[PATCH 04/11] lib: sbi: Remove MCOUNTEREN and SCOUNTEREN hart features
Anup Patel
anup at brainfault.org
Fri May 6 22:00:30 PDT 2022
On Wed, May 4, 2022 at 7:21 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 v1.10 (or higher) then we can
> > safely assume that [m|s]counteren CSR are present and we don't need
> > MCOUNTEREN and SCOUNTEREN as hart features.
> >
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > ---
> > include/sbi/sbi_hart.h | 18 +++++++-----------
> > lib/sbi/sbi_emulate_csr.c | 4 ++--
> > lib/sbi/sbi_hart.c | 29 +++++------------------------
> > lib/sbi/sbi_pmu.c | 3 ++-
> > 4 files changed, 16 insertions(+), 38 deletions(-)
> >
> > diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> > index 3c37933..4665a62 100644
> > --- a/include/sbi/sbi_hart.h
> > +++ b/include/sbi/sbi_hart.h
> > @@ -26,24 +26,20 @@ enum sbi_hart_priv_versions {
> >
> > /** Possible feature flags of a hart */
> > enum sbi_hart_features {
> > - /** Hart has S-mode counter enable */
> > - SBI_HART_HAS_SCOUNTEREN = (1 << 0),
> > - /** Hart has M-mode counter enable */
> > - SBI_HART_HAS_MCOUNTEREN = (1 << 1),
> > /** Hart has counter inhibit CSR */
> > - SBI_HART_HAS_MCOUNTINHIBIT = (1 << 2),
> > + SBI_HART_HAS_MCOUNTINHIBIT = (1 << 0),
> > /** Hart has sscofpmf extension */
> > - SBI_HART_HAS_SSCOFPMF = (1 << 3),
> > + SBI_HART_HAS_SSCOFPMF = (1 << 1),
> > /** HART has timer csr implementation in hardware */
> > - SBI_HART_HAS_TIME = (1 << 4),
> > + SBI_HART_HAS_TIME = (1 << 2),
> > /** HART has AIA local interrupt CSRs */
> > - SBI_HART_HAS_AIA = (1 << 5),
> > + SBI_HART_HAS_AIA = (1 << 3),
> > /** HART has menvcfg CSR */
> > - SBI_HART_HAS_MENVCFG = (1 << 6),
> > + SBI_HART_HAS_MENVCFG = (1 << 4),
> > /** HART has mstateen CSR **/
> > - SBI_HART_HAS_SMSTATEEN = (1 << 7),
> > + SBI_HART_HAS_SMSTATEEN = (1 << 5),
> > /** HART has SSTC extension implemented in hardware */
> > - SBI_HART_HAS_SSTC = (1 << 8),
> > + SBI_HART_HAS_SSTC = (1 << 6),
> >
> > /** Last index of Hart features*/
> > SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_SSTC,
> > diff --git a/lib/sbi/sbi_emulate_csr.c b/lib/sbi/sbi_emulate_csr.c
> > index dbb1755..aec9d3c 100644
> > --- a/lib/sbi/sbi_emulate_csr.c
> > +++ b/lib/sbi/sbi_emulate_csr.c
> > @@ -24,7 +24,7 @@ static bool hpm_allowed(int hpm_num, ulong prev_mode, bool virt)
> > struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> >
> > if (prev_mode <= PRV_S) {
> > - if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTEREN)) {
> > + if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10) {
> > cen &= csr_read(CSR_MCOUNTEREN);
> > if (virt)
> > cen &= csr_read(CSR_HCOUNTEREN);
> > @@ -33,7 +33,7 @@ static bool hpm_allowed(int hpm_num, ulong prev_mode, bool virt)
> > }
> > }
> > if (prev_mode == PRV_U) {
> > - if (sbi_hart_has_feature(scratch, SBI_HART_HAS_SCOUNTEREN))
> > + if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10)
> > cen &= csr_read(CSR_SCOUNTEREN);
> > else
> > cen = 0;
> > diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> > index ed4e631..ed8a061 100644
> > --- a/lib/sbi/sbi_hart.c
> > +++ b/lib/sbi/sbi_hart.c
> > @@ -58,7 +58,7 @@ static void mstatus_init(struct sbi_scratch *scratch)
> >
> > /* Disable user mode usage of all perf counters except default ones (CY, TM, IR) */
> > if (misa_extension('S') &&
> > - sbi_hart_has_feature(scratch, SBI_HART_HAS_SCOUNTEREN))
> > + sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10)
> > csr_write(CSR_SCOUNTEREN, 7);
> >
>
> mstatus_init invokes sbi_hart_priv_version 4 times. Keep the priv
> version in a local variable ?
