Perf events changes for v6.5:

- Rework & fix the event forwarding logic by extending the
   core interface. This fixes AMD PMU events that have to
   be forwarded from the core PMU to the IBS PMU.
 
 - Add self-tests to test AMD IBS invocation via core PMU events
 
 - Clean up Intel FixCntrCtl MSR encoding & handling
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf events updates from Ingo Molnar:

 - Rework & fix the event forwarding logic by extending the core
   interface.

   This fixes AMD PMU events that have to be forwarded from the
   core PMU to the IBS PMU.

 - Add self-tests to test AMD IBS invocation via core PMU events

 - Clean up Intel FixCntrCtl MSR encoding & handling

* tag 'perf-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Re-instate the linear PMU search
  perf/x86/intel: Define bit macros for FixCntrCtl MSR
  perf test: Add selftest to test IBS invocation via core pmu events
  perf/core: Remove pmu linear searching code
  perf/ibs: Fix interface via core pmu events
  perf/core: Rework forwarding of {task|cpu}-clock events

arch/x86/events/amd/core.c

@@ -374,7 +374,7 @@ static int amd_pmu_hw_config(struct perf_event *event)
 
 	/* pass precise event sampling to ibs: */
 	if (event->attr.precise_ip && get_ibs_caps())
-		return -ENOENT;
+		return forward_event_to_ibs(event);
 
 	if (has_branch_stack(event) && !x86_pmu.lbr_nr)
 		return -EOPNOTSUPP;

arch/x86/events/amd/ibs.c

@@ -190,7 +190,7 @@ static struct perf_ibs *get_ibs_pmu(int type)
 }
 
 /*
- * Use IBS for precise event sampling:
+ * core pmu config -> IBS config
  *
  *  perf record -a -e cpu-cycles:p ...    # use ibs op counting cycle count
  *  perf record -a -e r076:p ...          # same as -e cpu-cycles:p
@@ -199,25 +199,9 @@ static struct perf_ibs *get_ibs_pmu(int type)
  * IbsOpCntCtl (bit 19) of IBS Execution Control Register (IbsOpCtl,
  * MSRC001_1033) is used to select either cycle or micro-ops counting
  * mode.
- *
- * The rip of IBS samples has skid 0. Thus, IBS supports precise
- * levels 1 and 2 and the PERF_EFLAGS_EXACT is set. In rare cases the
- * rip is invalid when IBS was not able to record the rip correctly.
- * We clear PERF_EFLAGS_EXACT and take the rip from pt_regs then.
- *
  */
-static int perf_ibs_precise_event(struct perf_event *event, u64 *config)
+static int core_pmu_ibs_config(struct perf_event *event, u64 *config)
 {
-	switch (event->attr.precise_ip) {
-	case 0:
-		return -ENOENT;
-	case 1:
-	case 2:
-		break;
-	default:
-		return -EOPNOTSUPP;
-	}
-
 	switch (event->attr.type) {
 	case PERF_TYPE_HARDWARE:
 		switch (event->attr.config) {
@@ -243,22 +227,37 @@ static int perf_ibs_precise_event(struct perf_event *event, u64 *config)
 	return -EOPNOTSUPP;
 }
 
+/*
+ * The rip of IBS samples has skid 0. Thus, IBS supports precise
+ * levels 1 and 2 and the PERF_EFLAGS_EXACT is set. In rare cases the
+ * rip is invalid when IBS was not able to record the rip correctly.
+ * We clear PERF_EFLAGS_EXACT and take the rip from pt_regs then.
+ */
+int forward_event_to_ibs(struct perf_event *event)
+{
+	u64 config = 0;
+
+	if (!event->attr.precise_ip || event->attr.precise_ip > 2)
+		return -EOPNOTSUPP;
+
+	if (!core_pmu_ibs_config(event, &config)) {
+		event->attr.type = perf_ibs_op.pmu.type;
+		event->attr.config = config;
+	}
+	return -ENOENT;
+}
+
 static int perf_ibs_init(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;
 	struct perf_ibs *perf_ibs;
 	u64 max_cnt, config;
-	int ret;
 
 	perf_ibs = get_ibs_pmu(event->attr.type);
-	if (perf_ibs) {
-		config = event->attr.config;
-	} else {
-		perf_ibs = &perf_ibs_op;
-		ret = perf_ibs_precise_event(event, &config);
-		if (ret)
-			return ret;
-	}
+	if (!perf_ibs)
+		return -ENOENT;
+
+	config = event->attr.config;
 
 	if (event->pmu != &perf_ibs->pmu)
 		return -ENOENT;

arch/x86/events/intel/core.c

@@ -2461,7 +2461,7 @@ static void intel_pmu_disable_fixed(struct perf_event *event)
 
 	intel_clear_masks(event, idx);
 
