perf/x86/intel: Process arch-PEBS records or record fragments

A significant difference with adaptive PEBS is that arch-PEBS record
supports fragments which means an arch-PEBS record could be split into
several independent fragments which have its own arch-PEBS header in
each fragment.

This patch defines architectural PEBS record layout structures and add
helpers to process arch-PEBS records or fragments. Only legacy PEBS
groups like basic, GPR, XMM and LBR groups are supported in this patch,
the new added YMM/ZMM/OPMASK vector registers capturing would be
supported in the future.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251029102136.61364-9-dapeng1.mi@linux.intel.com

arch/x86/events/intel/core.c

@@ -3215,6 +3215,19 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status)
 			status &= ~GLOBAL_STATUS_PERF_METRICS_OVF_BIT;
 	}
 
+	/*
+	 * Arch PEBS sets bit 54 in the global status register
+	 */
+	if (__test_and_clear_bit(GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT,
+				 (unsigned long *)&status)) {
+		handled++;
+		static_call(x86_pmu_drain_pebs)(regs, &data);
+
+		if (cpuc->events[INTEL_PMC_IDX_FIXED_SLOTS] &&
+		    is_pebs_counter_event_group(cpuc->events[INTEL_PMC_IDX_FIXED_SLOTS]))
+			status &= ~GLOBAL_STATUS_PERF_METRICS_OVF_BIT;
+	}
+
 	/*
 	 * Intel PT
 	 */

arch/x86/events/intel/ds.c

@@ -2270,6 +2270,117 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
 			format_group);
 }
 
+static inline bool arch_pebs_record_continued(struct arch_pebs_header *header)
+{
+	/* Continue bit or null PEBS record indicates fragment follows. */
+	return header->cont || !(header->format & GENMASK_ULL(63, 16));
+}
+
+static void setup_arch_pebs_sample_data(struct perf_event *event,
+					struct pt_regs *iregs,
+					void *__pebs,
+					struct perf_sample_data *data,
+					struct pt_regs *regs)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	u64 sample_type = event->attr.sample_type;
+	struct arch_pebs_header *header = NULL;
+	struct arch_pebs_aux *meminfo = NULL;
+	struct arch_pebs_gprs *gprs = NULL;
+	struct x86_perf_regs *perf_regs;
+	void *next_record;
+	void *at = __pebs;
+
+	if (at == NULL)
+		return;
+
+	perf_regs = container_of(regs, struct x86_perf_regs, regs);
+	perf_regs->xmm_regs = NULL;
+
+	__setup_perf_sample_data(event, iregs, data);
+
+	*regs = *iregs;
+
+again:
+	header = at;
+	next_record = at + sizeof(struct arch_pebs_header);
+	if (header->basic) {
+		struct arch_pebs_basic *basic = next_record;
+		u16 retire = 0;
+
+		next_record = basic + 1;
+
+		if (sample_type & PERF_SAMPLE_WEIGHT_STRUCT)
+			retire = basic->valid ? basic->retire : 0;
+		__setup_pebs_basic_group(event, regs, data, sample_type,
+				 basic->ip, basic->tsc, retire);
+	}
+
+	/*
+	 * The record for MEMINFO is in front of GP
+	 * But PERF_SAMPLE_TRANSACTION needs gprs->ax.
+	 * Save the pointer here but process later.
+	 */
+	if (header->aux) {
+		meminfo = next_record;
+		next_record = meminfo + 1;
+	}
+
+	if (header->gpr) {
+		gprs = next_record;
+		next_record = gprs + 1;
+
+		__setup_pebs_gpr_group(event, regs,
+				       (struct pebs_gprs *)gprs,
+				       sample_type);
+	}
+
+	if (header->aux) {
+		u64 ax = gprs ? gprs->ax : 0;
+
+		__setup_pebs_meminfo_group(event, data, sample_type,
+					   meminfo->cache_latency,
+					   meminfo->instr_latency,
+					   meminfo->address, meminfo->aux,
+					   meminfo->tsx_tuning, ax);
+	}
+
+	if (header->xmm) {
+		struct pebs_xmm *xmm;
+
+		next_record += sizeof(struct arch_pebs_xer_header);
+
+		xmm = next_record;
+		perf_regs->xmm_regs = xmm->xmm;
+		next_record = xmm + 1;
+	}
+
+	if (header->lbr) {
+		struct arch_pebs_lbr_header *lbr_header = next_record;
+		struct lbr_entry *lbr;
+		int num_lbr;
+
+		next_record = lbr_header + 1;
+		lbr = next_record;
+
+		num_lbr = header->lbr == ARCH_PEBS_LBR_NUM_VAR ?
+				lbr_header->depth :
+				header->lbr * ARCH_PEBS_BASE_LBR_ENTRIES;
+		next_record += num_lbr * sizeof(struct lbr_entry);
+
+		if (has_branch_stack(event)) {
+			intel_pmu_store_pebs_lbrs(lbr);
+			intel_pmu_lbr_save_brstack(data, cpuc, event);
+		}
+	}
+
+	/* Parse followed fragments if there are. */
+	if (arch_pebs_record_continued(header)) {
+		at = at + header->size;
+		goto again;
+	}
+}
+
 static inline void *
 get_next_pebs_record_by_bit(void *base, void *top, int bit)
 {
@@ -2753,6 +2864,78 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
 					    setup_pebs_adaptive_sample_data);
 }
 
