Messages in this thread | | | From | Atish Patra <> | Date | Mon, 20 Jun 2022 12:40:20 -0700 | Subject | Re: [PATCH v4 1/1] RISC-V: Create unique identification for SoC PMU |
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On Mon, Jun 20, 2022 at 7:40 AM Nikita Shubin <nikita.shubin@maquefel.me> wrote: > > On Mon, 20 Jun 2022 17:30:58 +0530 > Anup Patel <apatel@ventanamicro.com> wrote: > > > On Sun, Jun 19, 2022 at 4:41 PM Nikita Shubin > > <nikita.shubin@maquefel.me> wrote: > > > > > > From: Nikita Shubin <n.shubin@yadro.com> > > > > > > Provide RISC-V SBI PMU id to distinguish different cores or SoCs via > > > "devices/platform/riscv-pmu/id" sysfs entry. > > > > > > The identification is generated as string of marchid, mimpid, > > > mvendorid in hex format separated by coma - "0x70032,0x70032,0x0". > > > > > > The CSRs are detailed in the RISC-V privileged spec [1]. > > > [1] https://github.com/riscv/riscv-isa-manual > > > > > > Inspired-by: João Mário Domingos <joao.mario@tecnico.ulisboa.pt> > > > Signed-off-by: Nikita Shubin <n.shubin@yadro.com> > > > > The mvendorid, marchid, and mimpid can be useful to apps other than > > perf tool. > > > > I have tried to extend /proc/cpuinfo with this information which can > > be parsed by perf tool: > > https://lore.kernel.org/all/20220620115549.1529597-1-apatel@ventanamicro.com/ > > Atish, what do you think about this ? > > RISC-V perf can rely on "/proc/cpuinfo", in some similar manner like > "tools/perf/arch/s390/util/header.c" does. >
Yes. We can expose these three values either in sysfs or procfs (/proc/cpuinfo). For perf tool, it shouldn't matter as the header.c will need to generate the unique cpuid string from either.
I am not sure if any other userspace tool prefers to parse sysfs instead of cpuinfo.
> Can it create problems with pmu identification in case of hetergenous > harts ? >
Does perf support hetergenous harts at all ? ARM64 code (tool/perf/arch/arm64/util/header.c) just breaks out of the loop after finding the first MIDR.
> > > > Regards, > > Anup > > > > > --- > > > v3->v4: > > > - use string for pmuid > > > - rename pmu_sbi_id_show to id_show > > > - fix error print message in id_show > > > - fix DEVICE_ATTR to use octal permissions > > > --- > > > arch/riscv/kernel/sbi.c | 3 +++ > > > drivers/perf/riscv_pmu_sbi.c | 41 > > > ++++++++++++++++++++++++++++++++++ include/linux/perf/riscv_pmu.h | > > > 1 + 3 files changed, 45 insertions(+) > > > > > > diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c > > > index 775d3322b422..50dd9b6ecc9e 100644 > > > --- a/arch/riscv/kernel/sbi.c > > > +++ b/arch/riscv/kernel/sbi.c > > > @@ -627,16 +627,19 @@ long sbi_get_mvendorid(void) > > > { > > > return __sbi_base_ecall(SBI_EXT_BASE_GET_MVENDORID); > > > } > > > +EXPORT_SYMBOL(sbi_get_mvendorid); > > > > > > long sbi_get_marchid(void) > > > { > > > return __sbi_base_ecall(SBI_EXT_BASE_GET_MARCHID); > > > } > > > +EXPORT_SYMBOL(sbi_get_marchid); > > > > > > long sbi_get_mimpid(void) > > > { > > > return __sbi_base_ecall(SBI_EXT_BASE_GET_MIMPID); > > > } > > > +EXPORT_SYMBOL(sbi_get_mimpid); > > > > > > static void sbi_send_cpumask_ipi(const struct cpumask *target) > > > { > > > diff --git a/drivers/perf/riscv_pmu_sbi.c > > > b/drivers/perf/riscv_pmu_sbi.c index dca3537a8dcc..be812f855617 > > > 100644 --- a/drivers/perf/riscv_pmu_sbi.c > > > +++ b/drivers/perf/riscv_pmu_sbi.c > > > @@ -693,6 +693,28 @@ static int pmu_sbi_setup_irqs(struct riscv_pmu > > > *pmu, struct platform_device *pde return 0; > > > } > > > > > > +static ssize_t id_show(struct device *dev, > > > + struct device_attribute *attr, char > > > *buf) +{ > > > + int len; > > > + struct riscv_pmu *pmu = container_of(dev_get_drvdata(dev), > > > struct riscv_pmu, pmu); + > > > + len = sprintf(buf, "%s\n", pmu->pmuid); > > > + if (len <= 0) > > > + dev_err(dev, "invalid sprintf len: %d\n", len); > > > + > > > + return len; > > > +} > > > + > > > +static DEVICE_ATTR(id, 0644, id_show, NULL); > > > + > > > +static struct attribute *pmu_sbi_attrs[] = { > > > + &dev_attr_id.attr, > > > + NULL > > > +}; > > > + > > > +ATTRIBUTE_GROUPS(pmu_sbi); > > > + > > > static int pmu_sbi_device_probe(struct platform_device *pdev) > > > { > > > struct riscv_pmu *pmu = NULL; > > > @@ -714,6 +736,14 @@ static int pmu_sbi_device_probe(struct > > > platform_device *pdev) if (pmu_sbi_get_ctrinfo(num_counters)) > > > goto out_free; > > > > > > + /* fill pmuid */ > > > + pmu->pmuid = kasprintf(GFP_KERNEL, "0x%lx,0x%lx,0x%lx", > > > + sbi_get_marchid(), > > > + sbi_get_mimpid(), > > > + sbi_get_mvendorid()); > > > + if (!pmu->pmuid) > > > + goto out_free_pmuid; > > > + > > > ret = pmu_sbi_setup_irqs(pmu, pdev); > > > if (ret < 0) { > > > pr_info("Perf sampling/filtering is not supported > > > as sscof extension is not available\n"); @@ -739,8 +769,19 @@ > > > static int pmu_sbi_device_probe(struct platform_device *pdev) > > > return ret; } > > > > > > + ret = sysfs_create_group(&pdev->dev.kobj, &pmu_sbi_group); > > > + if (ret) { > > > + dev_err(&pdev->dev, "sysfs creation failed\n"); > > > + return ret; > > > + } > > > + > > > + pdev->dev.groups = pmu_sbi_groups; > > > + dev_set_drvdata(&pdev->dev, pmu); > > > + > > > return 0; > > > > > > +out_free_pmuid: > > > + kfree(pmu->pmuid); > > > out_free: > > > kfree(pmu); > > > return ret; > > > diff --git a/include/linux/perf/riscv_pmu.h > > > b/include/linux/perf/riscv_pmu.h index 46f9b6fe306e..cf3557b77fb8 > > > 100644 --- a/include/linux/perf/riscv_pmu.h > > > +++ b/include/linux/perf/riscv_pmu.h > > > @@ -42,6 +42,7 @@ struct cpu_hw_events { > > > struct riscv_pmu { > > > struct pmu pmu; > > > char *name; > > > + char *pmuid; > > > > > > irqreturn_t (*handle_irq)(int irq_num, void *dev); > > > > > > -- > > > 2.35.1 > > > >
-- Regards, Atish
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