-	mask = 0xfULL << ((idx - INTEL_PMC_IDX_FIXED) * 4);
+	mask = intel_fixed_bits_by_idx(idx - INTEL_PMC_IDX_FIXED, INTEL_FIXED_BITS_MASK);
 	cpuc->fixed_ctrl_val &= ~mask;
 }
 
@@ -2760,25 +2760,25 @@ static void intel_pmu_enable_fixed(struct perf_event *event)
 	 * if requested:
 	 */
 	if (!event->attr.precise_ip)
-		bits |= 0x8;
+		bits |= INTEL_FIXED_0_ENABLE_PMI;
 	if (hwc->config & ARCH_PERFMON_EVENTSEL_USR)
-		bits |= 0x2;
+		bits |= INTEL_FIXED_0_USER;
 	if (hwc->config & ARCH_PERFMON_EVENTSEL_OS)
-		bits |= 0x1;
+		bits |= INTEL_FIXED_0_KERNEL;
 
 	/*
 	 * ANY bit is supported in v3 and up
 	 */
 	if (x86_pmu.version > 2 && hwc->config & ARCH_PERFMON_EVENTSEL_ANY)
-		bits |= 0x4;
+		bits |= INTEL_FIXED_0_ANYTHREAD;
 
 	idx -= INTEL_PMC_IDX_FIXED;
-	bits <<= (idx * 4);
-	mask = 0xfULL << (idx * 4);
+	bits = intel_fixed_bits_by_idx(idx, bits);
+	mask = intel_fixed_bits_by_idx(idx, INTEL_FIXED_BITS_MASK);
 
 	if (x86_pmu.intel_cap.pebs_baseline && event->attr.precise_ip) {
-		bits |= ICL_FIXED_0_ADAPTIVE << (idx * 4);
-		mask |= ICL_FIXED_0_ADAPTIVE << (idx * 4);
+		bits |= intel_fixed_bits_by_idx(idx, ICL_FIXED_0_ADAPTIVE);
+		mask |= intel_fixed_bits_by_idx(idx, ICL_FIXED_0_ADAPTIVE);
 	}
 
 	cpuc->fixed_ctrl_val &= ~mask;

arch/x86/include/asm/perf_event.h

@@ -32,11 +32,21 @@
 #define ARCH_PERFMON_EVENTSEL_INV			(1ULL << 23)
 #define ARCH_PERFMON_EVENTSEL_CMASK			0xFF000000ULL
 
+#define INTEL_FIXED_BITS_MASK				0xFULL
+#define INTEL_FIXED_BITS_STRIDE			4
+#define INTEL_FIXED_0_KERNEL				(1ULL << 0)
+#define INTEL_FIXED_0_USER				(1ULL << 1)
+#define INTEL_FIXED_0_ANYTHREAD			(1ULL << 2)
+#define INTEL_FIXED_0_ENABLE_PMI			(1ULL << 3)
+
 #define HSW_IN_TX					(1ULL << 32)
 #define HSW_IN_TX_CHECKPOINTED				(1ULL << 33)
 #define ICL_EVENTSEL_ADAPTIVE				(1ULL << 34)
 #define ICL_FIXED_0_ADAPTIVE				(1ULL << 32)
 
+#define intel_fixed_bits_by_idx(_idx, _bits)			\
+	((_bits) << ((_idx) * INTEL_FIXED_BITS_STRIDE))
+
 #define AMD64_EVENTSEL_INT_CORE_ENABLE			(1ULL << 36)
 #define AMD64_EVENTSEL_GUESTONLY			(1ULL << 40)
 #define AMD64_EVENTSEL_HOSTONLY				(1ULL << 41)
@@ -478,8 +488,10 @@ struct pebs_xmm {
 
