There are many ways that support for the new CXL hotness monitoring unit
could be enabled.
The existing infrastructure of perf + auxiliary buffers is used for the
similar activity of trace capture.
This driver is based on the existing hisi_ptt (PCI trace and tune) driver
and the CXL PMU driver. Testing was done against QEMU emulation of
the feature but it's early days and lots more testing is needed as
this is a flexible specification with many corner cases.
The raw hotlist elements cannot be interpreted without knowing
the counter width. This is unfortunately dependent in an implementation
defined way on the unit size used for monitoring.
As such, store this and a count of new hotlist entrees in a header
that is inserted at the start of each set of records added to the auxiliary
buffer.
TODO: Add capabilities to expose what can be set for at least some
of these parameters.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
drivers/cxl/Kconfig | 6 +
drivers/cxl/Makefile | 3 +
drivers/cxl/core/core.h | 1 +
drivers/cxl/core/port.c | 2 +
drivers/cxl/cxl.h | 1 +
drivers/cxl/hmu.c | 880 ++++++++++++++++++++++++++++++++++++++++
6 files changed, 893 insertions(+)
diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 876469e23f7a..c420f828fe20 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -146,4 +146,10 @@ config CXL_REGION_INVALIDATION_TEST
If unsure, or if this kernel is meant for production environments,
say N.
+config CXL_HMU
+ tristate "CXL: Hotness Monitoring Unit Driver"
+ depends on PERF_EVENTS
+ help
+ Read data out from the CXL hotness units and provide it to userspace
+ via the perf auxbuffer framework.
endif
diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile
index 2caa90fa4bf2..b678aa927298 100644
--- a/drivers/cxl/Makefile
+++ b/drivers/cxl/Makefile
@@ -7,15 +7,18 @@
# - 'mem' and 'pmem' before endpoint drivers so that memdevs are
# immediately enabled
# - 'pci' last, also mirrors the hardware enumeration hierarchy
+# - 'hmu' doesn't matter for now.
obj-y += core/
obj-$(CONFIG_CXL_PORT) += cxl_port.o
obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
obj-$(CONFIG_CXL_MEM) += cxl_mem.o
obj-$(CONFIG_CXL_PCI) += cxl_pci.o
+obj-$(CONFIG_CXL_HMU) += cxl_hmu.o
cxl_port-y := port.o
cxl_acpi-y := acpi.o
cxl_pmem-y := pmem.o security.o
cxl_mem-y := mem.o
cxl_pci-y := pci.o
+cxl_hmu-y := hmu.o
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 0c62b4069ba0..88c673a4d950 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -6,6 +6,7 @@
extern const struct device_type cxl_nvdimm_bridge_type;
extern const struct device_type cxl_nvdimm_type;
+extern const struct device_type cxl_hmu_type;
extern const struct device_type cxl_pmu_type;
extern struct attribute_group cxl_base_attribute_group;
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index af92c67bc954..a91712757830 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -74,6 +74,8 @@ static int cxl_device_id(const struct device *dev)
return CXL_DEVICE_REGION;
if (dev->type == &cxl_pmu_type)
return CXL_DEVICE_PMU;
+ if (dev->type == &cxl_hmu_type)
+ return CXL_DEVICE_HMU;
return 0;
}
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 8172bc1f7a8d..bd190e2baa1d 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -850,6 +850,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv);
#define CXL_DEVICE_PMEM_REGION 7
#define CXL_DEVICE_DAX_REGION 8
#define CXL_DEVICE_PMU 9
+#define CXL_DEVICE_HMU 10
#define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
#define CXL_MODALIAS_FMT "cxl:t%d"
diff --git a/drivers/cxl/hmu.c b/drivers/cxl/hmu.c
new file mode 100644
index 000000000000..9f5947afbb4b
--- /dev/null
+++ b/drivers/cxl/hmu.c
@@ -0,0 +1,880 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for CXL Hotness Monitoring unit
+ *
+ * Based on hisi_ptt.c (Author Yicong Yang <yangyicong@xxxxxxxxxxxxx>)
+ * Copyright (c) 2022-2024 HiSilicon Technologies Co., Ltd.
+ *
+ * TODO:
+ * - Add capabilities attributes to help userspace know what can be set.
+ * - Find out if timeouts are appropriate for real hardware. Currently
+ * assuming 0.1 seconds is enough for anything.
