From 7a983a0fe2a29ec849f6748d6bd86904d6e88eea Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 20 Aug 2018 17:58:17 -0300 Subject: [PATCH] perf trace: Pass augmented args to the arg formatters when available If the tracepoint payload is bigger than what a syscall expected from what is in its format file in tracefs, then that will be used as augmented args, i.e. the expansion of syscall arg pointers, with things like a filename, structs, etc. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-bsbqx7xi2ot4q9bf570f7tqs@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-trace.c | 28 ++++++++++++++++++++++------ tools/perf/trace/beauty/beauty.h | 29 +++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+), 6 deletions(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 22ab8e67c760..7deae6c8cb25 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -856,10 +856,12 @@ static struct syscall_fmt *syscall_fmt__find(const char *name) /* * is_exit: is this "exit" or "exit_group"? * is_open: is this "open" or "openat"? To associate the fd returned in sys_exit with the pathname in sys_enter. + * args_size: sum of the sizes of the syscall arguments, anything after that is augmented stuff: pathname for openat, etc. */ struct syscall { struct event_format *tp_format; int nr_args; + int args_size; bool is_exit; bool is_open; struct format_field *args; @@ -1258,10 +1260,12 @@ static int syscall__alloc_arg_fmts(struct syscall *sc, int nr_args) static int syscall__set_arg_fmts(struct syscall *sc) { - struct format_field *field; + struct format_field *field, *last_field = NULL; int idx = 0, len; for (field = sc->args; field; field = field->next, ++idx) { + last_field = field; + if (sc->fmt && sc->fmt->arg[idx].scnprintf) continue; @@ -1292,6 +1296,9 @@ static int syscall__set_arg_fmts(struct syscall *sc) } } + if (last_field) + sc->args_size = last_field->offset + last_field->size; + return 0; } @@ -1472,14 +1479,18 @@ static size_t syscall__scnprintf_val(struct syscall *sc, char *bf, size_t size, } static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size, - unsigned char *args, struct trace *trace, - struct thread *thread) + unsigned char *args, void *augmented_args, int augmented_args_size, + struct trace *trace, struct thread *thread) { size_t printed = 0; unsigned long val; u8 bit = 1; struct syscall_arg arg = { .args = args, + .augmented = { + .size = augmented_args_size, + .args = augmented_args, + }, .idx = 0, .mask = 0, .trace = trace, @@ -1692,7 +1703,7 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel, printed += scnprintf(msg + printed, trace__entry_str_size - printed, "%s(", sc->name); printed += syscall__scnprintf_args(sc, msg + printed, trace__entry_str_size - printed, - args, trace, thread); + args, NULL, 0, trace, thread); if (sc->is_exit) { if (!(trace->duration_filter || trace->summary_only || trace->failure_only || trace->min_stack)) { @@ -1723,7 +1734,8 @@ static int trace__fprintf_sys_enter(struct trace *trace, struct perf_evsel *evse int id = perf_evsel__sc_tp_uint(evsel, id, sample), err = -1; struct syscall *sc = trace__syscall_info(trace, evsel, id); char msg[1024]; - void *args; + void *args, *augmented_args = NULL; + int augmented_args_size; if (sc == NULL) return -1; @@ -1738,7 +1750,11 @@ static int trace__fprintf_sys_enter(struct trace *trace, struct perf_evsel *evse goto out_put; args = perf_evsel__sc_tp_ptr(evsel, args, sample); - syscall__scnprintf_args(sc, msg, sizeof(msg), args, trace, thread); + augmented_args_size = sample->raw_size - sc->args_size; + if (augmented_args_size > 0) + augmented_args = sample->raw_data + sc->args_size; + + syscall__scnprintf_args(sc, msg, sizeof(msg), args, augmented_args, augmented_args_size, trace, thread); fprintf(trace->output, "%s", msg); err = 0; out_put: diff --git a/tools/perf/trace/beauty/beauty.h b/tools/perf/trace/beauty/beauty.h index 9615af5d412b..6ca044d3d851 100644 --- a/tools/perf/trace/beauty/beauty.h +++ b/tools/perf/trace/beauty/beauty.h @@ -30,9 +30,34 @@ struct thread; size_t pid__scnprintf_fd(struct trace *trace, pid_t pid, int fd, char *bf, size_t size); +/** + * augmented_arg: extra payload for syscall pointer arguments + + * If perf_sample->raw_size is more than what a syscall sys_enter_FOO puts, + * then its the arguments contents, so that we can show more than just a + * pointer. This will be done initially with eBPF, the start of that is at the + * tools/perf/examples/bpf/augmented_syscalls.c example for the openat, but + * will eventually be done automagically caching the running kernel tracefs + * events data into an eBPF C script, that then gets compiled and its .o file + * cached for subsequent use. For char pointers like the ones for 'open' like + * syscalls its easy, for the rest we should use DWARF or better, BTF, much + * more compact. + * + * @size: 8 if all we need is an integer, otherwise all of the augmented arg. + * @int_arg: will be used for integer like pointer contents, like 'accept's 'upeer_addrlen' + * @value: u64 aligned, for structs, pathnames + */ +struct augmented_arg { + int size; + int int_arg; + u64 value[]; +}; + /** * @val: value of syscall argument being formatted * @args: All the args, use syscall_args__val(arg, nth) to access one + * @augmented_args: Extra data that can be collected, for instance, with eBPF for expanding the pathname for open, etc + * @augmented_args_size: augmented_args total payload size * @thread: tid state (maps, pid, tid, etc) * @trace: 'perf trace' internals: all threads, etc * @parm: private area, may be an strarray, for instance @@ -43,6 +68,10 @@ size_t pid__scnprintf_fd(struct trace *trace, pid_t pid, int fd, char *bf, size_ struct syscall_arg { unsigned long val; unsigned char *args; + struct { + struct augmented_arg *args; + int size; + } augmented; struct thread *thread; struct trace *trace; void *parm; -- 2.30.2