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arm64: perf: Add support caps under sysfs
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ARMv8.4-PMU introduces the PMMIR_EL1 registers and some new PMU events,
like STALL_SLOT etc, are related to it. Let's add a caps directory to
/sys/bus/event_source/devices/armv8_pmuv3_0/ and support slots from
PMMIR_EL1 registers in this entry. The user programs can get the slots
from sysfs directly.

/sys/bus/event_source/devices/armv8_pmuv3_0/caps/slots is exposed
under sysfs. Both ARMv8.4-PMU and STALL_SLOT event are implemented,
it returns the slots from PMMIR_EL1, otherwise it will return 0.

Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/1600754025-53535-1-git-send-email-zhangshaokun@hisilicon.com
Signed-off-by: Will Deacon <will@kernel.org>
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Shaokun Zhang authored and Will Deacon committed Sep 28, 2020
1 parent 688494a commit f5be3a6
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Showing 4 changed files with 78 additions and 33 deletions.
3 changes: 3 additions & 0 deletions arch/arm64/include/asm/perf_event.h
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Original file line number Diff line number Diff line change
Expand Up @@ -236,6 +236,9 @@
#define ARMV8_PMU_USERENR_CR (1 << 2) /* Cycle counter can be read at EL0 */
#define ARMV8_PMU_USERENR_ER (1 << 3) /* Event counter can be read at EL0 */

/* PMMIR_EL1.SLOTS mask */
#define ARMV8_PMU_SLOTS_MASK 0xff

#ifdef CONFIG_PERF_EVENTS
struct pt_regs;
extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
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2 changes: 2 additions & 0 deletions arch/arm64/include/asm/sysreg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -321,6 +321,8 @@
#define SYS_PMINTENSET_EL1 sys_reg(3, 0, 9, 14, 1)
#define SYS_PMINTENCLR_EL1 sys_reg(3, 0, 9, 14, 2)

#define SYS_PMMIR_EL1 sys_reg(3, 0, 9, 14, 6)

#define SYS_MAIR_EL1 sys_reg(3, 0, 10, 2, 0)
#define SYS_AMAIR_EL1 sys_reg(3, 0, 10, 3, 0)

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103 changes: 70 additions & 33 deletions arch/arm64/kernel/perf_event.c
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Original file line number Diff line number Diff line change
Expand Up @@ -305,6 +305,28 @@ static struct attribute_group armv8_pmuv3_format_attr_group = {
.attrs = armv8_pmuv3_format_attrs,
};

static ssize_t slots_show(struct device *dev, struct device_attribute *attr,
char *page)
{
struct pmu *pmu = dev_get_drvdata(dev);
struct arm_pmu *cpu_pmu = container_of(pmu, struct arm_pmu, pmu);
u32 slots = cpu_pmu->reg_pmmir & ARMV8_PMU_SLOTS_MASK;

return snprintf(page, PAGE_SIZE, "0x%08x\n", slots);
}

static DEVICE_ATTR_RO(slots);

static struct attribute *armv8_pmuv3_caps_attrs[] = {
&dev_attr_slots.attr,
NULL,
};

static struct attribute_group armv8_pmuv3_caps_attr_group = {
.name = "caps",
.attrs = armv8_pmuv3_caps_attrs,
};

/*
* Perf Events' indices
*/
Expand Down Expand Up @@ -984,6 +1006,12 @@ static void __armv8pmu_probe_pmu(void *info)

bitmap_from_arr32(cpu_pmu->pmceid_ext_bitmap,
pmceid, ARMV8_PMUV3_MAX_COMMON_EVENTS);