>
> > /**
> > @@ -66,7 +66,7 @@ static void mstatus_init(struct sbi_scratch *scratch)
> > * Supervisor mode usage for all counters are enabled by default
> > * But counters will not run until mcountinhibit is set.
> > */
> > - if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTEREN))
> > + if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10)
> > csr_write(CSR_MCOUNTEREN, -1);
> >
> > /* All programmable counters will start running at runtime after S-mode request */
> > @@ -402,12 +402,6 @@ static inline char *sbi_hart_feature_id2string(unsigned long feature)
> > return NULL;
> >
> > switch (feature) {
> > - case SBI_HART_HAS_SCOUNTEREN:
> > - fstr = "scounteren";
> > - break;
> > - case SBI_HART_HAS_MCOUNTEREN:
> > - fstr = "mcounteren";
> > - break;
> > case SBI_HART_HAS_MCOUNTINHIBIT:
> > fstr = "mcountinhibit";
> > break;
> > @@ -614,23 +608,10 @@ __mhpm_skip:
> > #undef __check_csr_2
> > #undef __check_csr
> >
> > - /* Detect if hart supports SCOUNTEREN feature */
> > - val = csr_read_allowed(CSR_SCOUNTEREN, (unsigned long)&trap);
> > - if (!trap.cause) {
> > - hfeatures->priv_version = SBI_HART_PRIV_VER_1_10;
> > - csr_write_allowed(CSR_SCOUNTEREN, (unsigned long)&trap, val);
> > - if (!trap.cause)
> > - hfeatures->features |= SBI_HART_HAS_SCOUNTEREN;
> > - }
> > -
> > - /* Detect if hart supports MCOUNTEREN feature */
> > + /* Detect if hart supports Priv v1.10 */
> > val = csr_read_allowed(CSR_MCOUNTEREN, (unsigned long)&trap);
> > - if (!trap.cause) {
> > + if (!trap.cause)
> > hfeatures->priv_version = SBI_HART_PRIV_VER_1_10;
> > - csr_write_allowed(CSR_MCOUNTEREN, (unsigned long)&trap, val);
> > - if (!trap.cause)
> > - hfeatures->features |= SBI_HART_HAS_MCOUNTEREN;
> > - }
> >
> > /* Detect if hart supports MCOUNTINHIBIT feature */
> > val = csr_read_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap);
> > @@ -651,7 +632,7 @@ __mhpm_skip:
> >
> > /* Counter overflow/filtering is not useful without mcounter/inhibit */
> > if (hfeatures->features & SBI_HART_HAS_MCOUNTINHIBIT &&
> > - hfeatures->features & SBI_HART_HAS_MCOUNTEREN) {
> > + hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
>
> nit comment:
> this should be SBI_HART_PRIV_VER_1_10 in this patch.
> the check should be SBI_HART_PRIV_VER_1_12 when you remove
> mcountinhibit (PATCH 5)
>
> > /* 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 7ea0ca5..853229e 100644
> > --- a/lib/sbi/sbi_pmu.c
> > +++ b/lib/sbi/sbi_pmu.c
> > @@ -729,7 +729,8 @@ void sbi_pmu_exit(struct sbi_scratch *scratch)
> > if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
> > csr_write(CSR_MCOUNTINHIBIT, 0xFFFFFFF8);
> >
> > - csr_write(CSR_MCOUNTEREN, -1);
> > + if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10)
> > + csr_write(CSR_MCOUNTEREN, -1);
> > pmu_reset_event_map(hartid);
> > }
> >
> > --
> > 2.34.1
> >
>
> Other than that, LGTM.
>
> Reviewed-by: Atish Patra <atishp at rivosinc.com>
Applied this patch to the riscv/opensbi repo
Regards,
Anup
> --
> Regards,
> Atish
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