+ */
+#include <linux/dev_printk.h>
+#include <linux/perf_event.h>
+#include <linux/bitfield.h>
+#include <linux/spinlock.h>
+#include <linux/cleanup.h>
+#include <linux/vmalloc.h>
+#include <linux/device.h>
+#include <linux/iopoll.h>
+#include <linux/delay.h>
+#include <linux/list.h>
+#include <linux/math.h>
+#include <linux/pci.h>
+
+#include "cxlpci.h"
+#include "cxl.h"
+#include "hmu.h"
+
+#define CHMU_COMMON_CAP0_REG 0x00
+#define CHMU_COMMON_CAP0_VER_MSK GENMASK(3, 0)
+#define CHMU_COMMON_CAP0_NUMINST_MSK GENMASK(15, 8)
+#define CHMU_COMMON_CAP1_REG 0x08
+#define CHMU_COMMON_CAP1_INSTLEN_MSK GENMASK(15, 0)
+
+/* Register offsets within instance */
+#define CHMU_INST0_CAP0_REG 0x00
+#define CHMU_INST0_CAP0_MSI_N_MSK GENMASK(3, 0)
+#define CHMU_INST0_CAP0_OVRFLW_CAP BIT(4)
+#define CHMU_INST0_CAP0_FILLTHRESH_CAP BIT(5)
+#define CHMU_INST0_CAP0_EPOCH_TYPE_MSK GENMASK(7, 6)
+#define CHMU_INST0_CAP0_EPOCH_TYPE_GLOBAL 0
+#define CHMU_INST0_CAP0_EPOCH_TYPE_PERCNT 1
+#define CHMU_INST0_CAP0_TRACK_NONTEE_R BIT(8)
+#define CHMU_INST0_CAP0_TRACK_NONTEE_W BIT(9)
+#define CHMU_INST0_CAP0_TRACK_NONTEE_RW BIT(10)
+#define CHMU_INST0_CAP0_TRACK_R BIT(11)
+#define CHMU_INST0_CAP0_TRACK_W BIT(12)
+#define CHMU_INST0_CAP0_TRACK_RW BIT(13)
+/* Epoch defined as scale * multiplier */
+#define CHMU_INST0_CAP0_EPOCH_MAX_SCALE_MSK GENMASK(19, 16)
+#define CHMU_EPOCH_SCALE_100US 1
+#define CHMU_EPOCH_SCALE_1MS 2
+#define CHMU_INST0_SCALE_10MS 3
+#define CHMU_INST0_SCALE_100MS 4
+#define CHMU_INST0_SCALE_1US 5
+#define CHMU_INST0_CAP0_EPOCH_MAX_MULT_MSK GENMASK(31, 20)
+#define CHMU_INST0_CAP0_EPOCH_MIN_SCALE_MSK GENMASK_ULL(35, 32)
+#define CHMU_INST0_CAP0_EPOCH_MIN_MULT_MSK GENMASK_ULL(47, 36)
+#define CHMU_INST0_CAP0_HOTLIST_SIZE_MSK GENMASK_ULL(63, 48)
+#define CHMU_INST0_CAP1_REG 0x08
+/* Power of 2 * 256 bits */
+#define CHMU_INST0_CAP1_UNIT_SIZE_MSK GENMASK(31, 0)
+/* Power of 2 */
+#define CHMU_INST0_CAP1_DOWNSAMP_MSK GENMASK_ULL(47, 32)
+#define CHMU_INST0_CAP1_EPOCH_SUP BIT_ULL(48)
+#define CHMU_INST0_CAP1_ALWAYS_ON_SUP BIT_ULL(49)
+#define CHMU_INST0_CAP1_RAND_DOWNSAMP_SUP BIT_ULL(50)
+#define CHMU_INST0_CAP1_ADDR_OVERLAP_SUP BIT_ULL(51)
+#define CHMU_INST0_CAP1_POSTPONED_ON_OVRFLOW_SUP BIT_ULL(52)
+
+/*
+ * In CXL r3.2 all defined as part of single giant CAP register.
+ * Where a whole 64 bits is in one field just name after the field.
+ */
+#define CHMU_INST0_RANGE_BITMAP_OFFSET_REG 0x10
+#define CHMU_INST0_HOTLIST_OFFSET_REG 0x18
+
+#define CHMU_INST0_CFG0_REG 0x40
+#define CHMU_INST0_CFG0_WHAT_MSK GENMASK(7, 0)
+#define CHMU_INST0_CFG0_WHAT_NONTEE_R 1
+#define CHMU_INST0_CFG0_WHAT_NONTEE_W 2
+#define CHMU_INST0_CFG0_WHAT_NONTEE_RW 3
+#define CHMU_INST0_CFG0_WHAT_R 4
+#define CHMU_INST0_CFG0_WHAT_W 5
+#define CHMU_INST0_CFG0_WHAT_RW 6
+#define CHMU_INST0_CFG0_RAND_DOWNSAMP_EN BIT(8)
+#define CHMU_INST0_CFG0_OVRFLW_INT_EN BIT(9)
+#define CHMU_INST0_CFG0_FILLTHRESH_INT_EN BIT(10)
+#define CHMU_INST0_CFG0_ENABLE BIT(16)
+#define CHMU_INST0_CFG0_RESET_COUNTERS BIT(17)
+#define CHMU_INST0_CFG0_HOTNESS_THRESH_MSK GENMASK_ULL(63, 32)
+#define CHMU_INST0_CFG1_REG 0x48
+#define CHMU_INST0_CFG1_UNIT_SIZE_MSK GENMASK(31, 0)
+#define CHMU_INST0_CFG1_DS_FACTOR_MSK GENMASK(35, 32)
+#define CHMU_INST0_CFG1_MODE_MSK GENMASK_ULL(47, 40)
+#define CHMU_INST0_CFG1_EPOCH_SCALE_MSK GENMASK_ULL(51, 48)
+#define CHMU_INST0_CFG1_EPOCH_MULT_MSK GENMASK_ULL(63, 52)
+#define CHMU_INST0_CFG2_REG 0x50
+#define CHMU_INST0_CFG2_FILLTHRESH_THRESHOLD_MSK GENMASK(15, 0)
