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Message-ID: <CABPqkBQpXAq=uk5-vx-FkYJV1nrtugit_ExFqGgQCKGQC2no6w@mail.gmail.com>
Date: Thu, 25 May 2023 18:18:55 -0700
From: Stephane Eranian <eranian@...gle.com>
To: Jonathan Cameron <jonathan.cameron@...wei.com>
Cc: Namhyung Kim <namhyung@...il.com>,
Liang Kan <kan.liang@...ux.intel.com>,
linux-cxl@...r.kernel.org, peterz@...radead.org,
mark.rutland@....com, will@...nel.org, mingo@...hat.com,
acme@...nel.org, dan.j.williams@...el.com, linuxarm@...wei.com,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
Davidlohr Bueso <dave@...olabs.net>,
Dave Jiang <dave.jiang@...el.com>
Subject: Re: [PATCH v6 4/5] perf: CXL Performance Monitoring Unit driver
On Thu, May 25, 2023 at 6:06 PM Namhyung Kim <namhyung@...il.com> wrote:
>
> Add Stephane to CC.
>
> On Thu, Apr 13, 2023 at 7:35 AM Jonathan Cameron
> <Jonathan.Cameron@...wei.com> wrote:
> >
> > CXL rev 3.0 introduces a standard performance monitoring hardware
> > block to CXL. Instances are discovered using CXL Register Locator DVSEC
> > entries. Each CXL component may have multiple PMUs.
> >
> > This initial driver supports a subset of types of counter.
> > It supports counters that are either fixed or configurable, but requires
> > that they support the ability to freeze and write value whilst frozen.
> >
> > Development done with QEMU model which will be posted shortly.
> >
> > Example:
> >
> > $ perf stat -e cxl_pmu_mem0.0/h2d_req_snpcur/ -e cpmu0/h2d_req_snpdata/ -e cpmu0/clock_ticks/ sleep 1
> >
> > Performance counter stats for 'system wide':
> >
Unless I am mistaken, I don't think this output corresponds to the
cmdline above. I think the -a is missing.
I don't think you can measure CXL traffic per-thread. Please confirm.
Thanks.
>
> > 96,757,023,244,321 cxl_pmu_mem0.0/h2d_req_snpcur/
> > 96,757,023,244,365 cxl_pmu_mem0.0/h2d_req_snpdata/
> > 193,514,046,488,653 cxl_pmu_mem0.0/clock_ticks/
> >
> > 1.090539600 seconds time elapsed
> >
> > Reviewed-by: Dave Jiang <dave.jiang@...el.com>
> > Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> >
> > ---
> > v6: Thanks to Kan again!
> > - Update PMU naming in example above.
> > - Tags applied.
> >
> > v5: Thanks to Kan Liang and Dan Williams for review.
> > - Move driver to drivers/perf and rename patch to reflect that.
> > - Add a MAINTAINERS entry now driver doesn't fall under drivers/cxl.
> > - Fix mask
> > - Drop duplication of counter reset and config writing (which also
> > gets rid of a write to an entirely read only register)
> > - Lots of cpmu->pmu and similar renames.
> > - Rename the cxl_pmu_event and related to cxl_pmu_ev_cap so as to avoid
> > impression that there is one of these for every event. They reflect the
> > event capability registers hence the new naming. Rename the two lists
> > to reflect this as well.
> > - Comments on WARN_ON cases.
> > - Fixed a bug in cpuhp offline callback where we could move to the cpu
> > that is going away.
> > - Use devm_add_action_or_reset () for remaining few bits of remove()
> > - Richer PMU naming as cxl_pmu_memX.Y to associate with
> > /sys/bus/cxl/device/memX instance of PMU Y. Scheme extents for
> > USP cxl_pmu_uspX.Y and DSP cxl_pmu_dspX.Y.Z for DSP Y of USP X,
> > PMU instance Z.
> > ---
> > MAINTAINERS | 6 +
> > drivers/cxl/Kconfig | 13 +
> > drivers/perf/Kconfig | 13 +
> > drivers/perf/Makefile | 1 +
> > drivers/perf/cxl_pmu.c | 984 +++++++++++++++++++++++++++++++++++++++++
> > 5 files changed, 1017 insertions(+)
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 90abe83c02f3..51234eb7858e 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -5174,6 +5174,12 @@ S: Maintained
> > F: drivers/cxl/
> > F: include/uapi/linux/cxl_mem.h
> >
> > +COMPUTE EXPRESS LINK PMU (CPMU)
> > +M: Jonathan Cameron <jonathan.cameron@...wei.com>
> > +L: linux-cxl@...r.kernel.org
> > +S: Maintained
> > +F: drivers/perf/cxl_pmu.c
> > +
> > CONEXANT ACCESSRUNNER USB DRIVER
> > L: accessrunner-general@...ts.sourceforge.net
> > S: Orphan
> > diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
> > index ff4e78117b31..d0a4b4cfa50c 100644
> > --- a/drivers/cxl/Kconfig
> > +++ b/drivers/cxl/Kconfig
> > @@ -139,4 +139,17 @@ config CXL_REGION_INVALIDATION_TEST
> > If unsure, or if this kernel is meant for production environments,
> > say N.
> >
> > +config CXL_PMU
> > + tristate "CXL Performance Monitoring Unit"
> > + default CXL_BUS
> > + depends on PERF_EVENTS
> > + help
> > + Support performance monitoring as defined in CXL rev 3.0
> > + section 13.2: Performance Monitoring. CXL components may have
> > + one or more CXL Performance Monitoring Units (CPMUs).
> > +
> > + Say 'y/m' to enable a driver that will attach to performance
> > + monitoring units and provide standard perf based interfaces.
> > +
> > + If unsure say 'm'.
> > endif
> > diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
> > index 66c259000a44..ffeabb14df9e 100644
> > --- a/drivers/perf/Kconfig
> > +++ b/drivers/perf/Kconfig
> > @@ -203,4 +203,17 @@ source "drivers/perf/arm_cspmu/Kconfig"
> >
> > source "drivers/perf/amlogic/Kconfig"
> >
> > +config CXL_PMU
> > + tristate "CXL Performance Monitoring Unit"
> > + depends on CXL_BUS
> > + help
> > + Support performance monitoring as defined in CXL rev 3.0
> > + section 13.2: Performance Monitoring. CXL components may have
> > + one or more CXL Performance Monitoring Units (CPMUs).
> > +
> > + Say 'y/m' to enable a driver that will attach to performance
> > + monitoring units and provide standard perf based interfaces.
> > +
> > + If unsure say 'm'.