+static void intel_pmu_drain_arch_pebs(struct pt_regs *iregs,
+				      struct perf_sample_data *data)
+{
+	short counts[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {};
+	void *last[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS];
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	union arch_pebs_index index;
+	struct x86_perf_regs perf_regs;
+	struct pt_regs *regs = &perf_regs.regs;
+	void *base, *at, *top;
+	u64 mask;
+
+	rdmsrq(MSR_IA32_PEBS_INDEX, index.whole);
+
+	if (unlikely(!index.wr)) {
+		intel_pmu_pebs_event_update_no_drain(cpuc, X86_PMC_IDX_MAX);
+		return;
+	}
+
+	base = cpuc->ds_pebs_vaddr;
+	top = (void *)((u64)cpuc->ds_pebs_vaddr +
+		       (index.wr << ARCH_PEBS_INDEX_WR_SHIFT));
+
+	index.wr = 0;
+	index.full = 0;
+	wrmsrq(MSR_IA32_PEBS_INDEX, index.whole);
+
+	mask = hybrid(cpuc->pmu, arch_pebs_cap).counters & cpuc->pebs_enabled;
+
+	if (!iregs)
+		iregs = &dummy_iregs;
+
+	/* Process all but the last event for each counter. */
+	for (at = base; at < top;) {
+		struct arch_pebs_header *header;
+		struct arch_pebs_basic *basic;
+		u64 pebs_status;
+
+		header = at;
+
+		if (WARN_ON_ONCE(!header->size))
+			break;
+
+		/* 1st fragment or single record must have basic group */
+		if (!header->basic) {
+			at += header->size;
+			continue;
+		}
+
+		basic = at + sizeof(struct arch_pebs_header);
+		pebs_status = mask & basic->applicable_counters;
+		__intel_pmu_handle_pebs_record(iregs, regs, data, at,
+					       pebs_status, counts, last,
+					       setup_arch_pebs_sample_data);
+
+		/* Skip non-last fragments */
+		while (arch_pebs_record_continued(header)) {
+			if (!header->size)
+				break;
+			at += header->size;
+			header = at;
+		}
+
+		/* Skip last fragment or the single record */
+		at += header->size;
+	}
+
+	__intel_pmu_handle_last_pebs_record(iregs, regs, data, mask,
+					    counts, last,
+					    setup_arch_pebs_sample_data);
+}
+
 static void __init intel_arch_pebs_init(void)
 {
 	/*
@@ -2762,6 +2945,7 @@ static void __init intel_arch_pebs_init(void)
 	 */
 	x86_pmu.arch_pebs = 1;
 	x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE;
+	x86_pmu.drain_pebs = intel_pmu_drain_arch_pebs;
 	x86_pmu.pebs_capable = ~0ULL;
 
 	x86_pmu.pebs_enable = __intel_pmu_pebs_enable;

arch/x86/include/asm/msr-index.h

@@ -327,6 +327,12 @@
 					 PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE | \
 					 PERF_CAP_PEBS_TIMING_INFO)
 
