Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 736 insertions, 0 deletions

diff --git a/tools/perf/util/powerpc-vpadtl.c b/tools/perf/util/powerpc-vpadtl.c
new file mode 100644
index 000000000..710f3093f
--- /dev/null
+++ b/tools/perf/util/powerpc-vpadtl.c
@@ -0,0 +1,736 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VPA DTL PMU support
+ */
+
+#include <linux/string.h>
+#include <linux/zalloc.h>
+#include <errno.h>
+#include <inttypes.h>
+#include "color.h"
+#include "evlist.h"
+#include "session.h"
+#include "auxtrace.h"
+#include "data.h"
+#include "machine.h"
+#include "debug.h"
+#include "powerpc-vpadtl.h"
+#include "sample.h"
+#include "tool.h"
+
+/*
+ * Structure to save the auxtrace queue
+ */
+struct powerpc_vpadtl {
+	struct auxtrace			auxtrace;
+	struct auxtrace_queues		queues;
+	struct auxtrace_heap		heap;
+	u32				auxtrace_type;
+	struct perf_session		*session;
+	struct machine			*machine;
+	u32				pmu_type;
+	u64				sample_id;
+};
+
+struct boottb_freq {
+	u64     boot_tb;
+	u64     tb_freq;
+	u64     timebase;
+	u64     padded[3];
+};
+
+struct powerpc_vpadtl_queue {
+	struct powerpc_vpadtl	*vpa;
+	unsigned int		queue_nr;
+	struct auxtrace_buffer	*buffer;
+	struct thread		*thread;
+	bool			on_heap;
+	struct powerpc_vpadtl_entry	*dtl;
+	u64			timestamp;
+	unsigned long		pkt_len;
+	unsigned long		buf_len;
+	u64			boot_tb;
+	u64			tb_freq;
+	unsigned int		tb_buffer;
+	unsigned int		size;
+	bool			done;
+	pid_t			pid;
+	pid_t			tid;
+	int			cpu;
+};
+
+const char *dispatch_reasons[11] = {
+	"external_interrupt",
+	"firmware_internal_event",
+	"H_PROD",
+	"decrementer_interrupt",
+	"system_reset",
+	"firmware_internal_event",
+	"conferred_cycles",
+	"time_slice",
+	"virtual_memory_page_fault",
+	"expropriated_adjunct",
+	"priv_doorbell"};
+
+const char *preempt_reasons[10] = {
+	"unused",
+	"firmware_internal_event",
+	"H_CEDE",
+	"H_CONFER",
+	"time_slice",
+	"migration_hibernation_page_fault",
+	"virtual_memory_page_fault",
+	"H_CONFER_ADJUNCT",
+	"hcall_adjunct",
+	"HDEC_adjunct"};
+
+#define	dtl_entry_size	sizeof(struct powerpc_vpadtl_entry)
+
+/*
+ * Function to dump the dispatch trace data when perf report
+ * is invoked with -D
+ */
+static void powerpc_vpadtl_dump(struct powerpc_vpadtl *vpa __maybe_unused,
+			 unsigned char *buf, size_t len)
+{
+	struct powerpc_vpadtl_entry *dtl;
+	int pkt_len, pos = 0;
+	const char *color = PERF_COLOR_BLUE;
+
+	color_fprintf(stdout, color,
+			". ... VPA DTL PMU data: size %zu bytes, entries is %zu\n",
+			len, len/dtl_entry_size);
+
+	if (len % dtl_entry_size)
+		len = len - (len % dtl_entry_size);
+
+	while (len) {
+		pkt_len = dtl_entry_size;
+		printf(".");
+		color_fprintf(stdout, color, "  %08x: ", pos);
+		dtl = (struct powerpc_vpadtl_entry *)buf;
+		if (dtl->timebase != 0) {
+			printf("dispatch_reason:%s, preempt_reason:%s, "
+					"enqueue_to_dispatch_time:%d, ready_to_enqueue_time:%d, "
+					"waiting_to_ready_time:%d\n",
+					dispatch_reasons[dtl->dispatch_reason],
+					preempt_reasons[dtl->preempt_reason],
+					be32_to_cpu(dtl->enqueue_to_dispatch_time),
+					be32_to_cpu(dtl->ready_to_enqueue_time),
+					be32_to_cpu(dtl->waiting_to_ready_time));
+		} else {
+			struct boottb_freq *boot_tb = (struct boottb_freq *)buf;
+
+			printf("boot_tb: %" PRIu64 ", tb_freq: %" PRIu64 "\n",
+					boot_tb->boot_tb, boot_tb->tb_freq);
+		}
+
+		pos += pkt_len;
+		buf += pkt_len;
+		len -= pkt_len;
+	}
+}
+
+static unsigned long long powerpc_vpadtl_timestamp(struct powerpc_vpadtl_queue *vpaq)
+{