> > +
> > endmenu
> > diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
> > index 13e45da61100..900af2c6c4f0 100644
> > --- a/drivers/perf/Makefile
> > +++ b/drivers/perf/Makefile
> > @@ -23,3 +23,4 @@ obj-$(CONFIG_APPLE_M1_CPU_PMU) += apple_m1_cpu_pmu.o
> > obj-$(CONFIG_ALIBABA_UNCORE_DRW_PMU) += alibaba_uncore_drw_pmu.o
> > obj-$(CONFIG_ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU) += arm_cspmu/
> > obj-$(CONFIG_MESON_DDR_PMU) += amlogic/
> > +obj-$(CONFIG_CXL_PMU) += cxl_pmu.o
> > diff --git a/drivers/perf/cxl_pmu.c b/drivers/perf/cxl_pmu.c
> > new file mode 100644
> > index 000000000000..29d8b64a11b6
> > --- /dev/null
> > +++ b/drivers/perf/cxl_pmu.c
> > @@ -0,0 +1,984 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +/*
> > + * Copyright(c) 2023 Huawei
> > + *
> > + * The CXL 3.0 specification includes a standard Performance Monitoring Unit,
> > + * called the CXL PMU, or CPMU. In order to allow a high degree of
> > + * implementation flexibility the specification provides a wide range of
> > + * options all of which are self describing.
> > + *
> > + * Details in CXL rev 3.0 section 8.2.7 CPMU Register Interface
> > + */
> > +
> > +#include <linux/io-64-nonatomic-lo-hi.h>
> > +#include <linux/perf_event.h>
> > +#include <linux/bitops.h>
> > +#include <linux/device.h>
> > +#include <linux/bits.h>
> > +#include <linux/list.h>
> > +#include <linux/bug.h>
> > +#include <linux/pci.h>
> > +
> > +#include "../cxl/cxlpci.h"
> > +#include "../cxl/cxl.h"
> > +#include "../cxl/pmu.h"
> > +
> > +#define CXL_PMU_CAP_REG 0x0
> > +#define CXL_PMU_CAP_NUM_COUNTERS_MSK GENMASK_ULL(4, 0)
> > +#define CXL_PMU_CAP_COUNTER_WIDTH_MSK GENMASK_ULL(15, 8)
> > +#define CXL_PMU_CAP_NUM_EVN_CAP_REG_SUP_MSK GENMASK_ULL(24, 20)
> > +#define CXL_PMU_CAP_FILTERS_SUP_MSK GENMASK_ULL(39, 32)
> > +#define CXL_PMU_FILTER_HDM BIT(0)
> > +#define CXL_PMU_FILTER_CHAN_RANK_BANK BIT(1)
> > +#define CXL_PMU_CAP_MSI_N_MSK GENMASK_ULL(47, 44)
> > +#define CXL_PMU_CAP_WRITEABLE_WHEN_FROZEN BIT_ULL(48)
> > +#define CXL_PMU_CAP_FREEZE BIT_ULL(49)
> > +#define CXL_PMU_CAP_INT BIT_ULL(50)
> > +#define CXL_PMU_CAP_VERSION_MSK GENMASK_ULL(63, 60)
> > +
> > +#define CXL_PMU_OVERFLOW_REG 0x10
> > +#define CXL_PMU_FREEZE_REG 0x18
> > +#define CXL_PMU_EVENT_CAP_REG(n) (0x100 + 8 * (n))
> > +#define CXL_PMU_EVENT_CAP_SUPPORTED_EVENTS_MSK GENMASK_ULL(31, 0)
> > +#define CXL_PMU_EVENT_CAP_GROUP_ID_MSK GENMASK_ULL(47, 32)
> > +#define CXL_PMU_EVENT_CAP_VENDOR_ID_MSK GENMASK_ULL(63, 48)
> > +
> > +#define CXL_PMU_COUNTER_CFG_REG(n) (0x200 + 8 * (n))
> > +#define CXL_PMU_COUNTER_CFG_TYPE_MSK GENMASK_ULL(1, 0)
> > +#define CXL_PMU_COUNTER_CFG_TYPE_FREE_RUN 0
> > +#define CXL_PMU_COUNTER_CFG_TYPE_FIXED_FUN 1
> > +#define CXL_PMU_COUNTER_CFG_TYPE_CONFIGURABLE 2
> > +#define CXL_PMU_COUNTER_CFG_ENABLE BIT_ULL(8)
> > +#define CXL_PMU_COUNTER_CFG_INT_ON_OVRFLW BIT_ULL(9)
> > +#define CXL_PMU_COUNTER_CFG_FREEZE_ON_OVRFLW BIT_ULL(10)
> > +#define CXL_PMU_COUNTER_CFG_EDGE BIT_ULL(11)
> > +#define CXL_PMU_COUNTER_CFG_INVERT BIT_ULL(12)
> > +#define CXL_PMU_COUNTER_CFG_THRESHOLD_MSK GENMASK_ULL(23, 16)
> > +#define CXL_PMU_COUNTER_CFG_EVENTS_MSK GENMASK_ULL(55, 24)
> > +#define CXL_PMU_COUNTER_CFG_EVENT_GRP_ID_IDX_MSK GENMASK_ULL(63, 59)
> > +
> > +#define CXL_PMU_FILTER_CFG_REG(n, f) (0x400 + 4 * ((f) + (n) * 8))
> > +#define CXL_PMU_FILTER_CFG_VALUE_MSK GENMASK(15, 0)
> > +
> > +#define CXL_PMU_COUNTER_REG(n) (0xc00 + 8 * (n))
> > +
> > +/* CXL rev 3.0 Table 13-5 Events under CXL Vendor ID */
> > +#define CXL_PMU_GID_CLOCK_TICKS 0x00
> > +#define CXL_PMU_GID_D2H_REQ 0x0010
> > +#define CXL_PMU_GID_D2H_RSP 0x0011
> > +#define CXL_PMU_GID_H2D_REQ 0x0012
> > +#define CXL_PMU_GID_H2D_RSP 0x0013
> > +#define CXL_PMU_GID_CACHE_DATA 0x0014
> > +#define CXL_PMU_GID_M2S_REQ 0x0020
> > +#define CXL_PMU_GID_M2S_RWD 0x0021
> > +#define CXL_PMU_GID_M2S_BIRSP 0x0022
> > +#define CXL_PMU_GID_S2M_BISNP 0x0023
> > +#define CXL_PMU_GID_S2M_NDR 0x0024
> > +#define CXL_PMU_GID_S2M_DRS 0x0025
> > +#define CXL_PMU_GID_DDR 0x8000
> > +
> > +static int cxl_pmu_cpuhp_state_num;
> > +
> > +struct cxl_pmu_ev_cap {
> > + u16 vid;
> > + u16 gid;
> > + u32 msk;
> > + union {
> > + int counter_idx; /* fixed counters */
> > + int event_idx; /* configurable counters */
> > + };
> > + struct list_head node;
> > +};
> > +
> > +#define CXL_PMU_MAX_COUNTERS 64
> > +struct cxl_pmu_info {
> > + struct pmu pmu;
> > + void __iomem *base;
> > + struct perf_event **hw_events;
> > + struct list_head event_caps_configurable;
> > + struct list_head event_caps_fixed;
> > + DECLARE_BITMAP(used_counter_bm, CXL_PMU_MAX_COUNTERS);
> > + DECLARE_BITMAP(conf_counter_bm, CXL_PMU_MAX_COUNTERS);
> > + u16 counter_width;
> > + u8 num_counters;
> > + u8 num_event_capabilities;
> > + int on_cpu;
> > + struct hlist_node node;
> > + bool filter_hdm;
> > + int irq;
> > +};
> > +
> > +#define pmu_to_cxl_pmu_info(_pmu) container_of(_pmu, struct cxl_pmu_info, pmu)
> > +
> > +/*
> > + * All CPMU counters are discoverable via the Event Capabilities Registers.
