perf fixes

index 3ea25c3917c0..feb90f6730e8 100644
@@ -28,10 +28,46 @@ static u32 ibs_caps;
 #define IBS_FETCH_CONFIG_MASK	(IBS_FETCH_RAND_EN | IBS_FETCH_MAX_CNT)
 #define IBS_OP_CONFIG_MASK	IBS_OP_MAX_CNT
 
+
+/*
+ * IBS states:
+ *
+ * ENABLED; tracks the pmu::add(), pmu::del() state, when set the counter is taken
+ * and any further add()s must fail.
+ *
+ * STARTED/STOPPING/STOPPED; deal with pmu::start(), pmu::stop() state but are
+ * complicated by the fact that the IBS hardware can send late NMIs (ie. after
+ * we've cleared the EN bit).
+ *
+ * In order to consume these late NMIs we have the STOPPED state, any NMI that
+ * happens after we've cleared the EN state will clear this bit and report the
+ * NMI handled (this is fundamentally racy in the face or multiple NMI sources,
+ * someone else can consume our BIT and our NMI will go unhandled).
+ *
+ * And since we cannot set/clear this separate bit together with the EN bit,
+ * there are races; if we cleared STARTED early, an NMI could land in
+ * between clearing STARTED and clearing the EN bit (in fact multiple NMIs
+ * could happen if the period is small enough), and consume our STOPPED bit
+ * and trigger streams of unhandled NMIs.
+ *
+ * If, however, we clear STARTED late, an NMI can hit between clearing the
+ * EN bit and clearing STARTED, still see STARTED set and process the event.
+ * If this event will have the VALID bit clear, we bail properly, but this
+ * is not a given. With VALID set we can end up calling pmu::stop() again
+ * (the throttle logic) and trigger the WARNs in there.
+ *
+ * So what we do is set STOPPING before clearing EN to avoid the pmu::stop()
+ * nesting, and clear STARTED late, so that we have a well defined state over
+ * the clearing of the EN bit.
+ *
+ * XXX: we could probably be using !atomic bitops for all this.
+ */
+
 enum ibs_states {
 	IBS_ENABLED	= 0,
 	IBS_STARTED	= 1,
 	IBS_STOPPING	= 2,
+	IBS_STOPPED	= 3,
 
 	IBS_MAX_STATES,
 };

@@ -377,11 +413,10 @@ static void perf_ibs_start(struct perf_event *event, int flags)
 
 	perf_ibs_set_period(perf_ibs, hwc, &period);
 	/*
-	 * Set STARTED before enabling the hardware, such that
-	 * a subsequent NMI must observe it. Then clear STOPPING
-	 * such that we don't consume NMIs by accident.
+	 * Set STARTED before enabling the hardware, such that a subsequent NMI
+	 * must observe it.
 	 */
-	set_bit(IBS_STARTED, pcpu->state);
+	set_bit(IBS_STARTED,    pcpu->state);
 	clear_bit(IBS_STOPPING, pcpu->state);
 	perf_ibs_enable_event(perf_ibs, hwc, period >> 4);
 

@@ -396,6 +431,9 @@ static void perf_ibs_stop(struct perf_event *event, int flags)
 	u64 config;
 	int stopping;
 
+	if (test_and_set_bit(IBS_STOPPING, pcpu->state))
+		return;
+
 	stopping = test_bit(IBS_STARTED, pcpu->state);
 
 	if (!stopping && (hwc->state & PERF_HES_UPTODATE))

@@ -405,12 +443,12 @@ static void perf_ibs_stop(struct perf_event *event, int flags)
 
 	if (stopping) {
 		/*
-		 * Set STOPPING before disabling the hardware, such that it
+		 * Set STOPPED before disabling the hardware, such that it
 		 * must be visible to NMIs the moment we clear the EN bit,
 		 * at which point we can generate an !VALID sample which
 		 * we need to consume.
 		 */
-		set_bit(IBS_STOPPING, pcpu->state);
+		set_bit(IBS_STOPPED, pcpu->state);
 		perf_ibs_disable_event(perf_ibs, hwc, config);
 		/*
 		 * Clear STARTED after disabling the hardware; if it were

@@ -556,7 +594,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 		 * with samples that even have the valid bit cleared.
 		 * Mark all this NMIs as handled.
 		 */
-		if (test_and_clear_bit(IBS_STOPPING, pcpu->state))
+		if (test_and_clear_bit(IBS_STOPPED, pcpu->state))
 			return 1;
 
 		return 0;

index ba6ef18528c9..a6771e2303d2 100644
@@ -795,6 +795,9 @@ ssize_t intel_event_sysfs_show(char *page, u64 config);
 
 struct attribute **merge_attr(struct attribute **a, struct attribute **b);
 
+ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr,
+			  char *page);
+
 #ifdef CONFIG_CPU_SUP_AMD
 
 int amd_pmu_init(void);

@@ -925,9 +928,6 @@ int p6_pmu_init(void);
 
 int knc_pmu_init(void);
 
-ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr,
-			  char *page);
-
 static inline int is_ht_workaround_enabled(void)
 {
 	return !!(x86_pmu.flags & PMU_FL_EXCL_ENABLED);

index de24fbce5277..52bedc5a5aaa 100644
@@ -2417,14 +2417,24 @@ static void ctx_sched_out(struct perf_event_context *ctx,
 			cpuctx->task_ctx = NULL;
 	}
 
-	is_active ^= ctx->is_active; /* changed bits */
-
+	/*
+	 * Always update time if it was set; not only when it changes.
+	 * Otherwise we can 'forget' to update time for any but the last
+	 * context we sched out. For example:
+	 *
+	 *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
+	 *   ctx_sched_out(.event_type = EVENT_PINNED)
+	 *
+	 * would only update time for the pinned events.
+	 */
 	if (is_active & EVENT_TIME) {
 		/* update (and stop) ctx time */
 		update_context_time(ctx);
 		update_cgrp_time_from_cpuctx(cpuctx);
 	}
 
+	is_active ^= ctx->is_active; /* changed bits */
+
 	if (!ctx->nr_active || !(is_active & EVENT_ALL))
 		return;
 

@@ -8532,6 +8542,7 @@ SYSCALL_DEFINE5(perf_event_open,
 					f_flags);
 	if (IS_ERR(event_file)) {
 		err = PTR_ERR(event_file);
+		event_file = NULL;
 		goto err_context;
 	}
 

index 6138bdef6e63..f8ccee132867 100644
@@ -4,6 +4,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include <linux/stringify.h>
+#include "header.h"
+#include "util.h"
 
 #define mfspr(rn)       ({unsigned long rval; \
 			 asm volatile("mfspr %0," __stringify(rn) \

index 4b9816555946..2a83414159a6 100644
@@ -337,7 +337,7 @@ static void callchain_node__init_have_children(struct callchain_node *node,
 	chain = list_entry(node->val.next, struct callchain_list, list);
 	chain->has_children = has_sibling;
 
-	if (node->val.next != node->val.prev) {
+	if (!list_empty(&node->val)) {
 		chain = list_entry(node->val.prev, struct callchain_list, list);
 		chain->has_children = !RB_EMPTY_ROOT(&node->rb_root);
 	}

index 52cf479bc593..dad55d04ffdd 100644
@@ -56,13 +56,22 @@ const char *perf_event__name(unsigned int id)
 	return perf_event__names[id];
 }
 
-static struct perf_sample synth_sample = {
+static int perf_tool__process_synth_event(struct perf_tool *tool,
+					  union perf_event *event,
+					  struct machine *machine,
+					  perf_event__handler_t process)
+{
+	struct perf_sample synth_sample = {
 	.pid	   = -1,
 	.tid	   = -1,
 	.time	   = -1,
 	.stream_id = -1,
 	.cpu	   = -1,
 	.period	   = 1,
+	.cpumode   = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK,
+	};
+
+	return process(tool, event, &synth_sample, machine);
 };
 
 /*

@@ -186,7 +195,7 @@ pid_t perf_event__synthesize_comm(struct perf_tool *tool,
 	if (perf_event__prepare_comm(event, pid, machine, &tgid, &ppid) != 0)
 		return -1;
 
-	if (process(tool, event, &synth_sample, machine) != 0)
+	if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
 		return -1;
 
 	return tgid;

@@ -218,7 +227,7 @@ static int perf_event__synthesize_fork(struct perf_tool *tool,
 
 	event->fork.header.size = (sizeof(event->fork) + machine->id_hdr_size);
 
-	if (process(tool, event, &synth_sample, machine) != 0)
+	if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
 		return -1;
 
 	return 0;

@@ -344,7 +353,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 		event->mmap2.pid = tgid;
 		event->mmap2.tid = pid;
 
-		if (process(tool, event, &synth_sample, machine) != 0) {
+		if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
 			rc = -1;
 			break;
 		}

@@ -402,7 +411,7 @@ int perf_event__synthesize_modules(struct perf_tool *tool,
 
 		memcpy(event->mmap.filename, pos->dso->long_name,
 		       pos->dso->long_name_len + 1);
-		if (process(tool, event, &synth_sample, machine) != 0) {
+		if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
 			rc = -1;
 			break;
 		}

@@ -472,7 +481,7 @@ static int __event__synthesize_thread(union perf_event *comm_event,
 		/*
 		 * Send the prepared comm event
 		 */
-		if (process(tool, comm_event, &synth_sample, machine) != 0)
+		if (perf_tool__process_synth_event(tool, comm_event, machine, process) != 0)
 			break;
 
 		rc = 0;

@@ -701,7 +710,7 @@ int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
 	event->mmap.len   = map->end - event->mmap.start;
 	event->mmap.pid   = machine->pid;
 