+	struct powerpc_vpadtl_entry *record = vpaq->dtl;
+	unsigned long long timestamp = 0;
+	unsigned long long boot_tb;
+	unsigned long long diff;
+	double result, div;
+	double boot_freq;
+	/*
+	 * Formula used to get timestamp that can be co-related with
+	 * other perf events:
+	 * ((timbase from DTL entry - boot time) / frequency) * 1000000000
+	 */
+	if (record->timebase) {
+		boot_tb = vpaq->boot_tb;
+		boot_freq = vpaq->tb_freq;
+		diff = be64_to_cpu(record->timebase) - boot_tb;
+		div = diff / boot_freq;
+		result = div;
+		result = result * 1000000000;
+		timestamp = result;
+	}
+
+	return timestamp;
+}
+
+static struct powerpc_vpadtl *session_to_vpa(struct perf_session *session)
+{
+	return container_of(session->auxtrace, struct powerpc_vpadtl, auxtrace);
+}
+
+static void powerpc_vpadtl_dump_event(struct powerpc_vpadtl *vpa, unsigned char *buf,
+			       size_t len)
+{
+	printf(".\n");
+	powerpc_vpadtl_dump(vpa, buf, len);
+}
+
+/*
+ * Generate perf sample for each entry in the dispatch trace log.
+ *   - sample ip is picked from srr0 field of powerpc_vpadtl_entry
+ *   - sample cpu is logical cpu.
+ *   - cpumode is set to PERF_RECORD_MISC_KERNEL
+ *   - Additionally save the details in raw_data of sample. This
+ *   is to print the relevant fields in perf_sample__fprintf_synth()
+ *   when called from builtin-script
+ */
+static int powerpc_vpadtl_sample(struct powerpc_vpadtl_entry *record,
+		struct powerpc_vpadtl *vpa, u64 save, int cpu)
+{
+	struct perf_sample sample;
+	union perf_event event;
+	int ret;
+
+	perf_sample__init(&sample, /*all=*/true);
+	sample.ip = be64_to_cpu(record->srr0);
+	sample.period = 1;
+	sample.cpu = cpu;
+	sample.id = vpa->sample_id;
+	sample.callchain = NULL;
+	sample.branch_stack = NULL;
+	memset(&event, 0, sizeof(event));
+	sample.cpumode = PERF_RECORD_MISC_KERNEL;
+	sample.time = save;
+	sample.raw_data = record;
+	sample.raw_size = sizeof(record);
+	event.sample.header.type = PERF_RECORD_SAMPLE;
+	event.sample.header.misc = sample.cpumode;
+	event.sample.header.size = sizeof(struct perf_event_header);
+
+	ret = perf_session__deliver_synth_event(vpa->session, &event, &sample);
+	if (ret)
+		pr_debug("Failed to create sample for dtl entry\n");
+
+	perf_sample__exit(&sample);
+	return ret;
+}
+
+static int powerpc_vpadtl_get_buffer(struct powerpc_vpadtl_queue *vpaq)
+{
+	struct auxtrace_buffer *buffer = vpaq->buffer;
+	struct auxtrace_queues *queues = &vpaq->vpa->queues;
+	struct auxtrace_queue *queue;
+
+	queue = &queues->queue_array[vpaq->queue_nr];
+	buffer = auxtrace_buffer__next(queue, buffer);
+
+	if (!buffer)
+		return 0;
+
+	vpaq->buffer = buffer;
+	vpaq->size = buffer->size;
+
+	/* If the aux_buffer doesn't have data associated, try to load it */
+	if (!buffer->data) {
+		/* get the file desc associated with the perf data file */
+		int fd = perf_data__fd(vpaq->vpa->session->data);
+
+		buffer->data = auxtrace_buffer__get_data(buffer, fd);
+		if (!buffer->data)
+			return -ENOMEM;
+	}
+
+	vpaq->buf_len = buffer->size;
+
+	if (buffer->size % dtl_entry_size)
+		vpaq->buf_len = buffer->size - (buffer->size % dtl_entry_size);
+
+	if (vpaq->tb_buffer != buffer->buffer_nr) {
+		vpaq->pkt_len = 0;
+		vpaq->tb_buffer = 0;
+	}
+
+	return 1;
+}
+
+/*
+ * The first entry in the queue for VPA DTL PMU has the boot timebase,
+ * frequency details which are needed to get timestamp which is required to
+ * correlate with other events. Save the boot_tb and tb_freq as part of
+ * powerpc_vpadtl_queue. The very next entry is the actual trace data to
+ * be returned.