> > + * Each Event Capability register contains a a VID / GroupID.
> > + * A counter may then count any combination (by summing) of events in
> > + * that group which are in the Supported Events Bitmask.
> > + * However, there are some complexities to the scheme.
> > + * - Fixed function counters refer to an Event Capabilities register.
> > + * That event capability register is not then used for Configurable
> > + * counters.
> > + */
> > +static int cxl_pmu_parse_caps(struct device *dev, struct cxl_pmu_info *info)
> > +{
> > + unsigned long fixed_counter_event_cap_bm = 0;
> > + void __iomem *base = info->base;
> > + bool freeze_for_enable;
> > + u64 val, eval;
> > + int i;
> > +
> > + val = readq(base + CXL_PMU_CAP_REG);
> > + freeze_for_enable = FIELD_GET(CXL_PMU_CAP_WRITEABLE_WHEN_FROZEN, val) &&
> > + FIELD_GET(CXL_PMU_CAP_FREEZE, val);
> > + if (!freeze_for_enable) {
> > + dev_err(dev, "Counters not writable while frozen\n");
> > + return -ENODEV;
> > + }
> > +
> > + info->num_counters = FIELD_GET(CXL_PMU_CAP_NUM_COUNTERS_MSK, val) + 1;
> > + info->counter_width = FIELD_GET(CXL_PMU_CAP_COUNTER_WIDTH_MSK, val);
> > + info->num_event_capabilities = FIELD_GET(CXL_PMU_CAP_NUM_EVN_CAP_REG_SUP_MSK, val) + 1;
> > +
> > + info->filter_hdm = FIELD_GET(CXL_PMU_CAP_FILTERS_SUP_MSK, val) & CXL_PMU_FILTER_HDM;
> > + if (FIELD_GET(CXL_PMU_CAP_INT, val))
> > + info->irq = FIELD_GET(CXL_PMU_CAP_MSI_N_MSK, val);
> > + else
> > + info->irq = -1;
> > +
> > + /* First handle fixed function counters; note if configurable counters found */
> > + for (i = 0; i < info->num_counters; i++) {
> > + struct cxl_pmu_ev_cap *pmu_ev;
> > + u32 events_msk;
> > + u8 group_idx;
> > +
> > + val = readq(base + CXL_PMU_COUNTER_CFG_REG(i));
> > +
> > + if (FIELD_GET(CXL_PMU_COUNTER_CFG_TYPE_MSK, val) ==
> > + CXL_PMU_COUNTER_CFG_TYPE_CONFIGURABLE) {
> > + set_bit(i, info->conf_counter_bm);
> > + }
> > +
> > + if (FIELD_GET(CXL_PMU_COUNTER_CFG_TYPE_MSK, val) !=
> > + CXL_PMU_COUNTER_CFG_TYPE_FIXED_FUN)
> > + continue;
> > +
> > + /* In this case we know which fields are const */
> > + group_idx = FIELD_GET(CXL_PMU_COUNTER_CFG_EVENT_GRP_ID_IDX_MSK, val);
> > + events_msk = FIELD_GET(CXL_PMU_COUNTER_CFG_EVENTS_MSK, val);
> > + eval = readq(base + CXL_PMU_EVENT_CAP_REG(group_idx));
> > + pmu_ev = devm_kzalloc(dev, sizeof(*pmu_ev), GFP_KERNEL);
> > + if (!pmu_ev)
> > + return -ENOMEM;
> > +
> > + pmu_ev->vid = FIELD_GET(CXL_PMU_EVENT_CAP_VENDOR_ID_MSK, eval);
> > + pmu_ev->gid = FIELD_GET(CXL_PMU_EVENT_CAP_GROUP_ID_MSK, eval);
> > + /* For a fixed purpose counter use the events mask from the counter CFG */
> > + pmu_ev->msk = events_msk;
> > + pmu_ev->counter_idx = i;
> > + /* This list add is never unwound as all entries deleted on remove */
> > + list_add(&pmu_ev->node, &info->event_caps_fixed);
> > + /*
> > + * Configurable counters must not use an Event Capability registers that
> > + * is in use for a Fixed counter
> > + */
> > + set_bit(group_idx, &fixed_counter_event_cap_bm);
> > + }
> > +
> > + if (!bitmap_empty(info->conf_counter_bm, CXL_PMU_MAX_COUNTERS)) {
> > + struct cxl_pmu_ev_cap *pmu_ev;
> > + int j;
> > + /* Walk event capabilities unused by fixed counters */
> > + for_each_clear_bit(j, &fixed_counter_event_cap_bm,
> > + info->num_event_capabilities) {
> > + pmu_ev = devm_kzalloc(dev, sizeof(*pmu_ev), GFP_KERNEL);
> > + if (!pmu_ev)
> > + return -ENOMEM;
> > +
> > + eval = readq(base + CXL_PMU_EVENT_CAP_REG(j));
> > + pmu_ev->vid = FIELD_GET(CXL_PMU_EVENT_CAP_VENDOR_ID_MSK, eval);
> > + pmu_ev->gid = FIELD_GET(CXL_PMU_EVENT_CAP_GROUP_ID_MSK, eval);
> > + pmu_ev->msk = FIELD_GET(CXL_PMU_EVENT_CAP_SUPPORTED_EVENTS_MSK, eval);
> > + pmu_ev->event_idx = j;
> > + list_add(&pmu_ev->node, &info->event_caps_configurable);
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static ssize_t cxl_pmu_format_sysfs_show(struct device *dev,
> > + struct device_attribute *attr, char *buf)
> > +{
> > + struct dev_ext_attribute *eattr;
> > +
> > + eattr = container_of(attr, struct dev_ext_attribute, attr);
> > +
> > + return sysfs_emit(buf, "%s\n", (char *)eattr->var);
> > +}
> > +
> > +#define CXL_PMU_FORMAT_ATTR(_name, _format)\
> > + (&((struct dev_ext_attribute[]) { \
> > + { \
> > + .attr = __ATTR(_name, 0444, \
> > + cxl_pmu_format_sysfs_show, NULL), \
> > + .var = (void *)_format \
> > + } \
> > + })[0].attr.attr)
> > +
> > +enum {
> > + cxl_pmu_mask_attr,
> > + cxl_pmu_gid_attr,
> > + cxl_pmu_vid_attr,
> > + cxl_pmu_threshold_attr,
> > + cxl_pmu_invert_attr,
> > + cxl_pmu_edge_attr,
> > + cxl_pmu_hdm_filter_en_attr,
> > + cxl_pmu_hdm_attr,
> > +};
> > +
> > +static struct attribute *cxl_pmu_format_attr[] = {
> > + [cxl_pmu_mask_attr] = CXL_PMU_FORMAT_ATTR(mask, "config:0-31"),
> > + [cxl_pmu_gid_attr] = CXL_PMU_FORMAT_ATTR(gid, "config:32-47"),
> > + [cxl_pmu_vid_attr] = CXL_PMU_FORMAT_ATTR(vid, "config:48-63"),
> > + [cxl_pmu_threshold_attr] = CXL_PMU_FORMAT_ATTR(threshold, "config1:0-15"),
> > + [cxl_pmu_invert_attr] = CXL_PMU_FORMAT_ATTR(invert, "config1:16"),
> > + [cxl_pmu_edge_attr] = CXL_PMU_FORMAT_ATTR(edge, "config1:17"),
