[PATCH 05/11] lib: sbi: Remove MCOUNTINHIBT hart feature
Anup Patel
anup at brainfault.org
Fri May 6 22:00:58 PDT 2022
On Wed, May 4, 2022 at 7:26 AM Atish Patra <atishp at atishpatra.org> wrote:
>
> On Fri, Apr 29, 2022 at 8:52 AM Anup Patel <apatel at ventanamicro.com> wrote:
> >
> > If a hart implements privileged spec v1.11 (or higher) then we can
> > safely assume that mcountinhibit CSR is present and we don't need
> > MCOUNTINHIBT as a hart feature.
> >
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > ---
> > include/sbi/sbi_hart.h | 14 ++++++--------
> > lib/sbi/sbi_hart.c | 23 ++++++++---------------
> > lib/sbi/sbi_pmu.c | 10 +++++-----
> > 3 files changed, 19 insertions(+), 28 deletions(-)
> >
> > diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> > index 4665a62..bc6b766 100644
> > --- a/include/sbi/sbi_hart.h
> > +++ b/include/sbi/sbi_hart.h
> > @@ -26,20 +26,18 @@ enum sbi_hart_priv_versions {
> >
> > /** Possible feature flags of a hart */
> > enum sbi_hart_features {
> > - /** Hart has counter inhibit CSR */
> > - SBI_HART_HAS_MCOUNTINHIBIT = (1 << 0),
> > /** Hart has sscofpmf extension */
> > - SBI_HART_HAS_SSCOFPMF = (1 << 1),
> > + SBI_HART_HAS_SSCOFPMF = (1 << 0),
> > /** HART has timer csr implementation in hardware */
> > - SBI_HART_HAS_TIME = (1 << 2),
> > + SBI_HART_HAS_TIME = (1 << 1),
> > /** HART has AIA local interrupt CSRs */
> > - SBI_HART_HAS_AIA = (1 << 3),
> > + SBI_HART_HAS_AIA = (1 << 2),
> > /** HART has menvcfg CSR */
> > - SBI_HART_HAS_MENVCFG = (1 << 4),
> > + SBI_HART_HAS_MENVCFG = (1 << 3),
> > /** HART has mstateen CSR **/
> > - SBI_HART_HAS_SMSTATEEN = (1 << 5),
> > + SBI_HART_HAS_SMSTATEEN = (1 << 4),
> > /** HART has SSTC extension implemented in hardware */
> > - SBI_HART_HAS_SSTC = (1 << 6),
> > + SBI_HART_HAS_SSTC = (1 << 5),
> >
> > /** Last index of Hart features*/
> > SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_SSTC,
> > diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> > index ed8a061..0fe88cb 100644
> > --- a/lib/sbi/sbi_hart.c
> > +++ b/lib/sbi/sbi_hart.c
> > @@ -70,7 +70,7 @@ static void mstatus_init(struct sbi_scratch *scratch)
> > csr_write(CSR_MCOUNTEREN, -1);
> >
> > /* All programmable counters will start running at runtime after S-mode request */
> > - if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
> > + if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_11)
> > csr_write(CSR_MCOUNTINHIBIT, 0xFFFFFFF8);
> >
> > /**
> > @@ -402,9 +402,6 @@ static inline char *sbi_hart_feature_id2string(unsigned long feature)
> > return NULL;
> >
> > switch (feature) {
> > - case SBI_HART_HAS_MCOUNTINHIBIT:
> > - fstr = "mcountinhibit";
> > - break;
> > case SBI_HART_HAS_SSCOFPMF:
> > fstr = "sscofpmf";
> > break;
> > @@ -613,26 +610,22 @@ __mhpm_skip:
> > if (!trap.cause)
> > hfeatures->priv_version = SBI_HART_PRIV_VER_1_10;
> >
> > - /* Detect if hart supports MCOUNTINHIBIT feature */
> > + /* Detect if hart supports Priv v1.11 */
> > val = csr_read_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap);
> > - if (!trap.cause) {
> > - csr_write_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap, val);
> > - if (!trap.cause) {
> > - hfeatures->priv_version = SBI_HART_PRIV_VER_1_11;
> > - hfeatures->features |= SBI_HART_HAS_MCOUNTINHIBIT;