+
+#define CHMU_INST0_STATUS_REG 0x60
+#define CHMU_INST0_STATUS_ENABLED BIT(0)
+#define CHMU_INST0_STATUS_OP_INPROG_MSK GENMASK(31, 16)
+#define CHMU_INST0_STATUS_OP_INPROG_NONE 0
+#define CHMU_INST0_STATUS_OP_INPROG_ENABLE 1
+#define CHMU_INST0_STATUS_OP_INPROG_DISABLE 2
+#define CHMU_INST0_STATUS_OP_INPROG_RESET 3
+#define CHMU_INST0_STATUS_COUNTER_WIDTH_MSK GENMASK_ULL(39, 32)
+#define CHMU_INST0_STATUS_OVRFLW BIT_ULL(40)
+#define CHMU_INST0_STATUS_FILLTHRESH BIT_ULL(41)
+
+/* 2 byte registers */
+#define CHMU_INST0_HEAD_REG 0x68
+#define CHMU_INST0_TAIL_REG 0x6A
+
+/* CFG attribute bit mappings */
+#define CXL_HMU_ATTR_CONFIG_EPOCH_TYPE_MASK GENMASK(1, 0)
+#define CXL_HMU_ATTR_CONFIG_ACCESS_TYPE_MASK GENMASK(9, 2)
+#define CXL_HMU_ATTR_CONFIG_EPOCH_SCALE_MASK GENMASK(13, 10)
+#define CXL_HMU_ATTR_CONFIG_EPOCH_MULT_MASK GENMASK(25, 14)
+#define CXL_HMU_ATTR_CONFIG_RANDOM_DS_MASK BIT(26)
+#define CXL_HMU_ATTR_CONFIG_DS_FACTOR_MASK GENMASK_ULL(34, 27)
+
+#define CXL_HMU_ATTR_CONFIG1_HOTNESS_THRESH_MASK GENMASK(31, 0)
+#define CXL_HMU_ATTR_CONFIG1_HOTNESS_GRANUAL_MASK GENMASK_ULL(63, 32)
+
+/* In multiples of 256MiB */
+#define CXL_HMU_ATTR_CONFIG2_DPA_BASE_MASK GENMASK(31, 0)
+#define CXL_HMU_ATTR_CONFIG2_DPA_SIZE_MASK GENMASK_ULL(63, 32)
+
+/* Range bitmap registers at offset 0x10 + Range Config Bitmap offset */
+/* Hotlist registers at offset 0x10 + Hotlist Register offset */
+static int cxl_hmu_cpuhp_state_num;
+
+enum cxl_hmu_reporting_mode {
+ CHMU_MODE_EPOCH = 0,
+ CHMU_MODE_ALWAYS_ON = 1,
+};
+
+struct cxl_hmu_info {
+ struct pmu pmu;
+ struct perf_output_handle handle;
+ void __iomem *base;
+ struct hlist_node node;
+ int irq;
+ int on_cpu;
+ u32 hot_thresh;
+ u32 hot_gran; /* power of 2, 256 to 2 GiB */
+ /* For now use a range rather than a bitmap, chunks of 256MiB */
+ u32 range_base;
+ u32 range_num;
+ enum cxl_hmu_reporting_mode reporting_mode;
+ u8 m2s_requests_to_track;
+ u8 ds_factor_pow2;
+ u8 epoch_scale;
+ u16 epoch_mult;
+ bool randomized_ds;
+
+ /* Protect both the device state for RMW and the pmu state */
+ spinlock_t lock;
+};
+
+#define pmu_to_cxl_hmu(p) container_of(p, struct cxl_hmu_info, pmu)
+
+/* destriptor for the aux buffer */
+struct cxl_hmu_buf {
+ size_t length;
+ int nr_pages;
+ void *base;
+ long pos;
+};
+
+static ssize_t cpumask_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct cxl_hmu_info *hmu = dev_get_drvdata(dev);
+
+ return cpumap_print_to_pagebuf(true, buf, cpumask_of(hmu->on_cpu));
+}
+static DEVICE_ATTR_RO(cpumask);
+
+static struct attribute *cxl_hmu_cpumask_attrs[] = {
+ &dev_attr_cpumask.attr,
+ NULL
+};
+
+static const struct attribute_group cxl_hmu_cpumask_attr_group = {
+ .attrs = cxl_hmu_cpumask_attrs,
+};
+
+/* Sized fields to future proof based on space in spec */
+PMU_FORMAT_ATTR(epoch_type, "config:0-1"); /* 2 bits to future proof */
+PMU_FORMAT_ATTR(access_type, "config:2-9");
+PMU_FORMAT_ATTR(epoch_scale, "config:10-13");
+PMU_FORMAT_ATTR(epoch_multiplier, "config:14-25");
+PMU_FORMAT_ATTR(randomized_downsampling, "config:26-26");
+PMU_FORMAT_ATTR(downsampling_factor, "config:27-34");
+
+PMU_FORMAT_ATTR(hotness_threshold, "config1:0-31");
+PMU_FORMAT_ATTR(hotness_granual, "config1:32-63");
+
+/* RFC this is a bitmap can we control it better? */
+PMU_FORMAT_ATTR(range_base, "config2:0-31");
+PMU_FORMAT_ATTR(range_size, "config2:32-63");
+static struct attribute *cxl_hmu_format_attrs[] = {
+ &format_attr_epoch_type.attr,
+ &format_attr_access_type.attr,