> > + [cxl_pmu_hdm_filter_en_attr] = CXL_PMU_FORMAT_ATTR(hdm_filter_en, "config1:18"),
> > + [cxl_pmu_hdm_attr] = CXL_PMU_FORMAT_ATTR(hdm, "config2:0-15"),
> > + NULL
> > +};
> > +
> > +#define CXL_PMU_ATTR_CONFIG_MASK_MSK GENMASK_ULL(31, 0)
> > +#define CXL_PMU_ATTR_CONFIG_GID_MSK GENMASK_ULL(47, 32)
> > +#define CXL_PMU_ATTR_CONFIG_VID_MSK GENMASK_ULL(63, 48)
> > +#define CXL_PMU_ATTR_CONFIG1_THRESHOLD_MSK GENMASK_ULL(15, 0)
> > +#define CXL_PMU_ATTR_CONFIG1_INVERT_MSK BIT(16)
> > +#define CXL_PMU_ATTR_CONFIG1_EDGE_MSK BIT(17)
> > +#define CXL_PMU_ATTR_CONFIG1_FILTER_EN_MSK BIT(18)
> > +#define CXL_PMU_ATTR_CONFIG2_HDM_MSK GENMASK(15, 0)
> > +
> > +static umode_t cxl_pmu_format_is_visible(struct kobject *kobj,
> > + struct attribute *attr, int a)
> > +{
> > + struct device *dev = kobj_to_dev(kobj);
> > + struct cxl_pmu_info *info = dev_get_drvdata(dev);
> > +
> > + /*
> > + * Filter capability at the CPMU level, so hide the attributes if the particular
> > + * filter is not supported.
> > + */
> > + if (!info->filter_hdm &&
> > + (attr == cxl_pmu_format_attr[cxl_pmu_hdm_filter_en_attr] ||
> > + attr == cxl_pmu_format_attr[cxl_pmu_hdm_attr]))
> > + return 0;
> > +
> > + return attr->mode;
> > +}
> > +
> > +static const struct attribute_group cxl_pmu_format_group = {
> > + .name = "format",
> > + .attrs = cxl_pmu_format_attr,
> > + .is_visible = cxl_pmu_format_is_visible,
> > +};
> > +
> > +static u32 cxl_pmu_config_get_mask(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG_MASK_MSK, event->attr.config);
> > +}
> > +
> > +static u16 cxl_pmu_config_get_gid(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG_GID_MSK, event->attr.config);
> > +}
> > +
> > +static u16 cxl_pmu_config_get_vid(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG_VID_MSK, event->attr.config);
> > +}
> > +
> > +static u8 cxl_pmu_config1_get_threshold(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG1_THRESHOLD_MSK, event->attr.config1);
> > +}
> > +
> > +static bool cxl_pmu_config1_get_invert(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG1_INVERT_MSK, event->attr.config1);
> > +}
> > +
> > +static bool cxl_pmu_config1_get_edge(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG1_EDGE_MSK, event->attr.config1);
> > +}
> > +
> > +/*
> > + * CPMU specification allows for 8 filters, each with a 16 bit value...
> > + * So we need to find 8x16bits to store it in.
> > + * As the value used for disable is 0xffff, a separate enable switch
> > + * is needed.
> > + */
> > +
> > +static bool cxl_pmu_config1_hdm_filter_en(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG1_FILTER_EN_MSK, event->attr.config1);
> > +}
> > +
> > +static u16 cxl_pmu_config2_get_hdm_decoder(struct perf_event *event)
> > +{
> > + return FIELD_GET(CXL_PMU_ATTR_CONFIG2_HDM_MSK, event->attr.config2);
> > +}
> > +
> > +static ssize_t cxl_pmu_event_sysfs_show(struct device *dev,
> > + struct device_attribute *attr, char *buf)
> > +{
> > + struct perf_pmu_events_attr *pmu_attr =
> > + container_of(attr, struct perf_pmu_events_attr, attr);
> > +
> > + return sysfs_emit(buf, "config=%#llx\n", pmu_attr->id);
> > +}
> > +
> > +#define CXL_PMU_EVENT_ATTR(_name, _vid, _gid, _msk) \
> > + PMU_EVENT_ATTR_ID(_name, cxl_pmu_event_sysfs_show, \
> > + ((u64)(_vid) << 48) | ((u64)(_gid) << 32) | (u64)(_msk))
> > +
> > +/* For CXL spec defined events */
> > +#define CXL_PMU_EVENT_CXL_ATTR(_name, _gid, _msk) \
> > + CXL_PMU_EVENT_ATTR(_name, PCI_DVSEC_VENDOR_ID_CXL, _gid, _msk)
> > +
> > +static struct attribute *cxl_pmu_event_attrs[] = {
> > + CXL_PMU_EVENT_CXL_ATTR(clock_ticks, CXL_PMU_GID_CLOCK_TICKS, BIT(0)),
> > + /* CXL rev 3.0 Table 3-17 - Device to Host Requests */
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_rdcurr, CXL_PMU_GID_D2H_REQ, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_rdown, CXL_PMU_GID_D2H_REQ, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_rdshared, CXL_PMU_GID_D2H_REQ, BIT(3)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_rdany, CXL_PMU_GID_D2H_REQ, BIT(4)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_rdownnodata, CXL_PMU_GID_D2H_REQ, BIT(5)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_itomwr, CXL_PMU_GID_D2H_REQ, BIT(6)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_wrcurr, CXL_PMU_GID_D2H_REQ, BIT(7)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_clflush, CXL_PMU_GID_D2H_REQ, BIT(8)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_cleanevict, CXL_PMU_GID_D2H_REQ, BIT(9)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_dirtyevict, CXL_PMU_GID_D2H_REQ, BIT(10)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_cleanevictnodata, CXL_PMU_GID_D2H_REQ, BIT(11)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_wowrinv, CXL_PMU_GID_D2H_REQ, BIT(12)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_wowrinvf, CXL_PMU_GID_D2H_REQ, BIT(13)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_wrinv, CXL_PMU_GID_D2H_REQ, BIT(14)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_req_cacheflushed, CXL_PMU_GID_D2H_REQ, BIT(16)),
> > + /* CXL rev 3.0 Table 3-20 - D2H Repsonse Encodings */
