1 files changed, 409 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c
new file mode 100644
index 000000000000..89b8b619d5d5
--- /dev/null
+++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Resource Director Technology(RDT)
+ * - Intel Application Energy Telemetry
+ *
+ * Copyright (C) 2025 Intel Corporation
+ *
+ * Author:
+ *    Tony Luck <tony.luck@intel.com>
+ */
+
+#define pr_fmt(fmt)   "resctrl: " fmt
+
+#include <linux/bits.h>
+#include <linux/compiler_types.h>
+#include <linux/container_of.h>
+#include <linux/cpumask.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/gfp_types.h>
+#include <linux/init.h>
+#include <linux/intel_pmt_features.h>
+#include <linux/intel_vsec.h>
+#include <linux/io.h>
+#include <linux/minmax.h>
+#include <linux/printk.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/resctrl.h>
+#include <linux/resctrl_types.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/topology.h>
+#include <linux/types.h>
+
+#include "internal.h"
+
+/**
+ * struct pmt_event - Telemetry event.
+ * @id:		Resctrl event id.
+ * @idx:	Counter index within each per-RMID block of counters.
+ * @bin_bits:	Zero for integer valued events, else number bits in fraction
+ *		part of fixed-point.
+ */
+struct pmt_event {
+	enum resctrl_event_id	id;
+	unsigned int		idx;
+	unsigned int		bin_bits;
+};
+
+#define EVT(_id, _idx, _bits) { .id = _id, .idx = _idx, .bin_bits = _bits }
+
+/**
+ * struct event_group - Events with the same feature type ("energy" or "perf") and GUID.
+ * @pfname:		PMT feature name ("energy" or "perf") of this event group.
+ *			Used by boot rdt= option.
+ * @pfg:		Points to the aggregated telemetry space information
+ *			returned by the intel_pmt_get_regions_by_feature()
+ *			call to the INTEL_PMT_TELEMETRY driver that contains
+ *			data for all telemetry regions of type @pfname.
+ *			Valid if the system supports the event group,
+ *			NULL otherwise.
+ * @force_off:		True when "rdt" command line or architecture code disables
+ *			this event group due to insufficient RMIDs.
+ * @force_on:		True when "rdt" command line overrides disable of this
+ *			event group.
+ * @guid:		Unique number per XML description file.
+ * @num_rmid:		Number of RMIDs supported by this group. May be
+ *			adjusted downwards if enumeration from
+ *			intel_pmt_get_regions_by_feature() indicates fewer
+ *			RMIDs can be tracked simultaneously.
+ * @mmio_size:		Number of bytes of MMIO registers for this group.
+ * @num_events:		Number of events in this group.
+ * @evts:		Array of event descriptors.
+ */
+struct event_group {
+	/* Data fields for additional structures to manage this group. */
+	const char			*pfname;
+	struct pmt_feature_group	*pfg;
+	bool				force_off, force_on;
+
+	/* Remaining fields initialized from XML file. */
+	u32				guid;
+	u32				num_rmid;
+	size_t				mmio_size;
+	unsigned int			num_events;
+	struct pmt_event		evts[] __counted_by(num_events);
+};
+
+#define XML_MMIO_SIZE(num_rmids, num_events, num_extra_status) \
+		      (((num_rmids) * (num_events) + (num_extra_status)) * sizeof(u64))
+
+/*
+ * Link: https://github.com/intel/Intel-PMT/blob/main/xml/CWF/OOBMSM/RMID-ENERGY/cwf_aggregator.xml
+ */
+static struct event_group energy_0x26696143 = {
+	.pfname		= "energy",
+	.guid		= 0x26696143,
+	.num_rmid	= 576,
+	.mmio_size	= XML_MMIO_SIZE(576, 2, 3),
+	.num_events	= 2,
+	.evts		= {
+		EVT(PMT_EVENT_ENERGY, 0, 18),
+		EVT(PMT_EVENT_ACTIVITY, 1, 18),
+	}
+};
+
+/*
+ * Link: https://github.com/intel/Intel-PMT/blob/main/xml/CWF/OOBMSM/RMID-PERF/cwf_aggregator.xml
+ */
+static struct event_group perf_0x26557651 = {
+	.pfname		= "perf",