+ &format_attr_epoch_scale.attr,
+ &format_attr_epoch_multiplier.attr,
+ &format_attr_randomized_downsampling.attr,
+ &format_attr_downsampling_factor.attr,
+ &format_attr_hotness_threshold.attr,
+ &format_attr_hotness_granual.attr,
+ &format_attr_range_base.attr,
+ &format_attr_range_size.attr,
+ NULL
+};
+
+static struct attribute_group cxl_hmu_format_attr_group = {
+ .name = "format",
+ .attrs = cxl_hmu_format_attrs,
+};
+
+static const struct attribute_group *cxl_hmu_groups[] = {
+ &cxl_hmu_cpumask_attr_group,
+ &cxl_hmu_format_attr_group,
+ NULL
+};
+
+static int cxl_hmu_event_init(struct perf_event *event)
+{
+ struct cxl_hmu_info *hmu = pmu_to_cxl_hmu(event->pmu);
+ struct device *dev = event->pmu->dev;
+ u32 gran_sup;
+ u16 ds_sup;
+ u64 cap0, cap1;
+ u64 epoch_min, epoch_max, epoch;
+ u64 hotlist_offset = readq(hmu->base + CHMU_INST0_HOTLIST_OFFSET_REG);
+ u64 bitmap_offset = readq(hmu->base + CHMU_INST0_RANGE_BITMAP_OFFSET_REG);
+
+ if (event->attr.type != hmu->pmu.type)
+ return -ENOENT;
+
+ if (event->cpu < 0) {
+ dev_info(dev, "Per-task mode not supported\n");
+ return -EOPNOTSUPP;
+ }
+
+ if (event->attach_state & PERF_ATTACH_TASK)
+ return -EOPNOTSUPP;
+
+ cap0 = readq(hmu->base + CHMU_INST0_CAP0_REG);
+ cap1 = readq(hmu->base + CHMU_INST0_CAP1_REG);
+
+ switch (FIELD_GET(CXL_HMU_ATTR_CONFIG_EPOCH_TYPE_MASK,
+ event->attr.config)) {
+ case 0:
+ if (!FIELD_GET(CHMU_INST0_CAP1_EPOCH_SUP, cap1))
+ return -EOPNOTSUPP;
+ hmu->reporting_mode = CHMU_MODE_EPOCH;
+ break;
+ case 1:
+ if (!FIELD_GET(CHMU_INST0_CAP1_ALWAYS_ON_SUP, cap1))
+ return -EOPNOTSUPP;
+ hmu->reporting_mode = CHMU_MODE_ALWAYS_ON;
+ break;
+ default:
+ dev_dbg(dev, "Tried for a non existent type\n");
+ return -EINVAL;
+ }
+ hmu->randomized_ds = FIELD_GET(CXL_HMU_ATTR_CONFIG_RANDOM_DS_MASK,
+ event->attr.config);
+ if (hmu->randomized_ds && !FIELD_GET(CHMU_INST0_CAP1_RAND_DOWNSAMP_SUP, cap1)) {
+ dev_info(dev, "Randomized downsampling not supported\n");
+ return -EOPNOTSUPP;
+ }
+
+ /* RFC: sanity check against currently defined or not? */
+ hmu->m2s_requests_to_track = FIELD_GET(CXL_HMU_ATTR_CONFIG_ACCESS_TYPE_MASK,
+ event->attr.config);
+ if (hmu->m2s_requests_to_track < CHMU_INST0_CFG0_WHAT_NONTEE_R ||
+ hmu->m2s_requests_to_track > CHMU_INST0_CFG0_WHAT_RW) {
+ dev_dbg(dev, "Requested a reserved type to track\n");
+ return -EINVAL;
+ }
+
+ hmu->hot_thresh = FIELD_GET(CXL_HMU_ATTR_CONFIG1_HOTNESS_THRESH_MASK,
+ event->attr.config1);
+
+ hmu->hot_gran = FIELD_GET(CXL_HMU_ATTR_CONFIG1_HOTNESS_GRANUAL_MASK,
+ event->attr.config1);
+
+ gran_sup = FIELD_GET(CHMU_INST0_CAP1_UNIT_SIZE_MSK, cap1);
+ /* Default to smallest granual if not specified */
+ if (hmu->hot_gran == 0 && gran_sup)
+ hmu->hot_gran = 8 + ffs(gran_sup);
+
+ if (hmu->hot_gran < 8) {
+ dev_dbg(dev, "Granual less than 256 bytes, not valid in CXL 3.2\n");
+ return -EINVAL;
+ }
+
+ if (!((1 << (hmu->hot_gran - 8)) & gran_sup)) {
+ dev_dbg(dev, "Granual %d not supported, supported mask %x\n",
+ hmu->hot_gran - 8, gran_sup);
+ return -EOPNOTSUPP;
+ }
+
+ ds_sup = FIELD_GET(CHMU_INST0_CAP1_DOWNSAMP_MSK, cap1);
+ hmu->ds_factor_pow2 = FIELD_GET(CXL_HMU_ATTR_CONFIG_DS_FACTOR_MASK,
+ event->attr.config);
+ if (!((1 << hmu->ds_factor_pow2) & ds_sup)) {
+ /* Special case default of 0 if not supported as smallest DS possibe */
+ if (hmu->ds_factor_pow2 == 0 && ds_sup) {
+ hmu->ds_factor_pow2 = ffs(ds_sup);
+ dev_dbg(dev, "Downsampling set to default min of %d\n",
+ hmu->ds_factor_pow2);
