Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Added new "bootconfig".

   This looks for a file appended to initrd to add boot config options,
   and has been discussed thoroughly at Linux Plumbers.

   Very useful for adding kprobes at bootup.

   Only enabled if "bootconfig" is on the real kernel command line.

 - Created dynamic event creation.

   Merges common code between creating synthetic events and kprobe
   events.

 - Rename perf "ring_buffer" structure to "perf_buffer"

 - Rename ftrace "ring_buffer" structure to "trace_buffer"

   Had to rename existing "trace_buffer" to "array_buffer"

 - Allow trace_printk() to work withing (some) tracing code.

 - Sort of tracing configs to be a little better organized

 - Fixed bug where ftrace_graph hash was not being protected properly

 - Various other small fixes and clean ups

* tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits)
  bootconfig: Show the number of nodes on boot message
  tools/bootconfig: Show the number of bootconfig nodes
  bootconfig: Add more parse error messages
  bootconfig: Use bootconfig instead of boot config
  ftrace: Protect ftrace_graph_hash with ftrace_sync
  ftrace: Add comment to why rcu_dereference_sched() is open coded
  tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu
  tracing: Annotate ftrace_graph_hash pointer with __rcu
  bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline
  tracing: Use seq_buf for building dynevent_cmd string
  tracing: Remove useless code in dynevent_arg_pair_add()
  tracing: Remove check_arg() callbacks from dynevent args
  tracing: Consolidate some synth_event_trace code
  tracing: Fix now invalid var_ref_vals assumption in trace action
  tracing: Change trace_boot to use synth_event interface
  tracing: Move tracing selftests to bottom of menu
  tracing: Move mmio tracer config up with the other tracers
  tracing: Move tracing test module configs together
  tracing: Move all function tracing configs together
  tracing: Documentation for in-kernel synthetic event API
  ...