+	.guid		= 0x26557651,
+	.num_rmid	= 576,
+	.mmio_size	= XML_MMIO_SIZE(576, 7, 3),
+	.num_events	= 7,
+	.evts		= {
+		EVT(PMT_EVENT_STALLS_LLC_HIT, 0, 0),
+		EVT(PMT_EVENT_C1_RES, 1, 0),
+		EVT(PMT_EVENT_UNHALTED_CORE_CYCLES, 2, 0),
+		EVT(PMT_EVENT_STALLS_LLC_MISS, 3, 0),
+		EVT(PMT_EVENT_AUTO_C6_RES, 4, 0),
+		EVT(PMT_EVENT_UNHALTED_REF_CYCLES, 5, 0),
+		EVT(PMT_EVENT_UOPS_RETIRED, 6, 0),
+	}
+};
+
+static struct event_group *known_event_groups[] = {
+	&energy_0x26696143,
+	&perf_0x26557651,
+};
+
+#define for_each_event_group(_peg)						\
+	for (_peg = known_event_groups;						\
+	     _peg < &known_event_groups[ARRAY_SIZE(known_event_groups)];	\
+	     _peg++)
+
+bool intel_handle_aet_option(bool force_off, char *tok)
+{
+	struct event_group **peg;
+	bool ret = false;
+	u32 guid = 0;
+	char *name;
+
+	if (!tok)
+		return false;
+
+	name = strsep(&tok, ":");
+	if (tok && kstrtou32(tok, 16, &guid))
+		return false;
+
+	for_each_event_group(peg) {
+		if (strcmp(name, (*peg)->pfname))
+			continue;
+		if (guid && (*peg)->guid != guid)
+			continue;
+		if (force_off)
+			(*peg)->force_off = true;
+		else
+			(*peg)->force_on = true;
+		ret = true;
+	}
+
+	return ret;
+}
+
+static bool skip_telem_region(struct telemetry_region *tr, struct event_group *e)
+{
+	if (tr->guid != e->guid)
+		return true;
+	if (tr->plat_info.package_id >= topology_max_packages()) {
+		pr_warn("Bad package %u in guid 0x%x\n", tr->plat_info.package_id,
+			tr->guid);
+		return true;
+	}
+	if (tr->size != e->mmio_size) {
+		pr_warn("MMIO space wrong size (%zu bytes) for guid 0x%x. Expected %zu bytes.\n",
+			tr->size, e->guid, e->mmio_size);
+		return true;
+	}
+
+	return false;
+}
+
+static bool group_has_usable_regions(struct event_group *e, struct pmt_feature_group *p)
+{
+	bool usable_regions = false;
+
+	for (int i = 0; i < p->count; i++) {
+		if (skip_telem_region(&p->regions[i], e)) {
+			/*
+			 * Clear the address field of regions that did not pass the checks in
+			 * skip_telem_region() so they will not be used by intel_aet_read_event().
+			 * This is safe to do because intel_pmt_get_regions_by_feature() allocates
+			 * a new pmt_feature_group structure to return to each caller and only makes
+			 * use of the pmt_feature_group::kref field when intel_pmt_put_feature_group()
+			 * returns the structure.
+			 */
+			p->regions[i].addr = NULL;
+
+			continue;
+		}
+		usable_regions = true;
+	}
+
+	return usable_regions;
+}
+
+static bool all_regions_have_sufficient_rmid(struct event_group *e, struct pmt_feature_group *p)
+{
+	struct telemetry_region *tr;
+
+	for (int i = 0; i < p->count; i++) {
+		if (!p->regions[i].addr)
+			continue;
+		tr = &p->regions[i];
+		if (tr->num_rmids < e->num_rmid) {
+			e->force_off = true;
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static bool enable_events(struct event_group *e, struct pmt_feature_group *p)
+{
+	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl;
+	int skipped_events = 0;
+
+	if (e->force_off)
+		return false;
+
+	if (!group_has_usable_regions(e, p))
+		return false;
+
+	/*
+	 * Only enable event group with insufficient RMIDs if the user requested
+	 * it from the kernel command line.
+	 */
+	if (!all_regions_have_sufficient_rmid(e, p) && !e->force_on) {
+		pr_info("%s %s:0x%x monitoring not enabled due to insufficient RMIDs\n",
+			r->name, e->pfname, e->guid);
+		return false;
+	}
+
+	for (int i = 0; i < p->count; i++) {
+		if (!p->regions[i].addr)
+			continue;
+		/*
+		 * e->num_rmid only adjusted lower if user (via rdt= kernel
+		 * parameter) forces an event group with insufficient RMID
+		 * to be enabled.