/* store PMMIR_EL1 register for sysfs */
if (pmuver >= ID_AA64DFR0_PMUVER_8_4 && (pmceid_raw[1] & BIT(31)))
cpu_pmu->reg_pmmir = read_cpuid(PMMIR_EL1);
else
cpu_pmu->reg_pmmir = 0;
}

static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu)
Expand All @@ -1006,7 +1034,8 @@ static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu)
static int armv8_pmu_init(struct arm_pmu *cpu_pmu, char *name,
int (*map_event)(struct perf_event *event),
const struct attribute_group *events,
const struct attribute_group *format)
const struct attribute_group *format,
const struct attribute_group *caps)
{
int ret = armv8pmu_probe_pmu(cpu_pmu);
if (ret)
Expand All @@ -1031,104 +1060,112 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu, char *name,
events : &armv8_pmuv3_events_attr_group;
cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_FORMATS] = format ?
format : &armv8_pmuv3_format_attr_group;
cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_CAPS] = caps ?
caps : &armv8_pmuv3_caps_attr_group;

return 0;
}

static int armv8_pmu_init_nogroups(struct arm_pmu *cpu_pmu, char *name,
int (*map_event)(struct perf_event *event))
{
return armv8_pmu_init(cpu_pmu, name, map_event, NULL, NULL, NULL);
}

static int armv8_pmuv3_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_pmuv3",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_pmuv3",
armv8_pmuv3_map_event);
}

static int armv8_a34_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a34",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a34",
armv8_pmuv3_map_event);
}

static int armv8_a35_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a35",
armv8_a53_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a35",
armv8_a53_map_event);
}

static int armv8_a53_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a53",
armv8_a53_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a53",
armv8_a53_map_event);
}

static int armv8_a55_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a55",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a55",
armv8_pmuv3_map_event);
}

static int armv8_a57_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a57",
armv8_a57_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a57",
armv8_a57_map_event);
}

static int armv8_a65_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a65",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a65",
armv8_pmuv3_map_event);
}

static int armv8_a72_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a72",
armv8_a57_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a72",
armv8_a57_map_event);
}

static int armv8_a73_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a73",
armv8_a73_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a73",
armv8_a73_map_event);
}

static int armv8_a75_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a75",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a75",
armv8_pmuv3_map_event);
}

static int armv8_a76_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a76",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a76",
armv8_pmuv3_map_event);
}

static int armv8_a77_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cortex_a77",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cortex_a77",
armv8_pmuv3_map_event);
}

static int armv8_e1_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_neoverse_e1",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_neoverse_e1",
armv8_pmuv3_map_event);
}

static int armv8_n1_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_neoverse_n1",
armv8_pmuv3_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_neoverse_n1",
armv8_pmuv3_map_event);
}

static int armv8_thunder_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_cavium_thunder",
armv8_thunder_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_cavium_thunder",
armv8_thunder_map_event);
}

static int armv8_vulcan_pmu_init(struct arm_pmu *cpu_pmu)
{
return armv8_pmu_init(cpu_pmu, "armv8_brcm_vulcan",
armv8_vulcan_map_event, NULL, NULL);
return armv8_pmu_init_nogroups(cpu_pmu, "armv8_brcm_vulcan",
armv8_vulcan_map_event);
}

static const struct of_device_id armv8_pmu_of_device_ids[] = {
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3 changes: 3 additions & 0 deletions include/linux/perf/arm_pmu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,7 @@ enum armpmu_attr_groups {
ARMPMU_ATTR_GROUP_COMMON,
ARMPMU_ATTR_GROUP_EVENTS,
ARMPMU_ATTR_GROUP_FORMATS,
ARMPMU_ATTR_GROUP_CAPS,
ARMPMU_NR_ATTR_GROUPS
};

Expand Down Expand Up @@ -109,6 +110,8 @@ struct arm_pmu {
struct notifier_block cpu_pm_nb;
/* the attr_groups array must be NULL-terminated */
const struct attribute_group *attr_groups[ARMPMU_NR_ATTR_GROUPS + 1];
/* store the PMMIR_EL1 to expose slots */
u64 reg_pmmir;

/* Only to be used by ACPI probing code */
unsigned long acpi_cpuid;
Expand Down

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