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_rsp_rspihiti, CXL_PMU_GID_D2H_RSP, BIT(4)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_rsp_rspvhitv, CXL_PMU_GID_D2H_RSP, BIT(6)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_rsp_rspihitse, CXL_PMU_GID_D2H_RSP, BIT(5)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_rsp_rspshitse, CXL_PMU_GID_D2H_RSP, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_rsp_rspsfwdm, CXL_PMU_GID_D2H_RSP, BIT(7)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_rsp_rspifwdm, CXL_PMU_GID_D2H_RSP, BIT(15)),
> > + CXL_PMU_EVENT_CXL_ATTR(d2h_rsp_rspvfwdv, CXL_PMU_GID_D2H_RSP, BIT(22)),
> > + /* CXL rev 3.0 Table 3-21 - CXL.cache - Mapping of H2D Requests to D2H Responses */
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_req_snpdata, CXL_PMU_GID_H2D_REQ, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_req_snpinv, CXL_PMU_GID_H2D_REQ, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_req_snpcur, CXL_PMU_GID_H2D_REQ, BIT(3)),
> > + /* CXL rev 3.0 Table 3-22 - H2D Response Opcode Encodings */
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_rsp_writepull, CXL_PMU_GID_H2D_RSP, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_rsp_go, CXL_PMU_GID_H2D_RSP, BIT(4)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_rsp_gowritepull, CXL_PMU_GID_H2D_RSP, BIT(5)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_rsp_extcmp, CXL_PMU_GID_H2D_RSP, BIT(6)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_rsp_gowritepulldrop, CXL_PMU_GID_H2D_RSP, BIT(8)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_rsp_fastgowritepull, CXL_PMU_GID_H2D_RSP, BIT(13)),
> > + CXL_PMU_EVENT_CXL_ATTR(h2d_rsp_goerrwritepull, CXL_PMU_GID_H2D_RSP, BIT(15)),
> > + /* CXL rev 3.0 Table 13-5 directly lists these */
> > + CXL_PMU_EVENT_CXL_ATTR(cachedata_d2h_data, CXL_PMU_GID_CACHE_DATA, BIT(0)),
> > + CXL_PMU_EVENT_CXL_ATTR(cachedata_h2d_data, CXL_PMU_GID_CACHE_DATA, BIT(1)),
> > + /* CXL rev 3.0 Table 3-29 M2S Req Memory Opcodes */
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_meminv, CXL_PMU_GID_M2S_REQ, BIT(0)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_memrd, CXL_PMU_GID_M2S_REQ, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_memrddata, CXL_PMU_GID_M2S_REQ, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_memrdfwd, CXL_PMU_GID_M2S_REQ, BIT(3)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_memwrfwd, CXL_PMU_GID_M2S_REQ, BIT(4)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_memspecrd, CXL_PMU_GID_M2S_REQ, BIT(8)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_meminvnt, CXL_PMU_GID_M2S_REQ, BIT(9)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_req_memcleanevict, CXL_PMU_GID_M2S_REQ, BIT(10)),
> > + /* CXL rev 3.0 Table 3-35 M2S RwD Memory Opcodes */
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_rwd_memwr, CXL_PMU_GID_M2S_RWD, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_rwd_memwrptl, CXL_PMU_GID_M2S_RWD, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_rwd_biconflict, CXL_PMU_GID_M2S_RWD, BIT(4)),
> > + /* CXL rev 3.0 Table 3-38 M2S BIRsp Memory Opcodes */
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_birsp_i, CXL_PMU_GID_M2S_BIRSP, BIT(0)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_birsp_s, CXL_PMU_GID_M2S_BIRSP, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_birsp_e, CXL_PMU_GID_M2S_BIRSP, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_birsp_iblk, CXL_PMU_GID_M2S_BIRSP, BIT(4)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_birsp_sblk, CXL_PMU_GID_M2S_BIRSP, BIT(5)),
> > + CXL_PMU_EVENT_CXL_ATTR(m2s_birsp_eblk, CXL_PMU_GID_M2S_BIRSP, BIT(6)),
> > + /* CXL rev 3.0 Table 3-40 S2M BISnp Opcodes */
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_bisnp_cur, CXL_PMU_GID_S2M_BISNP, BIT(0)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_bisnp_data, CXL_PMU_GID_S2M_BISNP, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_bisnp_inv, CXL_PMU_GID_S2M_BISNP, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_bisnp_curblk, CXL_PMU_GID_S2M_BISNP, BIT(4)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_bisnp_datblk, CXL_PMU_GID_S2M_BISNP, BIT(5)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_bisnp_invblk, CXL_PMU_GID_S2M_BISNP, BIT(6)),
> > + /* CXL rev 3.0 Table 3-43 S2M NDR Opcopdes */
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_ndr_cmp, CXL_PMU_GID_S2M_NDR, BIT(0)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_ndr_cmps, CXL_PMU_GID_S2M_NDR, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_ndr_cmpe, CXL_PMU_GID_S2M_NDR, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_ndr_biconflictack, CXL_PMU_GID_S2M_NDR, BIT(3)),
> > + /* CXL rev 3.0 Table 3-46 S2M DRS opcodes */
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_drs_memdata, CXL_PMU_GID_S2M_DRS, BIT(0)),
> > + CXL_PMU_EVENT_CXL_ATTR(s2m_drs_memdatanxm, CXL_PMU_GID_S2M_DRS, BIT(1)),
> > + /* CXL rev 3.0 Table 13-5 directly lists these */
> > + CXL_PMU_EVENT_CXL_ATTR(ddr_act, CXL_PMU_GID_DDR, BIT(0)),
> > + CXL_PMU_EVENT_CXL_ATTR(ddr_pre, CXL_PMU_GID_DDR, BIT(1)),
> > + CXL_PMU_EVENT_CXL_ATTR(ddr_casrd, CXL_PMU_GID_DDR, BIT(2)),