 #ifdef CONFIG_X86_LOCAL_APIC
 extern u32 get_ibs_caps(void);
+extern int forward_event_to_ibs(struct perf_event *event);
 #else
 static inline u32 get_ibs_caps(void) { return 0; }
+static inline int forward_event_to_ibs(struct perf_event *event) { return -ENOENT; }
 #endif
 
 #ifdef CONFIG_PERF_EVENTS

include/linux/perf_event.h

@@ -295,6 +295,8 @@ struct perf_event_pmu_context;
 
 struct perf_output_handle;
 
+#define PMU_NULL_DEV	((void *)(~0UL))
+
 /**
  * struct pmu - generic performance monitoring unit
  */
@@ -827,6 +829,14 @@ struct perf_event {
 	void *security;
 #endif
 	struct list_head		sb_list;
+
+	/*
+	 * Certain events gets forwarded to another pmu internally by over-
+	 * writing kernel copy of event->attr.type without user being aware
+	 * of it. event->orig_type contains original 'type' requested by
+	 * user.
+	 */
+	__u32				orig_type;
 #endif /* CONFIG_PERF_EVENTS */
 };
 

kernel/events/core.c

@@ -6647,7 +6647,7 @@ static void perf_sigtrap(struct perf_event *event)
 		return;
 
 	send_sig_perf((void __user *)event->pending_addr,
-		      event->attr.type, event->attr.sig_data);
+		      event->orig_type, event->attr.sig_data);
 }
 
 /*
@@ -9951,6 +9951,9 @@ static void sw_perf_event_destroy(struct perf_event *event)
 	swevent_hlist_put();
 }
 
+static struct pmu perf_cpu_clock; /* fwd declaration */
+static struct pmu perf_task_clock;
+
 static int perf_swevent_init(struct perf_event *event)
 {
 	u64 event_id = event->attr.config;
@@ -9966,7 +9969,10 @@ static int perf_swevent_init(struct perf_event *event)
 
 	switch (event_id) {
 	case PERF_COUNT_SW_CPU_CLOCK:
+		event->attr.type = perf_cpu_clock.type;
+		return -ENOENT;
 	case PERF_COUNT_SW_TASK_CLOCK:
+		event->attr.type = perf_task_clock.type;
 		return -ENOENT;
 
 	default:
@@ -11098,7 +11104,7 @@ static void cpu_clock_event_read(struct perf_event *event)
 
 static int cpu_clock_event_init(struct perf_event *event)
 {
-	if (event->attr.type != PERF_TYPE_SOFTWARE)
+	if (event->attr.type != perf_cpu_clock.type)
 		return -ENOENT;
 
 	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
@@ -11119,6 +11125,7 @@ static struct pmu perf_cpu_clock = {
 	.task_ctx_nr	= perf_sw_context,
 
 	.capabilities	= PERF_PMU_CAP_NO_NMI,
+	.dev		= PMU_NULL_DEV,
 
 	.event_init	= cpu_clock_event_init,
 	.add		= cpu_clock_event_add,
@@ -11179,7 +11186,7 @@ static void task_clock_event_read(struct perf_event *event)
 
 static int task_clock_event_init(struct perf_event *event)
 {
-	if (event->attr.type != PERF_TYPE_SOFTWARE)
+	if (event->attr.type != perf_task_clock.type)
 		return -ENOENT;
 
 	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
@@ -11200,6 +11207,7 @@ static struct pmu perf_task_clock = {
 	.task_ctx_nr	= perf_sw_context,
 
 	.capabilities	= PERF_PMU_CAP_NO_NMI,
+	.dev		= PMU_NULL_DEV,
 
 	.event_init	= task_clock_event_init,
 	.add		= task_clock_event_add,
@@ -11427,31 +11435,31 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type)
 		goto unlock;
 
 	pmu->type = -1;
-	if (!name)
-		goto skip_type;
+	if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) {
+		ret = -EINVAL;
+		goto free_pdc;
+	}
+
 	pmu->name = name;
 