+ */
+static int powerpc_vpadtl_decode(struct powerpc_vpadtl_queue *vpaq)
+{
+	int ret;
+	char *buf;
+	struct boottb_freq *boottb;
+
+	ret = powerpc_vpadtl_get_buffer(vpaq);
+	if (ret <= 0)
+		return ret;
+
+	boottb = (struct boottb_freq *)vpaq->buffer->data;
+	if (boottb->timebase == 0) {
+		vpaq->boot_tb = boottb->boot_tb;
+		vpaq->tb_freq = boottb->tb_freq;
+		vpaq->pkt_len += dtl_entry_size;
+	}
+
+	buf = vpaq->buffer->data;
+	buf += vpaq->pkt_len;
+	vpaq->dtl = (struct powerpc_vpadtl_entry *)buf;
+
+	vpaq->tb_buffer = vpaq->buffer->buffer_nr;
+	vpaq->buffer = NULL;
+	vpaq->buf_len = 0;
+
+	return 1;
+}
+
+static int powerpc_vpadtl_decode_all(struct powerpc_vpadtl_queue *vpaq)
+{
+	int ret;
+	unsigned char *buf;
+
+	if (!vpaq->buf_len || vpaq->pkt_len == vpaq->size) {
+		ret = powerpc_vpadtl_get_buffer(vpaq);
+		if (ret <= 0)
+			return ret;
+	}
+
+	if (vpaq->buffer) {
+		buf = vpaq->buffer->data;
+		buf += vpaq->pkt_len;
+		vpaq->dtl = (struct powerpc_vpadtl_entry *)buf;
+		if ((long long)be64_to_cpu(vpaq->dtl->timebase) <= 0) {
+			if (vpaq->pkt_len != dtl_entry_size && vpaq->buf_len) {
+				vpaq->pkt_len += dtl_entry_size;
+				vpaq->buf_len -= dtl_entry_size;
+			}
+			return -1;
+		}
+		vpaq->pkt_len += dtl_entry_size;
+		vpaq->buf_len -= dtl_entry_size;
+	} else {
+		return 0;
+	}
+
+	return 1;
+}
+
+static int powerpc_vpadtl_run_decoder(struct powerpc_vpadtl_queue *vpaq, u64 *timestamp)
+{
+	struct powerpc_vpadtl *vpa = vpaq->vpa;
+	struct powerpc_vpadtl_entry *record;
+	int ret;
+	unsigned long long vpaq_timestamp;
+
+	while (1) {
+		ret = powerpc_vpadtl_decode_all(vpaq);
+		if (!ret) {
+			pr_debug("All data in the queue has been processed.\n");
+			return 1;
+		}
+
+		/*
+		 * Error is detected when decoding VPA PMU trace. Continue to
+		 * the next trace data and find out more dtl entries.
+		 */
+		if (ret < 0)
+			continue;
+
+		record = vpaq->dtl;
+
+		vpaq_timestamp = powerpc_vpadtl_timestamp(vpaq);
+
+		/* Update timestamp for the last record */
+		if (vpaq_timestamp > vpaq->timestamp)
+			vpaq->timestamp = vpaq_timestamp;
+
+		/*
+		 * If the timestamp of the queue is later than timestamp of the
+		 * coming perf event, bail out so can allow the perf event to
+		 * be processed ahead.
