From: "Steven Rostedt (VMware)" Add a special type "symbol" that will use %pS to display the field of a function based event. Signed-off-by: Steven Rostedt (VMware) --- Documentation/trace/function-based-events.rst | 26 +++++++++++++++++++++++++- kernel/trace/trace_event_ftrace.c | 13 ++++++++++--- 2 files changed, 35 insertions(+), 4 deletions(-) diff --git a/Documentation/trace/function-based-events.rst b/Documentation/trace/function-based-events.rst index bdb28f433bfb..f18c8f3ef330 100644 --- a/Documentation/trace/function-based-events.rst +++ b/Documentation/trace/function-based-events.rst @@ -98,7 +98,8 @@ as follows: ATOM := 'u8' | 'u16' | 'u32' | 'u64' | 's8' | 's16' | 's32' | 's64' | 'x8' | 'x16' | 'x32' | 'x64' | - 'char' | 'short' | 'int' | 'long' | 'size_t' + 'char' | 'short' | 'int' | 'long' | 'size_t' | + 'symbol' FIELD := | INDEX | OFFSET | OFFSET INDEX @@ -243,3 +244,26 @@ The above will take the parameter value, add it by 4, then index it by two 8 byte words. It's the same in C as: (u64 *)((void *)param + 4)[2] Note: "int skb[32]" is the same as "int skb+4[31]". + + +Symbols (function names) +======================== + +To display kallsyms "%pS" type of output, use the special type "symbol". + +Again, using gdb to find the offset of the "func" field of struct work_struct + +(gdb) printf "%d\n", &((struct work_struct *)0)->func +24 + + Both "symbol func[3]" and "symbol func+24[0]" will work. + + # echo '__queue_work(int cpu, x64 wq, symbol func[3])' > function_events + + # echo 1 > events/functions/__queue_work/enable + # cat trace + bash-1641 [007] d..2 6241.171332: queue_work_on->__queue_work(cpu=128, wq=ffff88011a010e00, func=flush_to_ldisc+0x0/0xa0) + bash-1641 [007] d..2 6241.171460: queue_work_on->__queue_work(cpu=128, wq=ffff88011a010e00, func=flush_to_ldisc+0x0/0xa0) + -0 [000] dNs3 6241.172004: delayed_work_timer_fn->__queue_work(cpu=128, wq=ffff88011a010800, func=vmstat_shepherd+0x0/0xb0) + worker/0:2-1689 [000] d..2 6241.172026: __queue_delayed_work->__queue_work(cpu=7, wq=ffff88011a11da00, func=vmstat_update+0x0/0x70) + -0 [005] d.s3 6241.347996: queue_work_on->__queue_work(cpu=128, wq=ffff88011a011200, func=fb_flashcursor+0x0/0x110 [fb]) diff --git a/kernel/trace/trace_event_ftrace.c b/kernel/trace/trace_event_ftrace.c index 6e48361643c0..1359f714a1b1 100644 --- a/kernel/trace/trace_event_ftrace.c +++ b/kernel/trace/trace_event_ftrace.c @@ -76,6 +76,7 @@ typedef u64 x64; typedef u32 x32; typedef u16 x16; typedef u8 x8; +typedef void * symbol; #define TYPE_TUPLE(type) \ { #type, sizeof(type), is_signed_type(type) } @@ -97,7 +98,8 @@ typedef u8 x8; TYPE_TUPLE(x16), \ TYPE_TUPLE(u8), \ TYPE_TUPLE(s8), \ - TYPE_TUPLE(x8) + TYPE_TUPLE(x8), \ + TYPE_TUPLE(symbol) static struct func_type { char *name; @@ -264,7 +266,7 @@ process_event(struct func_event *fevent, const char *token, enum func_states sta switch (state) { case FUNC_STATE_INIT: unsign = 0; - if (!isalpha(token[0])) + if (!isalpha(token[0]) && token[0] != '_') break; /* Do not allow wild cards */ if (strstr(token, "*") || strstr(token, "?")) @@ -307,7 +309,7 @@ process_event(struct func_event *fevent, const char *token, enum func_states sta return FUNC_STATE_TYPE; case FUNC_STATE_TYPE: - if (!isalpha(token[0])) + if (!isalpha(token[0]) || token[0] == '_') break; if (WARN_ON(!fevent->last_arg)) break; @@ -478,6 +480,11 @@ static void make_fmt(struct func_arg *arg, char *fmt) { int c = 0; + if (arg->func_type == FUNC_TYPE_symbol) { + strcpy(fmt, "%pS"); + return; + } + fmt[c++] = '%'; if (arg->size == 8) { -- 2.15.1