-	err = process(tool, event, &synth_sample, machine);
+	err = perf_tool__process_synth_event(tool, event, machine, process);
 	free(event);
 
 	return err;

index cd67e64a0494..2fbeb59c4bdd 100644
@@ -9,36 +9,32 @@ int jit_add_debug_info(Elf *e, uint64_t code_addr, void *debug, int nr_debug_ent
 
 #if   defined(__arm__)
 #define GEN_ELF_ARCH	EM_ARM
-#define GEN_ELF_ENDIAN	ELFDATA2LSB
 #define GEN_ELF_CLASS	ELFCLASS32
 #elif defined(__aarch64__)
 #define GEN_ELF_ARCH	EM_AARCH64
-#define GEN_ELF_ENDIAN	ELFDATA2LSB
 #define GEN_ELF_CLASS	ELFCLASS64
 #elif defined(__x86_64__)
 #define GEN_ELF_ARCH	EM_X86_64
-#define GEN_ELF_ENDIAN	ELFDATA2LSB
 #define GEN_ELF_CLASS	ELFCLASS64
 #elif defined(__i386__)
 #define GEN_ELF_ARCH	EM_386
-#define GEN_ELF_ENDIAN	ELFDATA2LSB
 #define GEN_ELF_CLASS	ELFCLASS32
-#elif defined(__ppcle__)
-#define GEN_ELF_ARCH	EM_PPC
-#define GEN_ELF_ENDIAN	ELFDATA2LSB
-#define GEN_ELF_CLASS	ELFCLASS64
-#elif defined(__powerpc__)
-#define GEN_ELF_ARCH	EM_PPC64
-#define GEN_ELF_ENDIAN	ELFDATA2MSB
-#define GEN_ELF_CLASS	ELFCLASS64
-#elif defined(__powerpcle__)
+#elif defined(__powerpc64__)
 #define GEN_ELF_ARCH	EM_PPC64
-#define GEN_ELF_ENDIAN	ELFDATA2LSB
 #define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__powerpc__)
+#define GEN_ELF_ARCH	EM_PPC
+#define GEN_ELF_CLASS	ELFCLASS32
 #else
 #error "unsupported architecture"
 #endif
 
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define GEN_ELF_ENDIAN	ELFDATA2MSB
+#else
+#define GEN_ELF_ENDIAN	ELFDATA2LSB
+#endif
+
 #if GEN_ELF_CLASS == ELFCLASS64
 #define elf_newehdr	elf64_newehdr
 #define elf_getshdr	elf64_getshdr

index 6bc3ecd2e7ca..abf1366e2a24 100644
@@ -279,6 +279,7 @@ static int intel_bts_synth_branch_sample(struct intel_bts_queue *btsq,
 	event.sample.header.misc = PERF_RECORD_MISC_USER;
 	event.sample.header.size = sizeof(struct perf_event_header);
 
+	sample.cpumode = PERF_RECORD_MISC_USER;
 	sample.ip = le64_to_cpu(branch->from);
 	sample.pid = btsq->pid;
 	sample.tid = btsq->tid;

index 05d815851be1..407f11b97c8d 100644
@@ -979,6 +979,7 @@ static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)
 	if (!pt->timeless_decoding)
 		sample.time = tsc_to_perf_time(ptq->timestamp, &pt->tc);
 
+	sample.cpumode = PERF_RECORD_MISC_USER;
 	sample.ip = ptq->state->from_ip;
 	sample.pid = ptq->pid;
 	sample.tid = ptq->tid;

@@ -1035,6 +1036,7 @@ static int intel_pt_synth_instruction_sample(struct intel_pt_queue *ptq)
 	if (!pt->timeless_decoding)
 		sample.time = tsc_to_perf_time(ptq->timestamp, &pt->tc);
 
+	sample.cpumode = PERF_RECORD_MISC_USER;
 	sample.ip = ptq->state->from_ip;
 	sample.pid = ptq->pid;
 	sample.tid = ptq->tid;

@@ -1092,6 +1094,7 @@ static int intel_pt_synth_transaction_sample(struct intel_pt_queue *ptq)
 	if (!pt->timeless_decoding)
 		sample.time = tsc_to_perf_time(ptq->timestamp, &pt->tc);
 
+	sample.cpumode = PERF_RECORD_MISC_USER;
 	sample.ip = ptq->state->from_ip;
 	sample.pid = ptq->pid;
 	sample.tid = ptq->tid;

index cd272cc21e05..ad0c0bb1fbc7 100644
@@ -417,6 +417,7 @@ static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr)
 	 * use first address as sample address
 	 */
 	memset(&sample, 0, sizeof(sample));
+	sample.cpumode = PERF_RECORD_MISC_USER;
 	sample.pid  = pid;
 	sample.tid  = tid;
 	sample.time = id->time;

@@ -505,6 +506,7 @@ static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr)
 	 * use first address as sample address
 	 */
 	memset(&sample, 0, sizeof(sample));
+	sample.cpumode = PERF_RECORD_MISC_USER;
 	sample.pid  = pid;
 	sample.tid  = tid;
 	sample.time = id->time;