions(void)
> >  {
> > +       unsigned long extid = sbi_ecall_vendor_id();
> > +
> > +       ecall_vendor.extid_start = extid;
> > +       ecall_vendor.extid_end = extid;
> > +
> >         return sbi_ecall_register_extension(&ecall_vendor);
> 
> Actually, we should register vendor extension only if
> sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr())
> is true.

That's done in a later patch.

> 
> This way we can remove the if-check from
> sbi_ecall_vendor_handler() and
> sbi_ecall_vendor_probe().

The extid != sbi_ecall_vendor_id part can be / is removed in this patch,
but I forgot to remove the other part in the later patch after adding
it to sbi_ecall_vendor_register_extensions(). I'll do that for v6.

Thanks,
drew