> > + CXL_PMU_EVENT_CXL_ATTR(ddr_caswr, CXL_PMU_GID_DDR, BIT(3)),
> > + CXL_PMU_EVENT_CXL_ATTR(ddr_refresh, CXL_PMU_GID_DDR, BIT(4)),
> > + CXL_PMU_EVENT_CXL_ATTR(ddr_selfrefreshent, CXL_PMU_GID_DDR, BIT(5)),
> > + CXL_PMU_EVENT_CXL_ATTR(ddr_rfm, CXL_PMU_GID_DDR, BIT(6)),
> > + NULL
> > +};
> > +
> > +static struct cxl_pmu_ev_cap *cxl_pmu_find_fixed_counter_ev_cap(struct cxl_pmu_info *info,
> > + int vid, int gid, int msk)
> > +{
> > + struct cxl_pmu_ev_cap *pmu_ev;
> > +
> > + list_for_each_entry(pmu_ev, &info->event_caps_fixed, node) {
> > + if (vid != pmu_ev->vid || gid != pmu_ev->gid)
> > + continue;
> > +
> > + /* Precise match for fixed counter */
> > + if (msk == pmu_ev->msk)
> > + return pmu_ev;
> > + }
> > +
> > + return ERR_PTR(-EINVAL);
> > +}
> > +
> > +static struct cxl_pmu_ev_cap *cxl_pmu_find_config_counter_ev_cap(struct cxl_pmu_info *info,
> > + int vid, int gid, int msk)
> > +{
> > + struct cxl_pmu_ev_cap *pmu_ev;
> > +
> > + list_for_each_entry(pmu_ev, &info->event_caps_configurable, node) {
> > + if (vid != pmu_ev->vid || gid != pmu_ev->gid)
> > + continue;
> > +
> > + /* Request mask must be subset of supported */
> > + if (msk & ~pmu_ev->msk)
> > + continue;
> > +
> > + return pmu_ev;
> > + }
> > +
> > + return ERR_PTR(-EINVAL);
> > +}
> > +
> > +static umode_t cxl_pmu_event_is_visible(struct kobject *kobj, struct attribute *attr, int a)
> > +{
> > + struct device_attribute *dev_attr = container_of(attr, struct device_attribute, attr);
> > + struct perf_pmu_events_attr *pmu_attr =
> > + container_of(dev_attr, struct perf_pmu_events_attr, attr);
> > + struct device *dev = kobj_to_dev(kobj);
> > + struct cxl_pmu_info *info = dev_get_drvdata(dev);
> > + int vid = FIELD_GET(CXL_PMU_ATTR_CONFIG_VID_MSK, pmu_attr->id);
> > + int gid = FIELD_GET(CXL_PMU_ATTR_CONFIG_GID_MSK, pmu_attr->id);
> > + int msk = FIELD_GET(CXL_PMU_ATTR_CONFIG_MASK_MSK, pmu_attr->id);
> > +
> > + if (!IS_ERR(cxl_pmu_find_fixed_counter_ev_cap(info, vid, gid, msk)))
> > + return attr->mode;
> > +
> > + if (!IS_ERR(cxl_pmu_find_config_counter_ev_cap(info, vid, gid, msk)))
> > + return attr->mode;
> > +
> > + return 0;
> > +}
> > +
> > +static const struct attribute_group cxl_pmu_events = {
> > + .name = "events",
> > + .attrs = cxl_pmu_event_attrs,
> > + .is_visible = cxl_pmu_event_is_visible,
> > +};
> > +
> > +static ssize_t cpumask_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct cxl_pmu_info *info = dev_get_drvdata(dev);
> > +
> > + return cpumap_print_to_pagebuf(true, buf, cpumask_of(info->on_cpu));
> > +}
> > +static DEVICE_ATTR_RO(cpumask);
> > +
> > +static struct attribute *cxl_pmu_cpumask_attrs[] = {
> > + &dev_attr_cpumask.attr,
> > + NULL
> > +};
> > +
> > +static const struct attribute_group cxl_pmu_cpumask_group = {
> > + .attrs = cxl_pmu_cpumask_attrs,
> > +};
> > +
> > +static const struct attribute_group *cxl_pmu_attr_groups[] = {
> > + &cxl_pmu_events,
> > + &cxl_pmu_format_group,
> > + &cxl_pmu_cpumask_group,
> > + NULL
> > +};
> > +
> > +/* If counter_idx == NULL, don't try to allocate a counter. */
> > +static int cxl_pmu_get_event_idx(struct perf_event *event, int *counter_idx,
> > + int *event_idx)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > + DECLARE_BITMAP(configurable_and_free, CXL_PMU_MAX_COUNTERS);
> > + struct cxl_pmu_ev_cap *pmu_ev;
> > + u32 mask;
> > + u16 gid, vid;
> > + int i;
> > +
> > + vid = cxl_pmu_config_get_vid(event);
> > + gid = cxl_pmu_config_get_gid(event);
> > + mask = cxl_pmu_config_get_mask(event);
> > +
> > + pmu_ev = cxl_pmu_find_fixed_counter_ev_cap(info, vid, gid, mask);
> > + if (!IS_ERR(pmu_ev)) {
> > + if (!counter_idx)
> > + return 0;
> > + if (!test_bit(pmu_ev->counter_idx, info->used_counter_bm)) {
> > + *counter_idx = pmu_ev->counter_idx;
> > + return 0;
> > + }
> > + /* Fixed counter is in use, but maybe a configurable one? */
> > + }
> > +
> > + pmu_ev = cxl_pmu_find_config_counter_ev_cap(info, vid, gid, mask);
> > + if (!IS_ERR(pmu_ev)) {
> > + if (!counter_idx)
> > + return 0;
> > +
> > + bitmap_andnot(configurable_and_free, info->conf_counter_bm,
> > + info->used_counter_bm, CXL_PMU_MAX_COUNTERS);
> > +
> > + i = find_first_bit(configurable_and_free, CXL_PMU_MAX_COUNTERS);
> > + if (i == CXL_PMU_MAX_COUNTERS)
> > + return -EINVAL;
> > +
> > + *counter_idx = i;
> > + return 0;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static int cxl_pmu_event_init(struct perf_event *event)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > +
> > + event->cpu = info->on_cpu;
>
> Why not change the event->cpu after validation is done?
>
> Thanks,
> Namhyung
>
>
> > + /* Top level type sanity check - is this a Hardware Event being requested */
> > + if (event->attr.type != event->pmu->type)
> > + return -ENOENT;
> > +
> > + if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
> > + return -EOPNOTSUPP;
> > + /* TODO: Validation of any filter */
> > +
> > + /*
> > + * Verify that it is possible to count what was requested. Either must
> > + * be a fixed counter that is a precise match or a configurable counter
> > + * where this is a subset.