+/* Arch PEBS */
+#define MSR_IA32_PEBS_BASE		0x000003f4
+#define MSR_IA32_PEBS_INDEX		0x000003f5
+#define ARCH_PEBS_OFFSET_MASK		0x7fffff
+#define ARCH_PEBS_INDEX_WR_SHIFT	4
+
 #define MSR_IA32_RTIT_CTL		0x00000570
 #define RTIT_CTL_TRACEEN		BIT(0)
 #define RTIT_CTL_CYCLEACC		BIT(1)

arch/x86/include/asm/perf_event.h

@@ -437,6 +437,8 @@ static inline bool is_topdown_idx(int idx)
 #define GLOBAL_STATUS_LBRS_FROZEN		BIT_ULL(GLOBAL_STATUS_LBRS_FROZEN_BIT)
 #define GLOBAL_STATUS_TRACE_TOPAPMI_BIT		55
 #define GLOBAL_STATUS_TRACE_TOPAPMI		BIT_ULL(GLOBAL_STATUS_TRACE_TOPAPMI_BIT)
+#define GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT	54
+#define GLOBAL_STATUS_ARCH_PEBS_THRESHOLD	BIT_ULL(GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT)
 #define GLOBAL_STATUS_PERF_METRICS_OVF_BIT	48
 
 #define GLOBAL_CTRL_EN_PERF_METRICS		BIT_ULL(48)
@@ -507,6 +509,100 @@ struct pebs_cntr_header {
 
 #define INTEL_CNTR_METRICS		0x3
 
+/*
+ * Arch PEBS
+ */
+union arch_pebs_index {
+	struct {
+		u64 rsvd:4,
+		    wr:23,
+		    rsvd2:4,
+		    full:1,
+		    en:1,
+		    rsvd3:3,
+		    thresh:23,
+		    rsvd4:5;
+	};
+	u64 whole;
+};
+
+struct arch_pebs_header {
+	union {
+		u64 format;
+		struct {
+			u64 size:16,	/* Record size */
+			    rsvd:14,
+			    mode:1,	/* 64BIT_MODE */
+			    cont:1,
+			    rsvd2:3,
+			    cntr:5,
+			    lbr:2,
+			    rsvd3:7,
+			    xmm:1,
+			    ymmh:1,
+			    rsvd4:2,
+			    opmask:1,
+			    zmmh:1,
+			    h16zmm:1,
+			    rsvd5:5,
+			    gpr:1,
+			    aux:1,
+			    basic:1;
+		};
+	};
+	u64 rsvd6;
+};
+
+struct arch_pebs_basic {
+	u64 ip;
+	u64 applicable_counters;
+	u64 tsc;
+	u64 retire	:16,	/* Retire Latency */
+	    valid	:1,
+	    rsvd	:47;
+	u64 rsvd2;
+	u64 rsvd3;
+};
+
+struct arch_pebs_aux {
+	u64 address;
+	u64 rsvd;
+	u64 rsvd2;
+	u64 rsvd3;
+	u64 rsvd4;
+	u64 aux;
+	u64 instr_latency	:16,
+	    pad2		:16,
+	    cache_latency	:16,
+	    pad3		:16;
+	u64 tsx_tuning;
+};
+
+struct arch_pebs_gprs {
+	u64 flags, ip, ax, cx, dx, bx, sp, bp, si, di;
+	u64 r8, r9, r10, r11, r12, r13, r14, r15, ssp;
+	u64 rsvd;
+};
+
+struct arch_pebs_xer_header {
+	u64 xstate;
+	u64 rsvd;
+};
+
+#define ARCH_PEBS_LBR_NAN		0x0
+#define ARCH_PEBS_LBR_NUM_8		0x1
+#define ARCH_PEBS_LBR_NUM_16		0x2
+#define ARCH_PEBS_LBR_NUM_VAR		0x3
+#define ARCH_PEBS_BASE_LBR_ENTRIES	8
+struct arch_pebs_lbr_header {
+	u64 rsvd;
+	u64 ctl;
+	u64 depth;
+	u64 ler_from;
+	u64 ler_to;
+	u64 ler_info;
+};
+
 /*
  * AMD Extended Performance Monitoring and Debug cpuid feature detection
  */