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authorSteven Rostedt (Google)2023-02-07 12:28:50 -0500
committerSteven Rostedt (Google)2023-02-07 12:49:56 -0500
commitcb1f98c5e5742273bca39410d504430793ab701a (patch)
tree49b548d0bc0d127bb822339ea39266d9d220db3f /kernel/trace
parent9971c3f944489ff7aacb9d25e0cde841a5f6018a (diff)
tracing: Add creation of instances at boot command line
Add kernel command line to add tracing instances. This only creates instances at boot but still does not enable any events to them. Later changes will extend this command line to add enabling of events, filters, and triggers. As well as possibly redirecting trace_printk()! Link: https://lkml.kernel.org/r/20230207173026.186210158@goodmis.org Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Ross Zwisler <zwisler@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b90eecd27dfc..863716fcca49 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -49,6 +49,8 @@
#include <linux/irq_work.h>
#include <linux/workqueue.h>
+#include <asm/setup.h> /* COMMAND_LINE_SIZE */
+
#include "trace.h"
#include "trace_output.h"
@@ -186,6 +188,9 @@ static char *default_bootup_tracer;
static bool allocate_snapshot;
static bool snapshot_at_boot;
+static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
+static int boot_instance_index;
+
static int __init set_cmdline_ftrace(char *str)
{
strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
@@ -239,6 +244,23 @@ static int __init boot_snapshot(char *str)
__setup("ftrace_boot_snapshot", boot_snapshot);
+static int __init boot_instance(char *str)
+{
+ char *slot = boot_instance_info + boot_instance_index;
+ int left = sizeof(boot_instance_info) - boot_instance_index;
+ int ret;
+
+ if (strlen(str) >= left)
+ return -1;
+
+ ret = snprintf(slot, left, "%s\t", str);
+ boot_instance_index += ret;
+
+ return 1;
+}
+__setup("trace_instance=", boot_instance);
+
+
static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
static int __init set_trace_boot_options(char *str)
@@ -10144,6 +10166,31 @@ out:
return ret;
}
+__init static void enable_instances(void)
+{
+ struct trace_array *tr;
+ char *curr_str;
+ char *str;
+ char *tok;
+
+ /* A tab is always appended */
+ boot_instance_info[boot_instance_index - 1] = '\0';
+ str = boot_instance_info;
+
+ while ((curr_str = strsep(&str, "\t"))) {
+
+ tok = strsep(&curr_str, ",");
+
+ tr = trace_array_get_by_name(tok);
+ if (!tr) {
+ pr_warn("Failed to create instance buffer %s\n", curr_str);
+ continue;
+ }
+ /* Allow user space to delete it */
+ trace_array_put(tr);
+ }
+}
+
__init static int tracer_alloc_buffers(void)
{
int ring_buf_size;
@@ -10302,6 +10349,9 @@ void __init early_trace_init(void)
void __init trace_init(void)
{
trace_event_init();
+
+ if (boot_instance_index)
+ enable_instances();
}
__init static void clear_boot_tracer(void)