[PATCH v2 14/16] lib: sbi: Configure PMP based on domain memory regions

[Anup Patel]

> -----Original Message-----
> From: Atish Patra <atishp at atishpatra.org>
> Sent: 19 October 2020 05:11
> To: Anup Patel <Anup.Patel at wdc.com>
> Cc: Atish Patra <Atish.Patra at wdc.com>; Alistair Francis
> <Alistair.Francis at wdc.com>; Anup Patel <anup at brainfault.org>; OpenSBI
> <opensbi at lists.infradead.org>
> Subject: Re: [PATCH v2 14/16] lib: sbi: Configure PMP based on domain
> memory regions
> 
> On Thu, Oct 15, 2020 at 6:28 AM Anup Patel <anup.patel at wdc.com> wrote:
> >
> > The PMP configuration on each HART should be only based on the memory
> > regions of the assigned domain. This patch updates the
> > sbi_hart_pmp_configure() function accordingly.
> >
> 
> The commit should be more verbose in explaining that the root domain
> memory region already contains the firmware PMP region. That's why we
> just need to configure the domain memory regions.

Not just root domain, all non-root domains should also have a memory region
to protect the firmware.

I will update the commit description accordingly.

> 
> > Signed-off-by: Anup Patel <anup.patel at wdc.com>
> > ---
> >  lib/sbi/sbi_hart.c | 37 ++++++++++++++++++++++---------------
> >  1 file changed, 22 insertions(+), 15 deletions(-)
> >
> > diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c index
> > ea5d479..1871a1e 100644
> > --- a/lib/sbi/sbi_hart.c
> > +++ b/lib/sbi/sbi_hart.c
> > @@ -13,6 +13,7 @@
> >  #include <sbi/riscv_fp.h>
> >  #include <sbi/sbi_bitops.h>
> >  #include <sbi/sbi_console.h>
> > +#include <sbi/sbi_domain.h>
> >  #include <sbi/sbi_csr_detect.h>
> >  #include <sbi/sbi_error.h>
> >  #include <sbi/sbi_hart.h>
> > @@ -184,24 +185,30 @@ void sbi_hart_pmp_dump(struct sbi_scratch
> > *scratch)
> >
> >  int sbi_hart_pmp_configure(struct sbi_scratch *scratch)  {
> > -       u32 pmp_idx = 0;
> > -       unsigned long fw_start, fw_size_log2;
> > +       struct sbi_domain_memregion *reg;
> > +       struct sbi_domain *dom = sbi_domain_thishart_ptr();
> > +       unsigned int pmp_idx = 0, pmp_flags;
> > +       unsigned int pmp_count = sbi_hart_pmp_count(scratch);
> >
> > -       if (!sbi_hart_pmp_count(scratch))
> > +       if (!pmp_count)
> >                 return 0;
> >
> > -       /* Firmware PMP region to protect OpenSBI firmware */
> > -       fw_size_log2 = log2roundup(scratch->fw_size);
> > -       fw_start = scratch->fw_start & ~((1UL << fw_size_log2) - 1UL);
> > -       pmp_set(pmp_idx++, 0, fw_start, fw_size_log2);
> > -
> > -       /*
> > -        * Default PMP region for allowing S-mode and U-mode access to
> > -        * memory not covered by:
> > -        * 1) Firmware PMP region
> > -        * 2) Platform specific PMP regions
> > -        */
> > -       pmp_set(pmp_idx++, PMP_R | PMP_W | PMP_X, 0, __riscv_xlen);
> > +       sbi_domain_for_each_memregion(dom, reg) {
> > +               if (pmp_count <= pmp_idx)
> > +                       break;
> > +
> > +               pmp_flags = 0;
> > +               if (reg->flags & SBI_DOMAIN_MEMREGION_READABLE)
> > +                       pmp_flags |= PMP_R;
> > +               if (reg->flags & SBI_DOMAIN_MEMREGION_WRITEABLE)
> > +                       pmp_flags |= PMP_W;
> > +               if (reg->flags & SBI_DOMAIN_MEMREGION_EXECUTABLE)
> > +                       pmp_flags |= PMP_X;
> > +               if (reg->flags & SBI_DOMAIN_MEMREGION_MMODE)
> > +                       pmp_flags |= PMP_L;
> > +
> > +               pmp_set(pmp_idx++, pmp_flags, reg->base, reg->order);
> > +       }
> >
> >         return 0;
> >  }
> > --
> > 2.25.1
> >
> >
> > --
> > opensbi mailing list
> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi
> 
> Otherwise, looks good.
> 
> Reviewed-by: Atish Patra <atish.patra at wdc.com>
> 
> --
> Regards,
> Atish

Regards,
Anup