+		 */
+		if (vpaq->timestamp >= *timestamp) {
+			*timestamp = vpaq->timestamp;
+			vpaq->pkt_len -= dtl_entry_size;
+			vpaq->buf_len += dtl_entry_size;
+			return 0;
+		}
+
+		ret = powerpc_vpadtl_sample(record, vpa, vpaq_timestamp, vpaq->cpu);
+		if (ret)
+			continue;
+	}
+	return 0;
+}
+
+/*
+ * For each of the PERF_RECORD_XX record, compare the timestamp
+ * of perf record with timestamp of top element in the auxtrace heap.
+ * Process the auxtrace queue if the timestamp of element from heap is
+ * lower than timestamp from entry in perf record.
+ *
+ * Update the timestamp of the auxtrace heap with the timestamp
+ * of last processed entry from the auxtrace buffer.
+ */
+static int powerpc_vpadtl_process_queues(struct powerpc_vpadtl *vpa, u64 timestamp)
+{
+	unsigned int queue_nr;
+	u64 ts;
+	int ret;
+
+	while (1) {
+		struct auxtrace_queue *queue;
+		struct powerpc_vpadtl_queue *vpaq;
+
+		if (!vpa->heap.heap_cnt)
+			return 0;
+
+		if (vpa->heap.heap_array[0].ordinal >= timestamp)
+			return 0;
+
+		queue_nr = vpa->heap.heap_array[0].queue_nr;
+		queue = &vpa->queues.queue_array[queue_nr];
+		vpaq = queue->priv;
+
+		auxtrace_heap__pop(&vpa->heap);
+
+		if (vpa->heap.heap_cnt) {
+			ts = vpa->heap.heap_array[0].ordinal + 1;
+			if (ts > timestamp)
+				ts = timestamp;
+		} else {
+			ts = timestamp;
+		}
+
+		ret = powerpc_vpadtl_run_decoder(vpaq, &ts);
+		if (ret < 0) {
+			auxtrace_heap__add(&vpa->heap, queue_nr, ts);
+			return ret;
+		}
+
+		if (!ret) {
+			ret = auxtrace_heap__add(&vpa->heap, queue_nr, ts);
+			if (ret < 0)
+				return ret;
+		} else {
+			vpaq->on_heap = false;
+		}
+	}
+	return 0;
+}
+
+static struct powerpc_vpadtl_queue *powerpc_vpadtl__alloc_queue(struct powerpc_vpadtl *vpa,
+						unsigned int queue_nr)
+{
+	struct powerpc_vpadtl_queue *vpaq;
+
+	vpaq = zalloc(sizeof(*vpaq));
+	if (!vpaq)
+		return NULL;
+
+	vpaq->vpa = vpa;
+	vpaq->queue_nr = queue_nr;
+
+	return vpaq;
+}
+
+/*
+ * When the Dispatch Trace Log data is collected along with other events
+ * like sched tracepoint events, it needs to be correlated and present
+ * interleaved along with these events. Perf events can be collected
+ * parallely across the CPUs.
+ *
+ * An auxtrace_queue is created for each CPU. Data within each queue is in
+ * increasing order of timestamp. Allocate and setup auxtrace queues here.
+ * All auxtrace queues is maintained in auxtrace heap in the increasing order
+ * of timestamp. So always the lowest timestamp (entries to be processed first)
+ * is on top of the heap.
+ *
+ * To add to auxtrace heap, fetch the timestamp from first DTL entry
+ * for each of the queue.