> > + */
> > + return cxl_pmu_get_event_idx(event, NULL, NULL);
> > +}
> > +
> > +static void cxl_pmu_enable(struct pmu *pmu)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(pmu);
> > + void __iomem *base = info->base;
> > +
> > + /* Can assume frozen at this stage */
> > + writeq(0, base + CXL_PMU_FREEZE_REG);
> > +}
> > +
> > +static void cxl_pmu_disable(struct pmu *pmu)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(pmu);
> > + void __iomem *base = info->base;
> > +
> > + /*
> > + * Whilst bits above number of counters are RsvdZ
> > + * they are unlikely to be repurposed given
> > + * number of counters is allowed to be 64 leaving
> > + * no reserved bits. Hence this is only slightly
> > + * naughty.
> > + */
> > + writeq(GENMASK_ULL(63, 0), base + CXL_PMU_FREEZE_REG);
> > +}
> > +
> > +static void cxl_pmu_event_start(struct perf_event *event, int flags)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > + struct hw_perf_event *hwc = &event->hw;
> > + void __iomem *base = info->base;
> > + u64 cfg;
> > +
> > + /*
> > + * All paths to here should either set these flags directly or
> > + * call cxl_pmu_event_stop() which will ensure the correct state.
> > + */
> > + if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
> > + return;
> > +
> > + WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
> > + hwc->state = 0;
> > +
> > + /*
> > + * Currently only hdm filter control is implemnted, this code will
> > + * want generalizing when more filters are added.
> > + */
> > + if (info->filter_hdm) {
> > + if (cxl_pmu_config1_hdm_filter_en(event))
> > + cfg = cxl_pmu_config2_get_hdm_decoder(event);
> > + else
> > + cfg = GENMASK(15, 0); /* No filtering if 0xFFFF_FFFF */
> > + writeq(cfg, base + CXL_PMU_FILTER_CFG_REG(hwc->idx, 0));
> > + }
> > +
> > + cfg = readq(base + CXL_PMU_COUNTER_CFG_REG(hwc->idx));
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_INT_ON_OVRFLW, 1);
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_FREEZE_ON_OVRFLW, 1);
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_ENABLE, 1);
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_EDGE,
> > + cxl_pmu_config1_get_edge(event) ? 1 : 0);
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_INVERT,
> > + cxl_pmu_config1_get_invert(event) ? 1 : 0);
> > +
> > + /* Fixed purpose counters have next two fields RO */
> > + if (test_bit(hwc->idx, info->conf_counter_bm)) {
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_EVENT_GRP_ID_IDX_MSK,
> > + hwc->event_base);
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_EVENTS_MSK,
> > + cxl_pmu_config_get_mask(event));
> > + }
> > + cfg &= ~CXL_PMU_COUNTER_CFG_THRESHOLD_MSK;
> > + /*
> > + * For events that generate only 1 count per clock the CXL 3.0 spec
> > + * states the threshold shall be set to 1 but if set to 0 it will
> > + * count the raw value anwyay?
> > + * There is no definition of what events will count multiple per cycle
> > + * and hence to which non 1 values of threshold can apply.
> > + * (CXL 3.0 8.2.7.2.1 Counter Configuration - threshold field definition)
> > + */
> > + cfg |= FIELD_PREP(CXL_PMU_COUNTER_CFG_THRESHOLD_MSK,
> > + cxl_pmu_config1_get_threshold(event));
> > + writeq(cfg, base + CXL_PMU_COUNTER_CFG_REG(hwc->idx));
> > +
> > + local64_set(&hwc->prev_count, 0);
> > + writeq(0, base + CXL_PMU_COUNTER_REG(hwc->idx));
> > +
> > + perf_event_update_userpage(event);
> > +}
> > +
> > +static u64 cxl_pmu_read_counter(struct perf_event *event)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > + void __iomem *base = info->base;
> > +
> > + return readq(base + CXL_PMU_COUNTER_REG(event->hw.idx));
> > +}
> > +
> > +static void __cxl_pmu_read(struct perf_event *event, bool overflow)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > + struct hw_perf_event *hwc = &event->hw;
> > + u64 new_cnt, prev_cnt, delta;
> > +
> > + do {
> > + prev_cnt = local64_read(&hwc->prev_count);
> > + new_cnt = cxl_pmu_read_counter(event);
> > + } while (local64_cmpxchg(&hwc->prev_count, prev_cnt, new_cnt) != prev_cnt);
> > +
> > + /*
> > + * If we know an overflow occur then take that into account.
> > + * Note counter is not reset as that would lose events
> > + */
> > + delta = (new_cnt - prev_cnt) & GENMASK_ULL(info->counter_width - 1, 0);
> > + if (overflow && delta < GENMASK_ULL(info->counter_width - 1, 0))
> > + delta += (1UL << info->counter_width);
> > +
> > + local64_add(delta, &event->count);
> > +}
> > +
> > +static void cxl_pmu_read(struct perf_event *event)
> > +{
> > + __cxl_pmu_read(event, false);
> > +}
> > +
> > +static void cxl_pmu_event_stop(struct perf_event *event, int flags)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > + void __iomem *base = info->base;
> > + struct hw_perf_event *hwc = &event->hw;
> > + u64 cfg;
> > +
> > + cxl_pmu_read(event);
> > + WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
> > + hwc->state |= PERF_HES_STOPPED;
> > +
> > + cfg = readq(base + CXL_PMU_COUNTER_CFG_REG(hwc->idx));
> > + cfg &= ~(FIELD_PREP(CXL_PMU_COUNTER_CFG_INT_ON_OVRFLW, 1) |
> > + FIELD_PREP(CXL_PMU_COUNTER_CFG_ENABLE, 1));
> > + writeq(cfg, base + CXL_PMU_COUNTER_CFG_REG(hwc->idx));
> > +
> > + hwc->state |= PERF_HES_UPTODATE;
> > +}
> > +
> > +static int cxl_pmu_event_add(struct perf_event *event, int flags)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > + struct hw_perf_event *hwc = &event->hw;
> > + int idx, rc;
> > + int event_idx = 0;
> > +
> > + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> > +
> > + rc = cxl_pmu_get_event_idx(event, &idx, &event_idx);
> > + if (rc < 0)
> > + return rc;
> > +
> > + hwc->idx = idx;
> > +
> > + /* Only set for configurable counters */
> > + hwc->event_base = event_idx;
