This patch introduces 'func_ptrace' option, now available in /sys/kernel/debug/tracing/options when function tracer is selected.
The patch also adds some tiny code that calls back to pstore to record the trace. The callback is no-op when PSTORE=n.
Signed-off-by: Anton Vorontsov anton.vorontsov@linaro.org --- kernel/trace/trace_functions.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index c7b0c6a..13770ab 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -13,6 +13,7 @@ #include <linux/debugfs.h> #include <linux/uaccess.h> #include <linux/ftrace.h> +#include <linux/pstore.h> #include <linux/fs.h>
#include "trace.h" @@ -74,6 +75,14 @@ function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip) preempt_enable_notrace(); }
+/* Our two options */ +enum { + TRACE_FUNC_OPT_STACK = 0x1, + TRACE_FUNC_OPT_PSTORE = 0x2, +}; + +static struct tracer_flags func_flags; + static void function_trace_call(unsigned long ip, unsigned long parent_ip) { @@ -97,6 +106,12 @@ function_trace_call(unsigned long ip, unsigned long parent_ip) disabled = atomic_inc_return(&data->disabled);
if (likely(disabled == 1)) { + /* + * So far tracing doesn't support multiple buffers, so + * we make an explicit call for now. + */ + if (unlikely(func_flags.val & TRACE_FUNC_OPT_PSTORE)) + pstore_ftrace_call(ip, parent_ip); pc = preempt_count(); trace_function(tr, ip, parent_ip, flags, pc); } @@ -158,15 +173,13 @@ static struct ftrace_ops trace_stack_ops __read_mostly = .flags = FTRACE_OPS_FL_GLOBAL, };
-/* Our two options */ -enum { - TRACE_FUNC_OPT_STACK = 0x1, -}; - static struct tracer_opt func_opts[] = { #ifdef CONFIG_STACKTRACE { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) }, #endif +#ifdef CONFIG_PSTORE_FTRACE + { TRACER_OPT(func_pstore, TRACE_FUNC_OPT_PSTORE) }, +#endif { } /* Always set a last empty entry */ };
@@ -218,6 +231,8 @@ static int func_set_flag(u32 old_flags, u32 bit, int set) }
return 0; + } else if (bit == TRACE_FUNC_OPT_PSTORE) { + return 0; }
return -EINVAL;