[PATCH v3 1/5] lib: sbi: Remove redundant SBI_HART_HAS_PMP feature

[Anup Patel]

> -----Original Message-----
> From: Atish Patra <atishp at atishpatra.org>
> Sent: 31 August 2020 23:59
> 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 v3 1/5] lib: sbi: Remove redundant SBI_HART_HAS_PMP
> feature
> 
> On Thu, Aug 27, 2020 at 8:40 PM Anup Patel <anup.patel at wdc.com> wrote:
> >
> > The SBI_HART_HAS_PMP feature is redundant because we already have
> > number of PMP regions returned by sbi_hart_pmp_count().
> >
> > Checking whether PMP is supported for a HART can be simply done by
> > checking non-zero value returned by sbi_hart_pmp_count().
> >
> > Signed-off-by: Anup Patel <anup.patel at wdc.com>
> > Reviewed-by: Alistair Francis <alistair.francis at wdc.com>
> > ---
> >  include/sbi/sbi_hart.h    |  8 +++-----
> >  lib/sbi/sbi_hart.c        | 15 +--------------
> >  lib/utils/fdt/fdt_fixup.c |  2 +-
> >  3 files changed, 5 insertions(+), 20 deletions(-)
> >
> > diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h index
> > 51c2c35..c2ea686 100644
> > --- a/include/sbi/sbi_hart.h
> > +++ b/include/sbi/sbi_hart.h
> > @@ -14,14 +14,12 @@
> >
> >  /** Possible feature flags of a hart */  enum sbi_hart_features {
> > -       /** Hart has PMP support */
> > -       SBI_HART_HAS_PMP = (1 << 0),
> >         /** Hart has S-mode counter enable */
> > -       SBI_HART_HAS_SCOUNTEREN = (1 << 1),
> > +       SBI_HART_HAS_SCOUNTEREN = (1 << 0),
> >         /** Hart has M-mode counter enable */
> > -       SBI_HART_HAS_MCOUNTEREN = (1 << 2),
> > +       SBI_HART_HAS_MCOUNTEREN = (1 << 1),
> >         /** HART has timer csr implementation in hardware */
> > -       SBI_HART_HAS_TIME = (1 << 3),
> > +       SBI_HART_HAS_TIME = (1 << 2),
> >
> >         /** Last index of Hart features*/
> >         SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_TIME, diff --git
> > a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c index fa20bd2..80ed86a
> > 100644
> > --- a/lib/sbi/sbi_hart.c
> > +++ b/lib/sbi/sbi_hart.c
> > @@ -158,9 +158,6 @@ void sbi_hart_pmp_dump(struct sbi_scratch
> *scratch)
> >         unsigned long prot, addr, size;
> >         unsigned int i, pmp_count;
> >
> > -       if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_PMP))
> > -               return;
> > -
> >         pmp_count = sbi_hart_pmp_count(scratch);
> >         for (i = 0; i < pmp_count; i++) {
> >                 pmp_get(i, &prot, &addr, &size); @@ -190,9 +187,6 @@
> > int sbi_hart_pmp_check_addr(struct sbi_scratch *scratch, unsigned long
> addr,
> >         unsigned long prot, size, tempaddr;
> >         unsigned int i, pmp_count;
> >
> > -       if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_PMP))
> > -               return SBI_OK;
> > -
> >         pmp_count = sbi_hart_pmp_count(scratch);
> >         for (i = 0; i < pmp_count; i++) {
> >                 pmp_get(i, &prot, &tempaddr, &size); @@ -213,7 +207,7
> > @@ static int pmp_init(struct sbi_scratch *scratch, u32 hartid)
> >         ulong prot, addr, log2size;
> >         const struct sbi_platform *plat = sbi_platform_ptr(scratch);
> >
> > -       if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_PMP))
> > +       if (!sbi_hart_pmp_count(scratch))
> >                 return 0;
> >
> >         /* Firmware PMP region to protect OpenSBI firmware */ @@
> > -276,9 +270,6 @@ static inline char *sbi_hart_feature_id2string(unsigned
> long feature)
> >                 return NULL;
> >
> >         switch (feature) {
> > -       case SBI_HART_HAS_PMP:
> > -               fstr = "pmp";
> > -               break;
> >         case SBI_HART_HAS_SCOUNTEREN:
> >                 fstr = "scounteren";
> >                 break;
> > @@ -375,10 +366,6 @@ static void hart_detect_features(struct sbi_scratch
> *scratch)
> >         __detect_pmp(CSR_PMPADDR15);
> >  #undef __detect_pmp
> >
> > -       /* Set hart PMP feature if we have at least one PMP region */
> > -       if (hfeatures->pmp_count)
> > -               hfeatures->features |= SBI_HART_HAS_PMP;
> > -
> >         /* Detect if hart supports SCOUNTEREN feature */
> >         trap.cause = 0;
> >         val = csr_read_allowed(CSR_SCOUNTEREN, (unsigned long)&trap);
> > diff --git a/lib/utils/fdt/fdt_fixup.c b/lib/utils/fdt/fdt_fixup.c
> > index a3bccae..4da7397 100644
> > --- a/lib/utils/fdt/fdt_fixup.c
> > +++ b/lib/utils/fdt/fdt_fixup.c
> > @@ -199,7 +199,7 @@ int fdt_reserved_memory_fixup(void *fdt)
> >          * With above assumption, we create child nodes directly.
> >          */
> >
> > -       if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_PMP)) {
> > +       if (!sbi_hart_pmp_count(scratch)) {
> >                 /*
> >                  * Update the DT with firmware start & size even if PMP is not
> >                  * supported. This makes sure that supervisor OS is
> > always
> > --
> > 2.25.1
> >
> >
> > --
> > opensbi mailing list
> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi
> 
> 
> Reviewed-by: Atish Patra <atish.patra at wdc.com>

Applied this patch to the riscv/opensbi repo

Regards,
Anup