+ } else {
+ dev_dbg(dev, "Downsampling %d no supported, supported mask %x\n",
+ hmu->ds_factor_pow2, ds_sup);
+ return -EOPNOTSUPP;
+ }
+ }
+
+ hmu->epoch_scale = FIELD_GET(CXL_HMU_ATTR_CONFIG_EPOCH_SCALE_MASK,
+ event->attr.config);
+
+ hmu->epoch_mult = FIELD_GET(CXL_HMU_ATTR_CONFIG_EPOCH_MULT_MASK,
+ event->attr.config);
+
+ /* Default to what? */
+ if (hmu->epoch_mult == 0 && hmu->epoch_scale == 0) {
+ hmu->epoch_scale = FIELD_GET(CHMU_INST0_CAP0_EPOCH_MIN_SCALE_MSK, cap0);
+ hmu->epoch_mult = FIELD_GET(CHMU_INST0_CAP0_EPOCH_MIN_MULT_MSK, cap0);
+ }
+ if (hmu->epoch_mult == 0)
+ return -EINVAL;
+
+ /* Units of 100ms */
+ epoch_min = int_pow(10, FIELD_GET(CHMU_INST0_CAP0_EPOCH_MIN_SCALE_MSK, cap0)) *
+ (u64)FIELD_GET(CHMU_INST0_CAP0_EPOCH_MIN_MULT_MSK, cap0);
+ epoch_max = int_pow(10, FIELD_GET(CHMU_INST0_CAP0_EPOCH_MAX_SCALE_MSK, cap0)) *
+ (u64)FIELD_GET(CHMU_INST0_CAP0_EPOCH_MAX_MULT_MSK, cap0);
+ epoch = int_pow(10, hmu->epoch_scale) * (u64)hmu->epoch_mult;
+
+ if (epoch > epoch_max || epoch < epoch_min) {
+ dev_dbg(dev, "out of range %llu %llu %llu\n",
+ epoch, epoch_max, epoch_min);
+ return -EINVAL;
+ }
+
+ hmu->range_base = FIELD_GET(CXL_HMU_ATTR_CONFIG2_DPA_BASE_MASK,
+ event->attr.config2);
+ hmu->range_num = FIELD_GET(CXL_HMU_ATTR_CONFIG2_DPA_SIZE_MASK,
+ event->attr.config2);
+
+ if (hmu->range_num == 0) {
+ /* Set a default of 'everything' */
+ hmu->range_num = (hotlist_offset - bitmap_offset) * 8;
+ }
+ /* TODO - pass in better DPA range info from parent driver */
+ if ((u64)hmu->range_base + hmu->range_num >
+ (hotlist_offset - bitmap_offset) * 8) {
+ dev_dbg(dev, "Requested range that this HMU can't track Can track 0x%llx, asked for 0x%x to 0x%x\n",
+ (hotlist_offset - bitmap_offset) * 8,
+ hmu->range_base, hmu->range_base + hmu->range_num);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int cxl_hmu_update_aux(struct cxl_hmu_info *hmu, bool stop)
+{
+ struct perf_output_handle *handle = &hmu->handle;
+ struct cxl_hmu_buf *buf = perf_get_aux(handle);
+ struct perf_event *event = handle->event;
+ size_t size = 0;
+ size_t tocopy, tocopy2;
+
+ u64 offset = readq(hmu->base + CHMU_INST0_HOTLIST_OFFSET_REG);
+ u16 head = readw(hmu->base + CHMU_INST0_HEAD_REG);
+ u16 tail = readw(hmu->base + CHMU_INST0_TAIL_REG);
+ u8 count_width = FIELD_GET(CHMU_INST0_STATUS_COUNTER_WIDTH_MSK,
+ readq(hmu->base + CHMU_INST0_STATUS_REG));
+ u16 top = FIELD_GET(CHMU_INST0_CAP0_HOTLIST_SIZE_MSK,
+ readq(hmu->base + CHMU_INST0_CAP0_REG));
+ /* 16 bytes of header - arbitrary choice! */
+#define CHMU_HEADER0_SIZE_MASK GENMASK(15, 0)
+#define CHMU_HEADER0_COUNT_WIDTH GENMASK(23, 16)
+ u64 header[2];
+
+ if (tail > head) {
+ tocopy = min_t(size_t, (tail - head) * 8,
+ buf->length - buf->pos - sizeof(header));
+ header[0] = FIELD_PREP(CHMU_HEADER0_SIZE_MASK, tocopy / 8) |
+ FIELD_PREP(CHMU_HEADER0_COUNT_WIDTH, count_width);
+ header[1] = 0xDEADBEEF;
+ if (tocopy) {
+ memcpy(buf->base + buf->pos, header, sizeof(header));
+ size += sizeof(header);
+ buf->pos += sizeof(header);
+ memcpy_fromio(buf->base + buf->pos,
+ hmu->base + offset + head * 8, tocopy);
+ size += tocopy;
+ buf->pos += tocopy;
+ }
+
+ } else if (tail < head) { /* wrap around */
+ tocopy = min_t(size_t, (top - head) * 8,
+ buf->length - buf->pos - sizeof(header));
+ tocopy2 = min_t(size_t, tail * 8,
+ buf->length - buf->pos - tocopy - sizeof(header));
+ header[0] = FIELD_PREP(CHMU_HEADER0_SIZE_MASK, (tocopy + tocopy2) / 8) |