> > + info->hw_events[idx] = event;
> > + set_bit(idx, info->used_counter_bm);
> > +
> > + if (flags & PERF_EF_START)
> > + cxl_pmu_event_start(event, PERF_EF_RELOAD);
> > +
> > + return 0;
> > +}
> > +
> > +static void cxl_pmu_event_del(struct perf_event *event, int flags)
> > +{
> > + struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + cxl_pmu_event_stop(event, PERF_EF_UPDATE);
> > + clear_bit(hwc->idx, info->used_counter_bm);
> > + info->hw_events[hwc->idx] = NULL;
> > + perf_event_update_userpage(event);
> > +}
> > +
> > +static irqreturn_t cxl_pmu_irq(int irq, void *data)
> > +{
> > + struct cxl_pmu_info *info = data;
> > + void __iomem *base = info->base;
> > + u64 overflowed;
> > + DECLARE_BITMAP(overflowedbm, 64);
> > + int i;
> > +
> > + overflowed = readq(base + CXL_PMU_OVERFLOW_REG);
> > +
> > + /* Interrupt may be shared, so maybe it isn't ours */
> > + if (!overflowed)
> > + return IRQ_NONE;
> > +
> > + bitmap_from_arr64(overflowedbm, &overflowed, 64);
> > + for_each_set_bit(i, overflowedbm, info->num_counters) {
> > + struct perf_event *event = info->hw_events[i];
> > +
> > + if (!event) {
> > + dev_dbg(info->pmu.dev,
> > + "overflow but on non enabled counter %d\n", i);
> > + continue;
> > + }
> > +
> > + __cxl_pmu_read(event, true);
> > + }
> > +
> > + writeq(overflowed, base + CXL_PMU_OVERFLOW_REG);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static void cxl_pmu_perf_unregister(void *_info)
> > +{
> > + struct cxl_pmu_info *info = _info;
> > +
> > + perf_pmu_unregister(&info->pmu);
> > +}
> > +
> > +static void cxl_pmu_cpuhp_remove(void *_info)
> > +{
> > + struct cxl_pmu_info *info = _info;
> > +
> > + cpuhp_state_remove_instance_nocalls(cxl_pmu_cpuhp_state_num, &info->node);
> > +}
> > +
> > +static int cxl_pmu_probe(struct device *dev)
> > +{
> > + struct cxl_pmu *pmu = to_cxl_pmu(dev);
> > + struct pci_dev *pdev = to_pci_dev(dev->parent);
> > + struct cxl_pmu_info *info;
> > + char *irq_name;
> > + char *dev_name;
> > + int rc, irq;
> > +
> > + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> > + if (!info)
> > + return -ENOMEM;
> > +
> > + dev_set_drvdata(dev, info);
> > + INIT_LIST_HEAD(&info->event_caps_fixed);
> > + INIT_LIST_HEAD(&info->event_caps_configurable);
> > +
> > + info->base = pmu->base;
> > +
> > + info->on_cpu = -1;
> > + rc = cxl_pmu_parse_caps(dev, info);
> > + if (rc)
> > + return rc;
> > +
> > + info->hw_events = devm_kcalloc(dev, sizeof(*info->hw_events),
> > + info->num_counters, GFP_KERNEL);
> > + if (!info->hw_events)
> > + return -ENOMEM;
> > +
> > + switch (pmu->type) {
> > + case CXL_PMU_MEMDEV:
> > + dev_name = devm_kasprintf(dev, GFP_KERNEL, "cxl_pmu_mem%d.%d",
> > + pmu->assoc_id, pmu->index);
> > + break;
> > + }
> > + if (!dev_name)
> > + return -ENOMEM;
> > +
> > + info->pmu = (struct pmu) {
> > + .name = dev_name,
> > + .parent = dev,
> > + .module = THIS_MODULE,
> > + .event_init = cxl_pmu_event_init,
> > + .pmu_enable = cxl_pmu_enable,
> > + .pmu_disable = cxl_pmu_disable,
> > + .add = cxl_pmu_event_add,
> > + .del = cxl_pmu_event_del,
> > + .start = cxl_pmu_event_start,
> > + .stop = cxl_pmu_event_stop,
> > + .read = cxl_pmu_read,
> > + .task_ctx_nr = perf_invalid_context,
> > + .attr_groups = cxl_pmu_attr_groups,
> > + .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
> > + };
> > +
> > + if (info->irq <= 0)
> > + return -EINVAL;
> > +
> > + rc = pci_irq_vector(pdev, info->irq);
> > + if (rc < 0)
> > + return rc;
> > + irq = rc;
> > +
> > + irq_name = devm_kasprintf(dev, GFP_KERNEL, "%s_overflow\n", dev_name);
> > + if (!irq_name)
> > + return -ENOMEM;
> > +
> > + rc = devm_request_irq(dev, irq, cxl_pmu_irq, IRQF_SHARED | IRQF_ONESHOT,
> > + irq_name, info);
> > + if (rc)
> > + return rc;
> > + info->irq = irq;
> > +
> > + rc = cpuhp_state_add_instance(cxl_pmu_cpuhp_state_num, &info->node);
> > + if (rc)
> > + return rc;
> > +
> > + rc = devm_add_action_or_reset(dev, cxl_pmu_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_pmu_perf_unregister, info);
> > + if (rc)
> > + return rc;
> > +
> > + return 0;
> > +}
> > +
> > +static struct cxl_driver cxl_pmu_driver = {
> > + .name = "cxl_pmu",
> > + .probe = cxl_pmu_probe,
> > + .id = CXL_DEVICE_PMU,
> > +};
> > +
> > +static int cxl_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)
> > +{
> > + struct cxl_pmu_info *info = hlist_entry_safe(node, struct cxl_pmu_info, node);
> > +
> > + if (info->on_cpu != -1)
> > + return 0;
> > +
> > + info->on_cpu = cpu;
> > + /*
> > + * CPU HP lock is held so we should be guaranteed that the CPU hasn't yet
> > + * gone away again.
> > + */
> > + WARN_ON(irq_set_affinity(info->irq, cpumask_of(cpu)));
> > +
> > + return 0;
> > +}
> > +
> > +static int cxl_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
> > +{
> > + struct cxl_pmu_info *info = hlist_entry_safe(node, struct cxl_pmu_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_pmu_init(void)
> > +{
> > + int rc;
> > +
> > + rc = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
> > + "AP_PERF_CXL_PMU_ONLINE",
> > + cxl_pmu_online_cpu, cxl_pmu_offline_cpu);
> > + if (rc < 0)
> > + return rc;
> > + cxl_pmu_cpuhp_state_num = rc;
> > +
> > + rc = cxl_driver_register(&cxl_pmu_driver);
> > + if (rc)
> > + cpuhp_remove_multi_state(cxl_pmu_cpuhp_state_num);
> > +
> > + return rc;
> > +}
> > +
> > +static __exit void cxl_pmu_exit(void)
> > +{
> > + cxl_driver_unregister(&cxl_pmu_driver);
> > + cpuhp_remove_multi_state(cxl_pmu_cpuhp_state_num);
> > +}
> > +
> > +MODULE_LICENSE("GPL");
> > +MODULE_IMPORT_NS(CXL);
> > +module_init(cxl_pmu_init);
> > +module_exit(cxl_pmu_exit);
> > +MODULE_ALIAS_CXL(CXL_DEVICE_PMU);
> > --
> > 2.37.2
> >
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