+		 */
+		e->num_rmid = min(e->num_rmid, p->regions[i].num_rmids);
+	}
+
+	for (int j = 0; j < e->num_events; j++) {
+		if (!resctrl_enable_mon_event(e->evts[j].id, true,
+					      e->evts[j].bin_bits, &e->evts[j]))
+			skipped_events++;
+	}
+	if (e->num_events == skipped_events) {
+		pr_info("No events enabled in %s %s:0x%x\n", r->name, e->pfname, e->guid);
+		return false;
+	}
+
+	if (r->mon.num_rmid)
+		r->mon.num_rmid = min(r->mon.num_rmid, e->num_rmid);
+	else
+		r->mon.num_rmid = e->num_rmid;
+
+	if (skipped_events)
+		pr_info("%s %s:0x%x monitoring detected (skipped %d events)\n", r->name,
+			e->pfname, e->guid, skipped_events);
+	else
+		pr_info("%s %s:0x%x monitoring detected\n", r->name, e->pfname, e->guid);
+
+	return true;
+}
+
+static enum pmt_feature_id lookup_pfid(const char *pfname)
+{
+	if (!strcmp(pfname, "energy"))
+		return FEATURE_PER_RMID_ENERGY_TELEM;
+	else if (!strcmp(pfname, "perf"))
+		return FEATURE_PER_RMID_PERF_TELEM;
+
+	pr_warn("Unknown PMT feature name '%s'\n", pfname);
+
+	return FEATURE_INVALID;
+}
+
+/*
+ * Request a copy of struct pmt_feature_group for each event group. If there is
+ * one, the returned structure has an array of telemetry_region structures,
+ * each element of the array describes one telemetry aggregator. The
+ * telemetry aggregators may have different GUIDs so obtain duplicate struct
+ * pmt_feature_group for event groups with same feature type but different
+ * GUID. Post-processing ensures an event group can only use the telemetry
+ * aggregators that match its GUID. An event group keeps a pointer to its
+ * struct pmt_feature_group to indicate that its events are successfully
+ * enabled.
+ */
+bool intel_aet_get_events(void)
+{
+	struct pmt_feature_group *p;
+	enum pmt_feature_id pfid;
+	struct event_group **peg;
+	bool ret = false;
+
+	for_each_event_group(peg) {
+		pfid = lookup_pfid((*peg)->pfname);
+		p = intel_pmt_get_regions_by_feature(pfid);
+		if (IS_ERR_OR_NULL(p))
+			continue;
+		if (enable_events(*peg, p)) {
+			(*peg)->pfg = p;
+			ret = true;
+		} else {
+			intel_pmt_put_feature_group(p);
+		}
+	}
+
+	return ret;
+}
+
+void __exit intel_aet_exit(void)
+{
+	struct event_group **peg;
+
+	for_each_event_group(peg) {
+		if ((*peg)->pfg) {
+			intel_pmt_put_feature_group((*peg)->pfg);
+			(*peg)->pfg = NULL;
+		}
+	}
+}
+
+#define DATA_VALID	BIT_ULL(63)
+#define DATA_BITS	GENMASK_ULL(62, 0)
+
+/*
+ * Read counter for an event on a domain (summing all aggregators on the
+ * domain). If an aggregator hasn't received any data for a specific RMID,
+ * the MMIO read indicates that data is not valid.  Return success if at
+ * least one aggregator has valid data.
+ */
+int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val)
+{
+	struct pmt_event *pevt = arch_priv;
+	struct event_group *e;
+	bool valid = false;
+	u64 total = 0;
+	u64 evtcount;
+	void *pevt0;
+	u32 idx;
+
+	pevt0 = pevt - pevt->idx;
+	e = container_of(pevt0, struct event_group, evts);
+	idx = rmid * e->num_events;
+	idx += pevt->idx;
+
+	if (idx * sizeof(u64) + sizeof(u64) > e->mmio_size) {
+		pr_warn_once("MMIO index %u out of range\n", idx);
+		return -EIO;
+	}
+
+	for (int i = 0; i < e->pfg->count; i++) {
+		if (!e->pfg->regions[i].addr)
+			continue;
+		if (e->pfg->regions[i].plat_info.package_id != domid)
+			continue;
+		evtcount = readq(e->pfg->regions[i].addr + idx * sizeof(u64));
+		if (!(evtcount & DATA_VALID))
+			continue;
+		total += evtcount & DATA_BITS;
+		valid = true;
+	}
+
+	if (valid)
+		*val = total;
+
+	return valid ? 0 : -EINVAL;
+}
+
+void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r,
+				struct list_head *add_pos)
+{
+	struct rdt_perf_pkg_mon_domain *d;
+	int err;
+
+	d = kzalloc_node(sizeof(*d), GFP_KERNEL, cpu_to_node(cpu));
+	if (!d)
+		return;
+
+	d->hdr.id = id;
+	d->hdr.type = RESCTRL_MON_DOMAIN;
+	d->hdr.rid = RDT_RESOURCE_PERF_PKG;
+	cpumask_set_cpu(cpu, &d->hdr.cpu_mask);
+	list_add_tail_rcu(&d->hdr.list, add_pos);
+
+	err = resctrl_online_mon_domain(r, &d->hdr);
+	if (err) {
+		list_del_rcu(&d->hdr.list);
+		synchronize_rcu();
+		kfree(d);
+	}
+}