-	if (type != PERF_TYPE_SOFTWARE) {
-		if (type >= 0)
-			max = type;
+	if (type >= 0)
+		max = type;
 
-		ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
-		if (ret < 0)
-			goto free_pdc;
+	ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto free_pdc;
 
-		WARN_ON(type >= 0 && ret != type);
+	WARN_ON(type >= 0 && ret != type);
 
-		type = ret;
-	}
+	type = ret;
 	pmu->type = type;
 
-	if (pmu_bus_running) {
+	if (pmu_bus_running && !pmu->dev) {
 		ret = pmu_dev_alloc(pmu);
 		if (ret)
 			goto free_idr;
 	}
 
-skip_type:
 	ret = -ENOMEM;
 	pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
 	if (!pmu->cpu_pmu_context)
@@ -11493,16 +11501,7 @@ skip_type:
 	if (!pmu->event_idx)
 		pmu->event_idx = perf_event_idx_default;
 
-	/*
-	 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
-	 * since these cannot be in the IDR. This way the linear search
-	 * is fast, provided a valid software event is provided.
-	 */
-	if (type == PERF_TYPE_SOFTWARE || !name)
-		list_add_rcu(&pmu->entry, &pmus);
-	else
-		list_add_tail_rcu(&pmu->entry, &pmus);
-
+	list_add_rcu(&pmu->entry, &pmus);
 	atomic_set(&pmu->exclusive_cnt, 0);
 	ret = 0;
 unlock:
@@ -11511,12 +11510,13 @@ unlock:
 	return ret;
 
 free_dev:
-	device_del(pmu->dev);
-	put_device(pmu->dev);
+	if (pmu->dev && pmu->dev != PMU_NULL_DEV) {
+		device_del(pmu->dev);
+		put_device(pmu->dev);
+	}
 
 free_idr:
-	if (pmu->type != PERF_TYPE_SOFTWARE)
-		idr_remove(&pmu_idr, pmu->type);
+	idr_remove(&pmu_idr, pmu->type);
 
 free_pdc:
 	free_percpu(pmu->pmu_disable_count);
@@ -11537,9 +11537,8 @@ void perf_pmu_unregister(struct pmu *pmu)
 	synchronize_rcu();
 
 	free_percpu(pmu->pmu_disable_count);
-	if (pmu->type != PERF_TYPE_SOFTWARE)
-		idr_remove(&pmu_idr, pmu->type);
-	if (pmu_bus_running) {
+	idr_remove(&pmu_idr, pmu->type);
+	if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
 		if (pmu->nr_addr_filters)
 			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
 		device_del(pmu->dev);
@@ -11613,6 +11612,12 @@ static struct pmu *perf_init_event(struct perf_event *event)
 
 	idx = srcu_read_lock(&pmus_srcu);
 
+	/*
+	 * Save original type before calling pmu->event_init() since certain
+	 * pmus overwrites event->attr.type to forward event to another pmu.
+	 */
+	event->orig_type = event->attr.type;
+
 	/* Try parent's PMU first: */
 	if (event->parent && event->parent->pmu) {
 		pmu = event->parent->pmu;
@@ -13652,8 +13657,8 @@ void __init perf_event_init(void)
 	perf_event_init_all_cpus();
 	init_srcu_struct(&pmus_srcu);
 	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
-	perf_pmu_register(&perf_cpu_clock, NULL, -1);
-	perf_pmu_register(&perf_task_clock, NULL, -1);
+	perf_pmu_register(&perf_cpu_clock, "cpu_clock", -1);
+	perf_pmu_register(&perf_task_clock, "task_clock", -1);
 	perf_tp_register();
 	perf_event_init_cpu(smp_processor_id());
 	register_reboot_notifier(&perf_reboot_notifier);
@@ -13696,7 +13701,7 @@ static int __init perf_event_sysfs_init(void)
 		goto unlock;
 
 	list_for_each_entry(pmu, &pmus, entry) {
-		if (!pmu->name || pmu->type < 0)
+		if (pmu->dev)
 			continue;
 
 		ret = pmu_dev_alloc(pmu);