> > - }
> > - }
> > + if (!trap.cause &&
> > + (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_10))
> > + hfeatures->priv_version = SBI_HART_PRIV_VER_1_11;
> >
> > /* Detect if hart has menvcfg CSR */
> > csr_read_allowed(CSR_MENVCFG, (unsigned long)&trap);
> > - if (!trap.cause) {
> > + if (!trap.cause &&
> > + (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_11)) {
> > hfeatures->priv_version = SBI_HART_PRIV_VER_1_12;
> > hfeatures->features |= SBI_HART_HAS_MENVCFG;
> > }
> >
> > /* Counter overflow/filtering is not useful without mcounter/inhibit */
> > - if (hfeatures->features & SBI_HART_HAS_MCOUNTINHIBIT &&
> > - hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
> > + if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
> > /* Detect if hart supports sscofpmf */
> > csr_read_allowed(CSR_SCOUNTOVF, (unsigned long)&trap);
> > if (!trap.cause)
> > diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
> > index 853229e..386bf4d 100644
> > --- a/lib/sbi/sbi_pmu.c
> > +++ b/lib/sbi/sbi_pmu.c
> > @@ -300,7 +300,7 @@ static int pmu_ctr_start_hw(uint32_t cidx, uint64_t ival, bool ival_update)
> > if (cidx > num_hw_ctrs || cidx == 1)
> > return SBI_EINVAL;
> >
> > - if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
> > + if (sbi_hart_priv_version(scratch) < SBI_HART_PRIV_VER_1_11)
> > goto skip_inhibit_update;
> >
> > /*
> > @@ -372,7 +372,7 @@ static int pmu_ctr_stop_hw(uint32_t cidx)
> > struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> > unsigned long mctr_inhbt;
> >
> > - if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
> > + if (sbi_hart_priv_version(scratch) < SBI_HART_PRIV_VER_1_11)
> > return 0;
> >
> > mctr_inhbt = csr_read(CSR_MCOUNTINHIBIT);
> > @@ -524,7 +524,7 @@ static int pmu_ctr_find_hw(unsigned long cbase, unsigned long cmask, unsigned lo
> > !sbi_hart_has_feature(scratch, SBI_HART_HAS_SSCOFPMF))
> > return fixed_ctr;
> >
> > - if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
> > + if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_11)
> > mctr_inhbt = csr_read(CSR_MCOUNTINHIBIT);
> > for (i = 0; i < num_hw_events; i++) {
> > temp = &hw_event_map[i];
> > @@ -551,7 +551,7 @@ static int pmu_ctr_find_hw(unsigned long cbase, unsigned long cmask, unsigned lo
> > if (active_events[hartid][cbase] != SBI_PMU_EVENT_IDX_INVALID)
> > continue;
> > /* If mcountinhibit is supported, the bit must be enabled */
> > - if ((sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT)) &&
> > + if ((sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_11) &&
> > !__test_bit(cbase, &mctr_inhbt))
> > continue;
> > /* We found a valid counter that is not started yet */
> > @@ -726,7 +726,7 @@ void sbi_pmu_exit(struct sbi_scratch *scratch)
> > {
> > u32 hartid = current_hartid();
> >
> > - if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
> > + if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_11)
> > csr_write(CSR_MCOUNTINHIBIT, 0xFFFFFFF8);
> >
> > if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10)
> > --
> > 2.34.1
> >
>
>
> Reviewed-by: Atish Patra <atishp at rivosinc.com>
Applied this patch to the riscv/opensbi repo
Regards,
Anup
> --
> Regards,
> Atish
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