arm64: perf: Add more support on caps under sysfs

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>
Link: https://lore.kernel.org/r/1622704502-63951-1-git-send-email-zhangshaokun@hisilicon.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
index 60731f6..4ef6f19 100644 (file)
--- 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 44b6eda..a661010 100644 (file)
--- 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,
 };