tools/perf/arch/x86/include/arch-tests.h

@@ -11,6 +11,7 @@ int test__intel_pt_pkt_decoder(struct test_suite *test, int subtest);
 int test__intel_pt_hybrid_compat(struct test_suite *test, int subtest);
 int test__bp_modify(struct test_suite *test, int subtest);
 int test__x86_sample_parsing(struct test_suite *test, int subtest);
+int test__amd_ibs_via_core_pmu(struct test_suite *test, int subtest);
 
 extern struct test_suite *arch_tests[];
 

tools/perf/arch/x86/tests/Build

@@ -5,3 +5,4 @@ perf-y += arch-tests.o
 perf-y += sample-parsing.o
 perf-$(CONFIG_AUXTRACE) += insn-x86.o intel-pt-test.o
 perf-$(CONFIG_X86_64) += bp-modify.o
+perf-y += amd-ibs-via-core-pmu.o

tools/perf/arch/x86/tests/amd-ibs-via-core-pmu.c

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "arch-tests.h"
+#include "linux/perf_event.h"
+#include "tests/tests.h"
+#include "pmu.h"
+#include "pmus.h"
+#include "../perf-sys.h"
+#include "debug.h"
+
+#define NR_SUB_TESTS 5
+
+static struct sub_tests {
+	int type;
+	unsigned long config;
+	bool valid;
+} sub_tests[NR_SUB_TESTS] = {
+	{ PERF_TYPE_HARDWARE, PERF_COUNT_HW_CPU_CYCLES, true },
+	{ PERF_TYPE_HARDWARE, PERF_COUNT_HW_INSTRUCTIONS, false },
+	{ PERF_TYPE_RAW, 0x076, true },
+	{ PERF_TYPE_RAW, 0x0C1, true },
+	{ PERF_TYPE_RAW, 0x012, false },
+};
+
+static int event_open(int type, unsigned long config)
+{
+	struct perf_event_attr attr;
+
+	memset(&attr, 0, sizeof(struct perf_event_attr));
+	attr.type = type;
+	attr.size = sizeof(struct perf_event_attr);
+	attr.config = config;
+	attr.disabled = 1;
+	attr.precise_ip = 1;
+	attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
+	attr.sample_period = 100000;
+
+	return sys_perf_event_open(&attr, -1, 0, -1, 0);
+}
+
+int test__amd_ibs_via_core_pmu(struct test_suite *test __maybe_unused,
+			       int subtest __maybe_unused)
+{
+	struct perf_pmu *ibs_pmu;
+	int ret = TEST_OK;
+	int fd, i;
+
+	if (list_empty(&pmus))
+		perf_pmu__scan(NULL);
+
+	ibs_pmu = perf_pmu__find("ibs_op");
+	if (!ibs_pmu)
+		return TEST_SKIP;
+
+	for (i = 0; i < NR_SUB_TESTS; i++) {
+		fd = event_open(sub_tests[i].type, sub_tests[i].config);
+		pr_debug("type: 0x%x, config: 0x%lx, fd: %d  -  ", sub_tests[i].type,
+			 sub_tests[i].config, fd);
+		if ((sub_tests[i].valid && fd == -1) ||
+		    (!sub_tests[i].valid && fd > 0)) {
+			pr_debug("Fail\n");
+			ret = TEST_FAIL;
+		} else {
+			pr_debug("Pass\n");
+		}
+
+		if (fd > 0)
+			close(fd);
+	}
+
+	return ret;
+}

tools/perf/arch/x86/tests/arch-tests.c

@@ -22,6 +22,7 @@ struct test_suite suite__intel_pt = {
 DEFINE_SUITE("x86 bp modify", bp_modify);
 #endif
 DEFINE_SUITE("x86 Sample parsing", x86_sample_parsing);
+DEFINE_SUITE("AMD IBS via core pmu", amd_ibs_via_core_pmu);
 
 struct test_suite *arch_tests[] = {
 #ifdef HAVE_DWARF_UNWIND_SUPPORT
@@ -35,5 +36,6 @@ struct test_suite *arch_tests[] = {
 	&suite__bp_modify,
 #endif
 	&suite__x86_sample_parsing,
+	&suite__amd_ibs_via_core_pmu,
 	NULL,
 };