1 files changed, 334 insertions, 0 deletions

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
new file mode 100644
index 000000000000..06d7feb5255f
--- /dev/null
+++ b/kernel/trace/trace_boot.c
@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_boot.c
+ * Tracing kernel boot-time
+ */
+
+#define pr_fmt(fmt)	"trace_boot: " fmt
+
+#include <linux/bootconfig.h>
+#include <linux/cpumask.h>
+#include <linux/ftrace.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/trace.h>
+#include <linux/trace_events.h>
+
+#include "trace.h"
+
+#define MAX_BUF_LEN 256
+
+static void __init
+trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *anode;
+	const char *p;
+	char buf[MAX_BUF_LEN];
+	unsigned long v = 0;
+
+	/* Common ftrace options */
+	xbc_node_for_each_array_value(node, "options", anode, p) {
+		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
+			pr_err("String is too long: %s\n", p);
+			continue;
+		}
+
+		if (trace_set_options(tr, buf) < 0)
+			pr_err("Failed to set option: %s\n", buf);
+	}
+
+	p = xbc_node_find_value(node, "trace_clock", NULL);
+	if (p && *p != '\0') {
+		if (tracing_set_clock(tr, p) < 0)
+			pr_err("Failed to set trace clock: %s\n", p);
+	}
+
+	p = xbc_node_find_value(node, "buffer_size", NULL);
+	if (p && *p != '\0') {
+		v = memparse(p, NULL);
+		if (v < PAGE_SIZE)
+			pr_err("Buffer size is too small: %s\n", p);
+		if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
+			pr_err("Failed to resize trace buffer to %s\n", p);
+	}
+
+	p = xbc_node_find_value(node, "cpumask", NULL);
+	if (p && *p != '\0') {
+		cpumask_var_t new_mask;
+
+		if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+			if (cpumask_parse(p, new_mask) < 0 ||
+			    tracing_set_cpumask(tr, new_mask) < 0)
+				pr_err("Failed to set new CPU mask %s\n", p);
+			free_cpumask_var(new_mask);
+		}
+	}
+}
+
+#ifdef CONFIG_EVENT_TRACING
+static void __init
+trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *p;
+
+	xbc_node_for_each_array_value(node, "events", anode, p) {
+		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
+			pr_err("String is too long: %s\n", p);
+			continue;
+		}
+
+		if (ftrace_set_clr_event(tr, buf, 1) < 0)
+			pr_err("Failed to enable event: %s\n", p);
+	}
+}
+
+#ifdef CONFIG_KPROBE_EVENTS
+static int __init
+trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
+{
+	struct dynevent_cmd cmd;
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *val;
+	int ret;
+
+	kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
+
+	ret = kprobe_event_gen_cmd_start(&cmd, event, NULL);
+	if (ret)
+		return ret;
+
+	xbc_node_for_each_array_value(node, "probes", anode, val) {
+		ret = kprobe_event_add_field(&cmd, val);
+		if (ret)
+			return ret;
+	}
+
+	ret = kprobe_event_gen_cmd_end(&cmd);
+	if (ret)
+		pr_err("Failed to add probe: %s\n", buf);
+
+	return ret;
+}
+#else
+static inline int __init
+trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
+{
+	pr_err("Kprobe event is not supported.\n");
+	return -ENOTSUPP;
+}
+#endif
+
+#ifdef CONFIG_HIST_TRIGGERS
+static int __init
+trace_boot_add_synth_event(struct xbc_node *node, const char *event)
+{
+	struct dynevent_cmd cmd;
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *p;
+	int ret;
+
+	synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
+
+	ret = synth_event_gen_cmd_start(&cmd, event, NULL);
+	if (ret)
+		return ret;
+
+	xbc_node_for_each_array_value(node, "fields", anode, p) {
+		ret = synth_event_add_field_str(&cmd, p);
+		if (ret)
+			return ret;
+	}
+
+	ret = synth_event_gen_cmd_end(&cmd);
+	if (ret < 0)
+		pr_err("Failed to add synthetic event: %s\n", buf);
+
+	return ret;
+}
+#else
+static inline int __init
+trace_boot_add_synth_event(struct xbc_node *node, const char *event)
+{
+	pr_err("Synthetic event is not supported.\n");
+	return -ENOTSUPP;
+}
+#endif
+
+static void __init
+trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
+			  struct xbc_node *enode)
+{
+	struct trace_event_file *file;
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *p, *group, *event;
+
+	group = xbc_node_get_data(gnode);
+	event = xbc_node_get_data(enode);
+
+	if (!strcmp(group, "kprobes"))
+		if (trace_boot_add_kprobe_event(enode, event) < 0)
+			return;
+	if (!strcmp(group, "synthetic"))
+		if (trace_boot_add_synth_event(enode, event) < 0)
+			return;
+
+	mutex_lock(&event_mutex);
+	file = find_event_file(tr, group, event);
+	if (!file) {
+		pr_err("Failed to find event: %s:%s\n", group, event);
+		goto out;
+	}
+
+	p = xbc_node_find_value(enode, "filter", NULL);
+	if (p && *p != '\0') {
+		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
+			pr_err("filter string is too long: %s\n", p);
+		else if (apply_event_filter(file, buf) < 0)
+			pr_err("Failed to apply filter: %s\n", buf);
+	}
+
+	xbc_node_for_each_array_value(enode, "actions", anode, p) {
+		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
+			pr_err("action string is too long: %s\n", p);
+		else if (trigger_process_regex(file, buf) < 0)
+			pr_err("Failed to apply an action: %s\n", buf);
+	}
+
+	if (xbc_node_find_value(enode, "enable", NULL)) {
+		if (trace_event_enable_disable(file, 1, 0) < 0)
+			pr_err("Failed to enable event node: %s:%s\n",
+				group, event);
+	}
+out:
+	mutex_unlock(&event_mutex);
+}
+
+static void __init
+trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *gnode, *enode;
+
+	node = xbc_node_find_child(node, "event");
+	if (!node)
+		return;
+	/* per-event key starts with "event.GROUP.EVENT" */
+	xbc_node_for_each_child(node, gnode)
+		xbc_node_for_each_child(gnode, enode)
+			trace_boot_init_one_event(tr, gnode, enode);
+}
+#else
+#define trace_boot_enable_events(tr, node) do {} while (0)
+#define trace_boot_init_events(tr, node) do {} while (0)
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static void __init
+trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *anode;
+	const char *p;
+	char *q;
+
+	xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
+		q = kstrdup(p, GFP_KERNEL);
+		if (!q)
+			return;
+		if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
+			pr_err("Failed to add %s to ftrace filter\n", p);
+		else
+			ftrace_filter_param = true;
+		kfree(q);
+	}
+	xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
+		q = kstrdup(p, GFP_KERNEL);
+		if (!q)
+			return;
+		if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
+			pr_err("Failed to add %s to ftrace filter\n", p);
+		else
+			ftrace_filter_param = true;
+		kfree(q);
+	}
+}
+#else
+#define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
+#endif
+
+static void __init
+trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
+{
+	const char *p;
+
+	trace_boot_set_ftrace_filter(tr, node);
+
+	p = xbc_node_find_value(node, "tracer", NULL);
+	if (p && *p != '\0') {
+		if (tracing_set_tracer(tr, p) < 0)
+			pr_err("Failed to set given tracer: %s\n", p);
+	}
+}
+
+static void __init
+trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
+{
+	trace_boot_set_instance_options(tr, node);
+	trace_boot_init_events(tr, node);
+	trace_boot_enable_events(tr, node);
+	trace_boot_enable_tracer(tr, node);
+}
+
+static void __init
+trace_boot_init_instances(struct xbc_node *node)
+{
+	struct xbc_node *inode;
+	struct trace_array *tr;
+	const char *p;
+
+	node = xbc_node_find_child(node, "instance");
+	if (!node)
+		return;
+
+	xbc_node_for_each_child(node, inode) {
+		p = xbc_node_get_data(inode);
+		if (!p || *p == '\0')
+			continue;
+
+		tr = trace_array_get_by_name(p);
+		if (!tr) {
+			pr_err("Failed to get trace instance %s\n", p);
+			continue;
+		}
+		trace_boot_init_one_instance(tr, inode);
+		trace_array_put(tr);
+	}
+}
+
+static int __init trace_boot_init(void)
+{
+	struct xbc_node *trace_node;
+	struct trace_array *tr;
+
+	trace_node = xbc_find_node("ftrace");
+	if (!trace_node)
+		return 0;
+
+	tr = top_trace_array();
+	if (!tr)
+		return 0;
+
+	/* Global trace array is also one instance */
+	trace_boot_init_one_instance(tr, trace_node);
+	trace_boot_init_instances(trace_node);
+
+	return 0;
+}
+
+fs_initcall(trace_boot_init);