+ FIELD_PREP(CHMU_HEADER0_COUNT_WIDTH, count_width);
+ header[1] = 0xDEADBEEF;
+ if (tocopy) {
+ memcpy(buf->base + buf->pos, header, sizeof(header));
+ size += sizeof(header);
+ buf->pos += sizeof(header);
+ memcpy_fromio(buf->base + buf->pos,
+ hmu->base + offset + head * 8, tocopy);
+ size += tocopy;
+ buf->pos += tocopy;
+
+ }
+
+ if (tocopy2) {
+ memcpy_fromio(buf->base + buf->pos,
+ hmu->base + offset, tocopy2);
+ size += tocopy2;
+ buf->pos += tocopy2;
+ }
+ } /* may be no data */
+
+ perf_aux_output_end(handle, size);
+ if (buf->pos == buf->length)
+ return -EINVAL; /* FULL */
+
+ /* Do this after the space check, so the buffer on device will not overwrite */
+ writew(tail, hmu->base + CHMU_INST0_HEAD_REG);
+
+ if (!stop) {
+ buf = perf_aux_output_begin(handle, event);
+ if (!buf)
+ return -EINVAL;
+ buf->pos = handle->head % buf->length;
+ }
+ return 0;
+}
+
+static int __cxl_hmu_start(struct perf_event *event, int flags)
+{
+ struct cxl_hmu_info *hmu = pmu_to_cxl_hmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ struct device *dev = event->pmu->dev;
+ struct cxl_hmu_buf *buf;
+ int cpu = event->cpu;
+ u64 val, status, bitmap_base;
+ int ret, i;
+ u16 list_len = FIELD_GET(CHMU_INST0_CAP0_HOTLIST_SIZE_MSK,
+ readq(hmu->base + CHMU_INST0_CAP0_REG));
+
+ hwc->state = 0;
+ status = readq(hmu->base + CHMU_INST0_STATUS_REG);
+ if (FIELD_GET(CHMU_INST0_STATUS_ENABLED, status)) {
+ dev_dbg(dev, "trace already started\n");
+ return -EBUSY;
+ }
+ /* TODO: Figure out what to do as very likely this is shared
+ * - Hopefully only with other HMU instances
+ */
+ ret = irq_set_affinity(hmu->irq, cpumask_of(cpu));
+ if (ret)
+ dev_warn(dev, "failed to affinity of HMU interrupt\n");
+
+ hmu->on_cpu = cpu;
+
+ buf = perf_aux_output_begin(&hmu->handle, event);
+ if (!buf) {
+ dev_dbg(event->pmu->dev, "aux output begin failed\n");
+ return -EINVAL;
+ }
+
+ buf->pos = hmu->handle.head % buf->length;
+ /* Reset here disrupts samping with -F, should we avoid doing so? */
+ writeq(FIELD_PREP(CHMU_INST0_CFG0_RESET_COUNTERS, 1),
+ hmu->base + CHMU_INST0_CFG0_REG);
+
+ ret = readq_poll_timeout_atomic(hmu->base + CHMU_INST0_STATUS_REG, status,
+ (FIELD_GET(CHMU_INST0_STATUS_OP_INPROG_MSK, status) == 0),
+ 10, 100000);
+ if (ret) {
+ dev_dbg(event->pmu->dev, "Reset timed out\n");
+ return ret;
+ }
+ /* Setup what is being capured */
+ /* Type of capture, granularity etc */
+
+ val = FIELD_PREP(CHMU_INST0_CFG1_UNIT_SIZE_MSK, hmu->hot_gran) |
+ FIELD_PREP(CHMU_INST0_CFG1_DS_FACTOR_MSK, hmu->ds_factor_pow2) |
+ FIELD_PREP(CHMU_INST0_CFG1_MODE_MSK, hmu->reporting_mode) |
+ FIELD_PREP(CHMU_INST0_CFG1_EPOCH_SCALE_MSK, hmu->epoch_scale) |
+ FIELD_PREP(CHMU_INST0_CFG1_EPOCH_MULT_MSK, hmu->epoch_mult);
+ writeq(val, hmu->base + CHMU_INST0_CFG1_REG);
+
+ val = 0;
+ bitmap_base = readq(hmu->base + CHMU_INST0_RANGE_BITMAP_OFFSET_REG);
+ for (i = hmu->range_base; i < hmu->range_base + hmu->range_num; i++) {
+ val |= BIT(i % 64);
+ if (i % 64 == 63) {
+ writeq(val, hmu->base + bitmap_base + (i / 64) * 8);
+ val = 0;
+ }
+ }
+ /* Potential duplicate write that doesn't matter */
+ writeq(val, hmu->base + bitmap_base + (i / 64) * 8);
+
+ /* Set notificaiton threshold to half of buffer */
+ val = FIELD_PREP(CHMU_INST0_CFG2_FILLTHRESH_THRESHOLD_MSK,
+ list_len / 2);
+ writeq(val, hmu->base + CHMU_INST0_CFG2_REG);
+
+ /*
+ * RFC: Only after granual is set can the width be known - so can only check here,
+ * or program granual size earlier just to see if it will work here.
