| Message ID | 20240229010130.1380926-4-atishp@rivosinc.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | RISC-V SBI v2.0 PMU improvements and Perf sampling in KVM guest | expand |
On Wed, Feb 28, 2024 at 05:01:18PM -0800, Atish Patra wrote: > SBI v2.0 introduced a explicit function to read the upper 32 bits > for any firmwar counter width that is longer than 32bits. firmware > This is only applicable for RV32 where firmware counter can be > 64 bit. > > Acked-by: Palmer Dabbelt <palmer@rivosinc.com> > Reviewed-by: Conor Dooley <conor.dooley@microchip.com> > Reviewed-by: Anup Patel <anup@brainfault.org> > Signed-off-by: Atish Patra <atishp@rivosinc.com> > --- > drivers/perf/riscv_pmu_sbi.c | 20 ++++++++++++++++---- > 1 file changed, 16 insertions(+), 4 deletions(-) > > diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c > index 16acd4dcdb96..ea0fdb589f0d 100644 > --- a/drivers/perf/riscv_pmu_sbi.c > +++ b/drivers/perf/riscv_pmu_sbi.c > @@ -35,6 +35,8 @@ > PMU_FORMAT_ATTR(event, "config:0-47"); > PMU_FORMAT_ATTR(firmware, "config:63"); > > +static bool sbi_v2_available; > + > static struct attribute *riscv_arch_formats_attr[] = { > &format_attr_event.attr, > &format_attr_firmware.attr, > @@ -488,16 +490,23 @@ static u64 pmu_sbi_ctr_read(struct perf_event *event) > struct hw_perf_event *hwc = &event->hw; > int idx = hwc->idx; > struct sbiret ret; > - union sbi_pmu_ctr_info info; > u64 val = 0; > + union sbi_pmu_ctr_info info = pmu_ctr_list[idx]; > > if (pmu_sbi_is_fw_event(event)) { > ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ, > hwc->idx, 0, 0, 0, 0, 0); > - if (!ret.error) > - val = ret.value; > + if (ret.error) > + return 0; > + > + val = ret.value; > + if (IS_ENABLED(CONFIG_32BIT) && sbi_v2_available && info.width >= 32) { > + ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ_HI, > + hwc->idx, 0, 0, 0, 0, 0); > + if (!ret.error) Getting an error here indicates a buggy SBI. Maybe we should have a warn-once? > + val |= ((u64)ret.value << 32); > + } > } else { > - info = pmu_ctr_list[idx]; > val = riscv_pmu_ctr_read_csr(info.csr); > if (IS_ENABLED(CONFIG_32BIT)) > val = ((u64)riscv_pmu_ctr_read_csr(info.csr + 0x80)) << 31 | val; > @@ -1108,6 +1117,9 @@ static int __init pmu_sbi_devinit(void) > return 0; > } > > + if (sbi_spec_version >= sbi_mk_version(2, 0)) > + sbi_v2_available = true; > + > ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_RISCV_STARTING, > "perf/riscv/pmu:starting", > pmu_sbi_starting_cpu, pmu_sbi_dying_cpu); > -- > 2.34.1 > Either way, Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c index 16acd4dcdb96..ea0fdb589f0d 100644 --- a/drivers/perf/riscv_pmu_sbi.c +++ b/drivers/perf/riscv_pmu_sbi.c @@ -35,6 +35,8 @@ PMU_FORMAT_ATTR(event, "config:0-47"); PMU_FORMAT_ATTR(firmware, "config:63"); +static bool sbi_v2_available; + static struct attribute *riscv_arch_formats_attr[] = { &format_attr_event.attr, &format_attr_firmware.attr, @@ -488,16 +490,23 @@ static u64 pmu_sbi_ctr_read(struct perf_event *event) struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; struct sbiret ret; - union sbi_pmu_ctr_info info; u64 val = 0; + union sbi_pmu_ctr_info info = pmu_ctr_list[idx]; if (pmu_sbi_is_fw_event(event)) { ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ, hwc->idx, 0, 0, 0, 0, 0); - if (!ret.error) - val = ret.value; + if (ret.error) + return 0; + + val = ret.value; + if (IS_ENABLED(CONFIG_32BIT) && sbi_v2_available && info.width >= 32) { + ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ_HI, + hwc->idx, 0, 0, 0, 0, 0); + if (!ret.error) + val |= ((u64)ret.value << 32); + } } else { - info = pmu_ctr_list[idx]; val = riscv_pmu_ctr_read_csr(info.csr); if (IS_ENABLED(CONFIG_32BIT)) val = ((u64)riscv_pmu_ctr_read_csr(info.csr + 0x80)) << 31 | val; @@ -1108,6 +1117,9 @@ static int __init pmu_sbi_devinit(void) return 0; } + if (sbi_spec_version >= sbi_mk_version(2, 0)) + sbi_v2_available = true; + ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_RISCV_STARTING, "perf/riscv/pmu:starting", pmu_sbi_starting_cpu, pmu_sbi_dying_cpu);