+ */
+static int powerpc_vpadtl__setup_queue(struct powerpc_vpadtl *vpa,
+		struct auxtrace_queue *queue,
+		unsigned int queue_nr)
+{
+	struct powerpc_vpadtl_queue *vpaq = queue->priv;
+
+	if (list_empty(&queue->head) || vpaq)
+		return 0;
+
+	vpaq = powerpc_vpadtl__alloc_queue(vpa, queue_nr);
+	if (!vpaq)
+		return -ENOMEM;
+
+	queue->priv = vpaq;
+
+	if (queue->cpu != -1)
+		vpaq->cpu = queue->cpu;
+
+	if (!vpaq->on_heap) {
+		int ret;
+retry:
+		ret = powerpc_vpadtl_decode(vpaq);
+		if (!ret)
+			return 0;
+
+		if (ret < 0)
+			goto retry;
+
+		vpaq->timestamp = powerpc_vpadtl_timestamp(vpaq);
+
+		ret = auxtrace_heap__add(&vpa->heap, queue_nr, vpaq->timestamp);
+		if (ret)
+			return ret;
+		vpaq->on_heap = true;
+	}
+
+	return 0;
+}
+
+static int powerpc_vpadtl__setup_queues(struct powerpc_vpadtl *vpa)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < vpa->queues.nr_queues; i++) {
+		ret = powerpc_vpadtl__setup_queue(vpa, &vpa->queues.queue_array[i], i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int powerpc_vpadtl__update_queues(struct powerpc_vpadtl *vpa)
+{
+	if (vpa->queues.new_data) {
+		vpa->queues.new_data = false;
+		return powerpc_vpadtl__setup_queues(vpa);
+	}
+
+	return 0;
+}
+
+static int powerpc_vpadtl_process_event(struct perf_session *session,
+				 union perf_event *event __maybe_unused,
+				 struct perf_sample *sample,
+				 const struct perf_tool *tool)
+{
+	struct powerpc_vpadtl *vpa = session_to_vpa(session);
+	int err = 0;
+
+	if (dump_trace)
+		return 0;
+
+	if (!tool->ordered_events) {
+		pr_err("VPA requires ordered events\n");
+		return -EINVAL;
+	}
+
+	if (sample->time) {
+		err = powerpc_vpadtl__update_queues(vpa);
+		if (err)
+			return err;
+
+		err = powerpc_vpadtl_process_queues(vpa, sample->time);
+	}
+
+	return err;
+}
+
+/*
+ * Process PERF_RECORD_AUXTRACE records
+ */
+static int powerpc_vpadtl_process_auxtrace_event(struct perf_session *session,
+					  union perf_event *event,
+					  const struct perf_tool *tool __maybe_unused)
+{
+	struct powerpc_vpadtl *vpa = session_to_vpa(session);
+	struct auxtrace_buffer *buffer;
+	int fd = perf_data__fd(session->data);
+	off_t data_offset;
+	int err;
+
+	if (!dump_trace)
+		return 0;
+
+	if (perf_data__is_pipe(session->data)) {
+		data_offset = 0;
+	} else {
+		data_offset = lseek(fd, 0, SEEK_CUR);
+		if (data_offset == -1)
+			return -errno;
+	}
+
+	err = auxtrace_queues__add_event(&vpa->queues, session, event,
+			data_offset, &buffer);
+
+	if (err)
+		return err;
+
+	/* Dump here now we have copied a piped trace out of the pipe */
+	if (auxtrace_buffer__get_data(buffer, fd)) {
+		powerpc_vpadtl_dump_event(vpa, buffer->data, buffer->size);
+		auxtrace_buffer__put_data(buffer);
+	}
+
+	return 0;
+}
+
+static int powerpc_vpadtl_flush(struct perf_session *session __maybe_unused,
+			 const struct perf_tool *tool __maybe_unused)
+{
+	return 0;
+}
+
+static void powerpc_vpadtl_free_events(struct perf_session *session)
+{
+	struct powerpc_vpadtl *vpa = session_to_vpa(session);
+	struct auxtrace_queues *queues = &vpa->queues;
+
+	for (unsigned int i = 0; i < queues->nr_queues; i++)
+		zfree(&queues->queue_array[i].priv);
+
+	auxtrace_queues__free(queues);
+}
+
+static void powerpc_vpadtl_free(struct perf_session *session)
+{
+	struct powerpc_vpadtl *vpa = session_to_vpa(session);
+
+	auxtrace_heap__free(&vpa->heap);
+	powerpc_vpadtl_free_events(session);
+	session->auxtrace = NULL;
+	free(vpa);
+}
+