+ */
+ status = readq(hmu->base + CHMU_INST0_STATUS_REG);
+ if (hmu->hot_thresh >= (1 << (64 - FIELD_GET(CHMU_INST0_STATUS_COUNTER_WIDTH_MSK, status))))
+ return -EINVAL;
+ /* Start the unit up */
+ val = FIELD_PREP(CHMU_INST0_CFG0_WHAT_MSK, hmu->m2s_requests_to_track) |
+ FIELD_PREP(CHMU_INST0_CFG0_RAND_DOWNSAMP_EN,
+ hmu->randomized_ds ? 1 : 0) |
+ FIELD_PREP(CHMU_INST0_CFG0_OVRFLW_INT_EN, 1) |
+ FIELD_PREP(CHMU_INST0_CFG0_FILLTHRESH_INT_EN, 1) |
+ FIELD_PREP(CHMU_INST0_CFG0_ENABLE, 1) |
+ FIELD_PREP(CHMU_INST0_CFG0_HOTNESS_THRESH_MSK, hmu->hot_thresh);
+ writeq(val, hmu->base + CHMU_INST0_CFG0_REG);
+
+ /* Poll status register for enablement to complete */
+ ret = readq_poll_timeout_atomic(hmu->base + CHMU_INST0_STATUS_REG, status,
+ (FIELD_GET(CHMU_INST0_STATUS_OP_INPROG_MSK, status) == 0),
+ 10, 100000);
+ if (ret) {
+ dev_info(event->pmu->dev, "Enable timed out\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static void cxl_hmu_start(struct perf_event *event, int flags)
+{
+ struct cxl_hmu_info *hmu = pmu_to_cxl_hmu(event->pmu);
+ int ret;
+
+ guard(spinlock)(&hmu->lock);
+
+ ret = __cxl_hmu_start(event, flags);
+ if (ret)
+ event->hw.state |= PERF_HES_STOPPED;
+}
+
+static void cxl_hmu_stop(struct perf_event *event, int flags)
+{
+ struct cxl_hmu_info *hmu = pmu_to_cxl_hmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ u64 status, val;
+ int ret;
+
+ if (hwc->state & PERF_HES_STOPPED)
+ return;
+
+ guard(spinlock)(&hmu->lock);
+ status = readq(hmu->base + CHMU_INST0_STATUS_REG);
+ if (FIELD_GET(CHMU_INST0_STATUS_ENABLED, status)) {
+ /* Stop the HMU instance */
+ val = readq(hmu->base + CHMU_INST0_CFG0_REG);
+ val &= ~CHMU_INST0_CFG0_ENABLE;
+ writeq(val, hmu->base + CHMU_INST0_CFG0_REG);
+
+ ret = readq_poll_timeout_atomic(hmu->base + CHMU_INST0_STATUS_REG, status,
+ (FIELD_GET(CHMU_INST0_STATUS_OP_INPROG_MSK, status) == 0),
+ 10, 100000);
+ if (ret) {
+ dev_info(event->pmu->dev, "Disable timed out\n");
+ return;
+ }
+
+ cxl_hmu_update_aux(hmu, true);
+ }
+
+}
+static void cxl_hmu_read(struct perf_event *event)
+{
+ /* Nothing to do */
+}
+
+static int cxl_hmu_add(struct perf_event *event, int flags)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+ if (flags & PERF_EF_START) {
+ cxl_hmu_start(event, PERF_EF_RELOAD);
+ if (hwc->state & PERF_HES_STOPPED)
+ return -EINVAL;
+ }
+ return 0;
+}
+
+/*
+ * There is a lot to do in here, but using a thread is not
+ * currently possible for a perf PMU driver.
+ */
+static irqreturn_t cxl_hmu_irq(int irq, void *data)
+{
+ struct cxl_hmu_info *info = data;
+ u64 status;
+ int ret;
+
+ status = readq(info->base + CHMU_INST0_STATUS_REG);
+ if (!FIELD_GET(CHMU_INST0_STATUS_OVRFLW, status) &&
+ !FIELD_GET(CHMU_INST0_STATUS_FILLTHRESH, status))
+ return IRQ_NONE;
+
+ ret = cxl_hmu_update_aux(info, false);
+ if (ret)
+ dev_err(info->pmu.dev, "interrupt update failed\n");
+
+ /*
+ * They are level interrupts so should trigger on next fill
+ * hence should be no problem with races.
+ */
+ writeq(status, info->base + CHMU_INST0_STATUS_REG);
+
+ return IRQ_HANDLED;
+}
+
+static void cxl_hmu_del(struct perf_event *event, int flags)
+{
+ cxl_hmu_stop(event, PERF_EF_UPDATE);
+}
+
+static void *cxl_hmu_setup_aux(struct perf_event *event, void **pages,
+ int nr_pages, bool overwrite)
+{
+ int i;
+
+ if (overwrite) {
+ dev_warn(event->pmu->dev, "Overwrite mode is not supported\n");
+ return NULL;
+ }
+
+ if (nr_pages < 1)
+ return NULL;
+
+ struct cxl_hmu_buf *buf __free(kfree) =
+ kzalloc(sizeof(*buf), GFP_KERNEL);
+ if (!buf)
+ return NULL;
+
+ struct page **pagelist __free(kfree) =
+ kcalloc(nr_pages, sizeof(*pagelist), GFP_KERNEL);
+ if (!pagelist)
+ return NULL;
+
+ for (i = 0; i < nr_pages; i++)
+ pagelist[i] = virt_to_page(pages[i]);
+
+ buf->base = vmap(pagelist, nr_pages, VM_MAP, PAGE_KERNEL);
+ if (!buf->base)
+ return NULL;
+
+ buf->nr_pages = nr_pages;
+ buf->length = nr_pages * PAGE_SIZE;
+ buf->pos = 0;
+
+ return_ptr(buf);
+}
+
+static void cxl_hmu_free_aux(void *aux)
+{
+ struct cxl_hmu_buf *buf = aux;
+
+ vunmap(buf->base);
+ kfree(buf);
+}
+
+static void cxl_hmu_perf_unregister(void *_info)
+{
+ struct cxl_hmu_info *info = _info;
+
+ perf_pmu_unregister(&info->pmu);
+}
+
+static void cxl_hmu_cpuhp_remove(void *_info)
+{
