[PATCH 04/11] lib: sbi: Remove MCOUNTEREN and SCOUNTEREN hart features
Atish Patra
atishp at atishpatra.org
Tue May 3 18:51:22 PDT 2022
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>
--
Regards,
Atish
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