[RFC PATCH v4 21/22] tracing/boot: Add function tracer filter options

Masami Hiramatsu
2019-12-02T10:17:20Z

Add below function-tracer filter options to boot-time tracing.

- ftrace.[instance.INSTANCE.]ftrace.filters
This will take an array of tracing function filter rules

- ftrace.[instance.INSTANCE.]ftrace.notraces
This will take an array of NON-tracing function filter rules

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/trace/trace_boot.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 81d923c16a4d..57274b9b3718 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -244,11 +244,51 @@ trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
#define trace_boot_init_events(tr, node) do {} while (0)
#endif

+#ifdef CONFIG_FUNCTION_TRACER
+extern bool ftrace_filter_param __initdata;
+extern int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+ int len, int reset);
+extern int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+ int len, int reset);
+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)