* [PATCH v3] arm64: perf: Add more support on caps under sysfs
@ 2021-06-03 7:15 Shaokun Zhang
2021-06-03 18:14 ` Will Deacon
0 siblings, 1 reply; 2+ messages in thread
From: Shaokun Zhang @ 2021-06-03 7:15 UTC (permalink / raw)
To: linux-arm-kernel; +Cc: Shaokun Zhang, Will Deacon, Mark Rutland, Robin Murphy
Armv8.7 has introduced BUS_SLOTS and BUS_WIDTH in PMMIR_EL1 register,
add two entries in caps for bus_slots and bus_width under sysfs. It
will return the true slots and width if the information is available,
otherwise it will return 0.
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
---
ChangeLog:
v2-->v3:
1. Address Will' comment on snprintf and local variable
v1-->v2:
1. Address Robin's comment on bus_width calculation.
2. Add the comment on calculation formula.
arch/arm64/include/asm/perf_event.h | 5 +++++
arch/arm64/kernel/perf_event.c | 33 +++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+)
diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
index 60731f602d3e..4ef6f19331f9 100644
--- a/arch/arm64/include/asm/perf_event.h
+++ b/arch/arm64/include/asm/perf_event.h
@@ -239,6 +239,11 @@
/* PMMIR_EL1.SLOTS mask */
#define ARMV8_PMU_SLOTS_MASK 0xff
+#define ARMV8_PMU_BUS_SLOTS_SHIFT 8
+#define ARMV8_PMU_BUS_SLOTS_MASK 0xff
+#define ARMV8_PMU_BUS_WIDTH_SHIFT 16
+#define ARMV8_PMU_BUS_WIDTH_MASK 0xf
+
#ifdef CONFIG_PERF_EVENTS
struct pt_regs;
extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index f594957e29bd..db3d748061f1 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -317,8 +317,41 @@ static ssize_t slots_show(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_RO(slots);
+static ssize_t bus_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 bus_slots = (cpu_pmu->reg_pmmir >> ARMV8_PMU_BUS_SLOTS_SHIFT)
+ & ARMV8_PMU_BUS_SLOTS_MASK;
+
+ return sysfs_emit(page, "0x%08x\n", bus_slots);
+}
+
+static DEVICE_ATTR_RO(bus_slots);
+
+static ssize_t bus_width_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 bus_width = (cpu_pmu->reg_pmmir >> ARMV8_PMU_BUS_WIDTH_SHIFT)
+ & ARMV8_PMU_BUS_WIDTH_MASK;
+ u32 val = 0;
+
+ /* Encoded as Log2(number of bytes), plus one */
+ if (bus_width > 2 && bus_width < 13)
+ val = 1 << (bus_width - 1);
+
+ return sysfs_emit(page, "0x%08x\n", val);
+}
+
+static DEVICE_ATTR_RO(bus_width);
+
static struct attribute *armv8_pmuv3_caps_attrs[] = {
&dev_attr_slots.attr,
+ &dev_attr_bus_slots.attr,
+ &dev_attr_bus_width.attr,
NULL,
};
--
2.7.4
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v3] arm64: perf: Add more support on caps under sysfs
2021-06-03 7:15 [PATCH v3] arm64: perf: Add more support on caps under sysfs Shaokun Zhang
@ 2021-06-03 18:14 ` Will Deacon
0 siblings, 0 replies; 2+ messages in thread
From: Will Deacon @ 2021-06-03 18:14 UTC (permalink / raw)
To: linux-arm-kernel, Shaokun Zhang
Cc: catalin.marinas, kernel-team, Will Deacon, Mark Rutland, Robin Murphy
On Thu, 3 Jun 2021 15:15:02 +0800, Shaokun Zhang wrote:
> Armv8.7 has introduced BUS_SLOTS and BUS_WIDTH in PMMIR_EL1 register,
> add two entries in caps for bus_slots and bus_width under sysfs. It
> will return the true slots and width if the information is available,
> otherwise it will return 0.
Applied to will (for-next/perf), thanks!
[1/1] arm64: perf: Add more support on caps under sysfs
https://git.kernel.org/will/c/281e44f5fd4f
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2021-06-03 18:16 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-03 7:15 [PATCH v3] arm64: perf: Add more support on caps under sysfs Shaokun Zhang
2021-06-03 18:14 ` Will Deacon
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).