+ struct cxl_hmu_info *info = _info;
+
+ cpuhp_state_remove_instance_nocalls(cxl_hmu_cpuhp_state_num,
+ &info->node);
+}
+
+static int cxl_hmu_probe(struct device *dev)
+{
+ struct pci_dev *pdev = to_pci_dev(dev->parent);
+ struct cxl_hmu *hmu = to_cxl_hmu(dev);
+ int i, rc;
+
+ int num_inst = FIELD_GET(CHMU_COMMON_CAP0_NUMINST_MSK,
+ readq(hmu->base + CHMU_COMMON_CAP0_REG));
+ int inst_len = FIELD_GET(CHMU_COMMON_CAP1_INSTLEN_MSK,
+ readq(hmu->base + CHMU_COMMON_CAP1_REG));
+
+ for (i = 0; i < num_inst; i++) {
+ struct cxl_hmu_info *info;
+ char *pmu_name;
+ int msg_num;
+ u64 val;
+
+ info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ dev_set_drvdata(dev, info);
+ info->on_cpu = -1;
+ info->base = hmu->base + 0x10 + inst_len * i;
+
+ val = readq(info->base + CHMU_INST0_CAP0_REG);
+ msg_num = FIELD_GET(CHMU_INST0_CAP0_MSI_N_MSK, val);
+
+ /* TODO add polling support - for now require threshold */
+ if (!FIELD_GET(CHMU_INST0_CAP0_FILLTHRESH_CAP, val)) {
+ devm_kfree(dev, info);
+ continue;
+ }
+
+ spin_lock_init(&info->lock);
+
+ pmu_name = devm_kasprintf(dev, GFP_KERNEL,
+ "cxl_hmu_mem%d.%d.%d",
+ hmu->assoc_id, hmu->index, i);
+ if (!pmu_name)
+ return -ENOMEM;
+
+ info->pmu = (struct pmu) {
+ .name = pmu_name,
+ .parent = dev,
+ .module = THIS_MODULE,
+ .capabilities = PERF_PMU_CAP_EXCLUSIVE |
+ PERF_PMU_CAP_NO_EXCLUDE,
+ .task_ctx_nr = perf_sw_context,
+ .attr_groups = cxl_hmu_groups,
+ .event_init = cxl_hmu_event_init,
+ .setup_aux = cxl_hmu_setup_aux,
+ .free_aux = cxl_hmu_free_aux,
+ .start = cxl_hmu_start,
+ .stop = cxl_hmu_stop,
+ .add = cxl_hmu_add,
+ .del = cxl_hmu_del,
+ .read = cxl_hmu_read,
+ };
+ rc = pci_irq_vector(pdev, msg_num);
+ if (rc < 0)
+ return rc;
+ info->irq = rc;
+
+ /*
+ * Whilst there is a 'strong' recomendation that the interrupt
+ * should not be shared it is not a requirement.
+ * Can we support IRQF_SHARED on a PMU?
+ */
+ rc = devm_request_irq(dev, info->irq, cxl_hmu_irq,
+ IRQF_NO_THREAD | IRQF_NOBALANCING,
+ pmu_name, info);
+ if (rc)
+ return rc;
+
+ rc = cpuhp_state_add_instance(cxl_hmu_cpuhp_state_num,
+ &info->node);
+ if (rc)
+ return rc;
+
+ rc = devm_add_action_or_reset(dev, cxl_hmu_cpuhp_remove, info);
+ if (rc)
+ return rc;
+
+ rc = perf_pmu_register(&info->pmu, info->pmu.name, -1);
+ if (rc)
+ return rc;
+
+ rc = devm_add_action_or_reset(dev, cxl_hmu_perf_unregister,
+ info);
+ if (rc)
+ return rc;
+ }
+ return 0;
+}
+
+static struct cxl_driver cxl_hmu_driver = {
+ .name = "cxl_hmu",
+ .probe = cxl_hmu_probe,
+ .id = CXL_DEVICE_HMU,
+};
+
+static int cxl_hmu_online_cpu(unsigned int cpu, struct hlist_node *node)
+{
+ struct cxl_hmu_info *info =
+ hlist_entry_safe(node, struct cxl_hmu_info, node);
+
+ if (info->on_cpu != -1)
+ return 0;
+
+ info->on_cpu = cpu;
+
+ WARN_ON(irq_set_affinity(info->irq, cpumask_of(cpu)));
+
+ return 0;
+}
+
+static int cxl_hmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
+{
+ struct cxl_hmu_info *info =
+ hlist_entry_safe(node, struct cxl_hmu_info, node);
+ unsigned int target;
+
+ if (info->on_cpu != cpu)
+ return 0;
+
+ info->on_cpu = -1;
+ target = cpumask_any_but(cpu_online_mask, cpu);
+ if (target >= nr_cpu_ids) {
+ dev_err(info->pmu.dev, "Unable to find a suitable CPU\n");
+ return 0;
+ }
+
+ perf_pmu_migrate_context(&info->pmu, cpu, target);
+ info->on_cpu = target;
+ /*
+ * CPU HP lock is held so we should be guaranteed that this CPU hasn't
+ * yet gone away.
+ */
+ WARN_ON(irq_set_affinity(info->irq, cpumask_of(target)));
+ return 0;
+}
+
+static __init int cxl_hmu_init(void)
+{
+ int rc;
+
+ rc = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
+ "AP_PERF_CXL_HMU_ONLINE",
+ cxl_hmu_online_cpu, cxl_hmu_offline_cpu);
+ if (rc < 0)
+ return rc;
+ cxl_hmu_cpuhp_state_num = rc;
+
+ rc = cxl_driver_register(&cxl_hmu_driver);
+ if (rc)
+ cpuhp_remove_multi_state(cxl_hmu_cpuhp_state_num);
+
+ return rc;
+}
+
+static __exit void cxl_hmu_exit(void)
+{
+ cxl_driver_unregister(&cxl_hmu_driver);
+ cpuhp_remove_multi_state(cxl_hmu_cpuhp_state_num);
+}
+
+MODULE_AUTHOR("Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>");
+MODULE_DESCRIPTION("CXL Hotness Monitor Driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(CXL);
+module_init(cxl_hmu_init);
+module_exit(cxl_hmu_exit);
+MODULE_ALIAS_CXL(CXL_DEVICE_HMU);
--
2.43.0
