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* [PATCH v6] arm64: perf: Add support caps in sysfs
@ 2020-07-23 11:56 Shaokun Zhang
  2020-09-07 10:30 ` Will Deacon
  0 siblings, 1 reply; 3+ messages in thread
From: Shaokun Zhang @ 2020-07-23 11:56 UTC (permalink / raw)
  To: linux-arm-kernel; +Cc: Shaokun Zhang, Mark Rutland, Will Deacon

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
through sysfs. Both ARMv8.4-PMU and STALL_SLOT event are implemented,
it returns the slots from PMMIR_EL1, otherwise it will return an empty
string.

Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
---
ChangeLog in v6:
    * Fix heterogeneous CPUs issue.

ChangeLog in v5:
    * Add check STALL_SLOT in PMCEID1_EL0

ChangeLog in v4:
    * Address Will's comments.

ChangeLog in v3:
    * Fix one typo in patch3

ChangeLog in v2:
    * Add caps entry in sysfs
    * Fix the PMU events typos
    * Add one new patch to correct event ID in sysfs

 arch/arm64/include/asm/perf_event.h |   3 +
 arch/arm64/include/asm/sysreg.h     |   2 +
 arch/arm64/kernel/perf_event.c      | 106 +++++++++++++++++++++++++-----------
 include/linux/perf/arm_pmu.h        |   3 +
 4 files changed, 81 insertions(+), 33 deletions(-)

diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
index 2c2d7dbe8a02..60731f602d3e 100644
--- a/arch/arm64/include/asm/perf_event.h
+++ b/arch/arm64/include/asm/perf_event.h
@@ -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);
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 463175f80341..56c45a9207c7 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -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)
 
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 462f9a9cc44b..1078f23ebe11 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -302,6 +302,31 @@ 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);
+	int slots = cpu_pmu->reg_pmmir & ARMV8_PMU_SLOTS_MASK;
+
+	if (slots)
+		return snprintf(page, PAGE_SIZE, "0x%02x\n", slots);
+	else
+		return 0;
+}
+
+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
  */
@@ -997,6 +1022,12 @@ 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)
@@ -1019,7 +1050,8 @@ 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)
@@ -1044,104 +1076,112 @@ 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[] = {
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 5b616dde9a4c..505480217cf1 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -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
 };
 
@@ -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;
-- 
2.7.4


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^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH v6] arm64: perf: Add support caps in sysfs
  2020-07-23 11:56 [PATCH v6] arm64: perf: Add support caps in sysfs Shaokun Zhang
@ 2020-09-07 10:30 ` Will Deacon
  2020-09-08  7:28   ` Shaokun Zhang
  0 siblings, 1 reply; 3+ messages in thread
From: Will Deacon @ 2020-09-07 10:30 UTC (permalink / raw)
  To: Shaokun Zhang; +Cc: Mark Rutland, linux-arm-kernel

On Thu, Jul 23, 2020 at 07:56:52PM +0800, Shaokun Zhang wrote:
> 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
> through sysfs. Both ARMv8.4-PMU and STALL_SLOT event are implemented,
> it returns the slots from PMMIR_EL1, otherwise it will return an empty
> string.

Returning an empty string seems a little hostile for parsing code here.
Wouldn't we be better off either returning 0 or not exposing the file at
all in the case that the feature is not supported?

Will

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^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH v6] arm64: perf: Add support caps in sysfs
  2020-09-07 10:30 ` Will Deacon
@ 2020-09-08  7:28   ` Shaokun Zhang
  0 siblings, 0 replies; 3+ messages in thread
From: Shaokun Zhang @ 2020-09-08  7:28 UTC (permalink / raw)
  To: Will Deacon; +Cc: Mark Rutland, linux-arm-kernel

Hi Will,

在 2020/9/7 18:30, Will Deacon 写道:
> On Thu, Jul 23, 2020 at 07:56:52PM +0800, Shaokun Zhang wrote:
>> 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
>> through sysfs. Both ARMv8.4-PMU and STALL_SLOT event are implemented,
>> it returns the slots from PMMIR_EL1, otherwise it will return an empty
>> string.
> 
> Returning an empty string seems a little hostile for parsing code here.
> Wouldn't we be better off either returning 0 or not exposing the file at

Since you have given comments[1] to get ride of armv8pmu_caps_attr_is_visible,
I will return 0 when cpu_pmu->reg_pmmir stores the ZERO.

+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);
+       int slots = cpu_pmu->reg_pmmir & ARMV8_PMU_SLOTS_MASK;
+
+       return snprintf(page, PAGE_SIZE, "0x%02x\n", slots);
+}

If you are ok, I will fix it in next version.

[1] https://www.spinics.net/lists/arm-kernel/msg824289.html

Thanks,
Shaokun


> all in the case that the feature is not supported?
> 
> Will
> 
> .
> 


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^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-09-08  7:29 UTC | newest]

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