diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 07df952a0d7f..6cc696edf24a 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -690,6 +690,10 @@ struct syscall_arg_fmt { static struct syscall_fmt { const char *name; const char *alias; + struct { + const char *sys_enter, + *sys_exit; + } bpf_prog_name; struct syscall_arg_fmt arg[6]; u8 nr_args; bool errpid; @@ -823,6 +827,7 @@ static struct syscall_fmt { { .name = "newfstatat", .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, }, }, { .name = "open", + .bpf_prog_name = { .sys_enter = "!syscalls:sys_enter_open", }, .arg = { [1] = { .scnprintf = SCA_OPEN_FLAGS, /* flags */ }, }, }, { .name = "open_by_handle_at", .arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ }, @@ -967,6 +972,10 @@ struct syscall { struct tep_event *tp_format; int nr_args; int args_size; + struct { + struct bpf_program *sys_enter, + *sys_exit; + } bpf_prog; bool is_exit; bool is_open; struct tep_format_field *args; @@ -2742,6 +2751,39 @@ static struct bpf_program *trace__find_bpf_program_by_title(struct trace *trace, return bpf_object__find_program_by_title(trace->bpf_obj, name); } +static struct bpf_program *trace__find_syscall_bpf_prog(struct trace *trace, struct syscall *sc, + const char *prog_name, const char *type) +{ + struct bpf_program *prog; + + if (prog_name == NULL) + goto out_unaugmented; + + prog = trace__find_bpf_program_by_title(trace, prog_name); + if (prog != NULL) + return prog; + + pr_debug("Couldn't find BPF prog \"%s\" to associate with syscalls:sys_%s_%s, not augmenting it\n", + prog_name, type, sc->name); +out_unaugmented: + return trace->syscalls.unaugmented_prog; +} + +static void trace__init_syscall_bpf_progs(struct trace *trace, int id) +{ + struct syscall *sc = trace__syscall_info(trace, NULL, id); + + if (sc == NULL) + return; + + if (sc->fmt != NULL) { + sc->bpf_prog.sys_enter = trace__find_syscall_bpf_prog(trace, sc, sc->fmt->bpf_prog_name.sys_enter, "enter"); + sc->bpf_prog.sys_exit = trace__find_syscall_bpf_prog(trace, sc, sc->fmt->bpf_prog_name.sys_exit, "exit"); + } else { + sc->bpf_prog.sys_enter = sc->bpf_prog.sys_exit = trace->syscalls.unaugmented_prog; + } +} + static void trace__init_bpf_map_syscall_args(struct trace *trace, int id, struct bpf_map_syscall_entry *entry) { struct syscall *sc = trace__syscall_info(trace, NULL, id); @@ -2773,8 +2815,10 @@ static int trace__set_ev_qualifier_bpf_filter(struct trace *trace) for (i = 0; i < trace->ev_qualifier_ids.nr; ++i) { int key = trace->ev_qualifier_ids.entries[i]; - if (value.enabled) + if (value.enabled) { trace__init_bpf_map_syscall_args(trace, key, &value); + trace__init_syscall_bpf_progs(trace, key); + } err = bpf_map_update_elem(fd, &key, &value, BPF_EXIST); if (err) @@ -2793,8 +2837,10 @@ static int __trace__init_syscalls_bpf_map(struct trace *trace, bool enabled) int err = 0, key; for (key = 0; key < trace->sctbl->syscalls.nr_entries; ++key) { - if (enabled) + if (enabled) { trace__init_bpf_map_syscall_args(trace, key, &value); + trace__init_syscall_bpf_progs(trace, key); + } err = bpf_map_update_elem(fd, &key, &value, BPF_ANY); if (err) diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c index 48a536b1be6d..66b33b299349 100644 --- a/tools/perf/examples/bpf/augmented_raw_syscalls.c +++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c @@ -94,6 +94,29 @@ int syscall_unaugmented(struct syscall_enter_args *args) return 1; } +/* + * This will be tail_called from SEC("raw_syscalls:sys_enter"), so will find in + * augmented_filename_map what was read by that raw_syscalls:sys_enter and go + * on from there, reading the first syscall arg as a string, i.e. open's + * filename. + */ +SEC("!syscalls:sys_enter_open") +int sys_enter_open(struct syscall_enter_args *args) +{ + int key = 0; + struct augmented_args_filename *augmented_args = bpf_map_lookup_elem(&augmented_filename_map, &key); + const void *filename_arg = (const void *)args->args[0]; + unsigned int len = sizeof(augmented_args->args); + + if (augmented_args == NULL) + return 1; /* Failure: don't filter */ + + len += augmented_filename__read(&augmented_args->filename, filename_arg, sizeof(augmented_args->filename.value)); + + /* If perf_event_output fails, return non-zero so that it gets recorded unaugmented */ + return perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, augmented_args, len); +} + SEC("raw_syscalls:sys_enter") int sys_enter(struct syscall_enter_args *args) {