+static const char * const powerpc_vpadtl_info_fmts[] = {
+	[POWERPC_VPADTL_TYPE]		= "  PMU Type           %"PRId64"\n",
+};
+
+static void powerpc_vpadtl_print_info(__u64 *arr)
+{
+	if (!dump_trace)
+		return;
+
+	fprintf(stdout, powerpc_vpadtl_info_fmts[POWERPC_VPADTL_TYPE], arr[POWERPC_VPADTL_TYPE]);
+}
+
+static void set_event_name(struct evlist *evlist, u64 id,
+		const char *name)
+{
+	struct evsel *evsel;
+
+	evlist__for_each_entry(evlist, evsel) {
+		if (evsel->core.id && evsel->core.id[0] == id) {
+			if (evsel->name)
+				zfree(&evsel->name);
+			evsel->name = strdup(name);
+			break;
+		}
+	}
+}
+
+static int
+powerpc_vpadtl_synth_events(struct powerpc_vpadtl *vpa, struct perf_session *session)
+{
+	struct evlist *evlist = session->evlist;
+	struct evsel *evsel;
+	struct perf_event_attr attr;
+	bool found = false;
+	u64 id;
+	int err;
+
+	evlist__for_each_entry(evlist, evsel) {
+		if (strstarts(evsel->name, "vpa_dtl")) {
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		pr_debug("No selected events with VPA trace data\n");
+		return 0;
+	}
+
+	memset(&attr, 0, sizeof(struct perf_event_attr));
+	attr.size = sizeof(struct perf_event_attr);
+	attr.sample_type = evsel->core.attr.sample_type;
+	attr.sample_id_all = evsel->core.attr.sample_id_all;
+	attr.type = PERF_TYPE_SYNTH;
+	attr.config = PERF_SYNTH_POWERPC_VPA_DTL;
+
+	/* create new id val to be a fixed offset from evsel id */
+	id = auxtrace_synth_id_range_start(evsel);
+
+	err = perf_session__deliver_synth_attr_event(session, &attr, id);
+	if (err)
+		return err;
+
+	vpa->sample_id = id;
+	set_event_name(evlist, id, "vpa-dtl");
+
+	return 0;
+}
+
+/*
+ * Process the PERF_RECORD_AUXTRACE_INFO records and setup
+ * the infrastructure to process auxtrace events. PERF_RECORD_AUXTRACE_INFO
+ * is processed first since it is of type perf_user_event_type.
+ * Initialise the aux buffer queues using auxtrace_queues__init().
+ * auxtrace_queue is created for each CPU.
+ */
+int powerpc_vpadtl_process_auxtrace_info(union perf_event *event,
+				  struct perf_session *session)
+{
+	struct perf_record_auxtrace_info *auxtrace_info = &event->auxtrace_info;
+	size_t min_sz = sizeof(u64) * POWERPC_VPADTL_TYPE;
+	struct powerpc_vpadtl *vpa;
+	int err;
+
+	if (auxtrace_info->header.size < sizeof(struct perf_record_auxtrace_info) +
+					min_sz)
+		return -EINVAL;
+
+	vpa = zalloc(sizeof(struct powerpc_vpadtl));
+	if (!vpa)
+		return -ENOMEM;
+
+	err = auxtrace_queues__init(&vpa->queues);
+	if (err)
+		goto err_free;
+
+	vpa->session = session;
+	vpa->machine = &session->machines.host; /* No kvm support */
+	vpa->auxtrace_type = auxtrace_info->type;
+	vpa->pmu_type = auxtrace_info->priv[POWERPC_VPADTL_TYPE];
+
+	vpa->auxtrace.process_event = powerpc_vpadtl_process_event;
+	vpa->auxtrace.process_auxtrace_event = powerpc_vpadtl_process_auxtrace_event;
+	vpa->auxtrace.flush_events = powerpc_vpadtl_flush;
+	vpa->auxtrace.free_events = powerpc_vpadtl_free_events;
+	vpa->auxtrace.free = powerpc_vpadtl_free;
+	session->auxtrace = &vpa->auxtrace;
+
+	powerpc_vpadtl_print_info(&auxtrace_info->priv[0]);
+
+	if (dump_trace)
+		return 0;
+
+	err = powerpc_vpadtl_synth_events(vpa, session);
+	if (err)
+		goto err_free_queues;
+
+	err = auxtrace_queues__process_index(&vpa->queues, session);
+	if (err)
+		goto err_free_queues;
+
+	return 0;
+
+err_free_queues:
+	auxtrace_queues__free(&vpa->queues);
+	session->auxtrace = NULL;
+
+err_free:
+	free(vpa);
+	return err;
+}