Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752952AbdLFWsT (ORCPT ); Wed, 6 Dec 2017 17:48:19 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:46130 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752598AbdLFWpX (ORCPT ); Wed, 6 Dec 2017 17:45:23 -0500 Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig102.frc2.facebook.com To: , , , , , , CC: , Song Liu Smtp-Origin-Cluster: frc2c02 Subject: [PATCH v5 3/6] perf: implement pmu perf_kprobe Date: Wed, 6 Dec 2017 14:45:15 -0800 Message-ID: <20171206224518.3598254-6-songliubraving@fb.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20171206224518.3598254-1-songliubraving@fb.com> References: <20171206224518.3598254-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-12-06_08:,, signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10571 Lines: 365 A new pmu, perf_kprobe is added. Based attr from perf_event_open(), perf_kprobe creates a kprobe (or kretprobe) for the perf_event. This kprobe is private to this perf_event, and thus not added to global lists, and not available in tracefs. Two functions, create_local_trace_kprobe() and destroy_local_trace_kprobe() are added to created and destroy these local trace_kprobe. Signed-off-by: Song Liu Reviewed-by: Yonghong Song Reviewed-by: Josef Bacik --- include/linux/trace_events.h | 4 ++ kernel/events/core.c | 87 ++++++++++++++++++++++++++++++++++++++- kernel/trace/trace_event_perf.c | 49 ++++++++++++++++++++++ kernel/trace/trace_kprobe.c | 91 +++++++++++++++++++++++++++++++++++++---- kernel/trace/trace_probe.h | 7 ++++ 5 files changed, 228 insertions(+), 10 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 2bcb4dc..1cfb0a4 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -494,6 +494,10 @@ extern int perf_trace_init(struct perf_event *event); extern void perf_trace_destroy(struct perf_event *event); extern int perf_trace_add(struct perf_event *event, int flags); extern void perf_trace_del(struct perf_event *event, int flags); +#ifdef CONFIG_KPROBE_EVENTS +extern int perf_kprobe_init(struct perf_event *event, bool is_retprobe); +extern void perf_kprobe_destroy(struct perf_event *event); +#endif extern int ftrace_profile_set_filter(struct perf_event *event, int event_id, char *filter_str); extern void ftrace_profile_free_filter(struct perf_event *event); diff --git a/kernel/events/core.c b/kernel/events/core.c index 494eca1..f518214 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7981,9 +7981,92 @@ static struct pmu perf_tracepoint = { .read = perf_swevent_read, }; +/* + * Flags in config, used by dynamic PMU kprobe and uprobe + * The flags should match following PMU_FORMAT_ATTR(). + * + * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe + * if not set, create kprobe/uprobe + */ +enum perf_probe_config { + PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ +}; + +PMU_FORMAT_ATTR(retprobe, "config:0"); + +static struct attribute *probe_attrs[] = { + &format_attr_retprobe.attr, + NULL, +}; + +static struct attribute_group probe_format_group = { + .name = "format", + .attrs = probe_attrs, +}; + +static const struct attribute_group *probe_attr_groups[] = { + &probe_format_group, + NULL, +}; + +#ifdef CONFIG_KPROBE_EVENTS +static int perf_kprobe_event_init(struct perf_event *event); +static struct pmu perf_kprobe = { + .task_ctx_nr = perf_sw_context, + .event_init = perf_kprobe_event_init, + .add = perf_trace_add, + .del = perf_trace_del, + .start = perf_swevent_start, + .stop = perf_swevent_stop, + .read = perf_swevent_read, + .attr_groups = probe_attr_groups, +}; + +static int perf_kprobe_event_init(struct perf_event *event) +{ + int err; + bool is_retprobe; + + if (event->attr.type != perf_kprobe.type) + return -ENOENT; + /* + * no branch sampling for probe events + */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; + err = perf_kprobe_init(event, is_retprobe); + if (err) + return err; + + event->destroy = perf_kprobe_destroy; + + return 0; +} +#endif /* CONFIG_KPROBE_EVENTS */ + +/* + * returns true if the event is a tracepoint, or a kprobe/upprobe created + * with perf_event_open() + */ +static inline bool perf_event_is_tracing(struct perf_event *event) +{ + if (event->attr.type == PERF_TYPE_TRACEPOINT) + return true; +#ifdef CONFIG_KPROBE_EVENTS + if (event->pmu == &perf_kprobe) + return true; +#endif + return false; +} + static inline void perf_tp_register(void) { perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); +#ifdef CONFIG_KPROBE_EVENTS + perf_pmu_register(&perf_kprobe, "kprobe", -1); +#endif } static void perf_event_free_filter(struct perf_event *event) @@ -8065,7 +8148,7 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) bool is_kprobe, is_tracepoint, is_syscall_tp; struct bpf_prog *prog; - if (event->attr.type != PERF_TYPE_TRACEPOINT) + if (!perf_event_is_tracing(event)) return perf_event_set_bpf_handler(event, prog_fd); if (event->tp_event->prog) @@ -8537,7 +8620,7 @@ static int perf_event_set_filter(struct perf_event *event, void __user *arg) char *filter_str; int ret = -EINVAL; - if ((event->attr.type != PERF_TYPE_TRACEPOINT || + if ((!perf_event_is_tracing(event) || !IS_ENABLED(CONFIG_EVENT_TRACING)) && !has_addr_filter(event)) return -EINVAL; diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 13ba2d3..7f1cc45 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -8,6 +8,7 @@ #include #include #include "trace.h" +#include "trace_probe.h" static char __percpu *perf_trace_buf[PERF_NR_CONTEXTS]; @@ -237,6 +238,54 @@ void perf_trace_destroy(struct perf_event *p_event) mutex_unlock(&event_mutex); } +#ifdef CONFIG_KPROBE_EVENTS +int perf_kprobe_init(struct perf_event *p_event, bool is_retprobe) +{ + int ret; + char *func = NULL; + struct trace_event_call *tp_event; + + if (p_event->attr.kprobe_func) { + func = kzalloc(KSYM_NAME_LEN, GFP_KERNEL); + if (!func) + return -ENOMEM; + ret = strncpy_from_user( + func, u64_to_user_ptr(p_event->attr.kprobe_func), + KSYM_NAME_LEN); + if (ret < 0) + goto out; + + if (func[0] == '\0') { + kfree(func); + func = NULL; + } + } + + tp_event = create_local_trace_kprobe( + func, (void *)(unsigned long)(p_event->attr.kprobe_addr), + p_event->attr.probe_offset, is_retprobe); + if (IS_ERR(tp_event)) { + ret = PTR_ERR(tp_event); + goto out; + } + + ret = perf_trace_event_init(tp_event, p_event); + if (ret) + destroy_local_trace_kprobe(tp_event); +out: + kfree(func); + return ret; +} + +void perf_kprobe_destroy(struct perf_event *p_event) +{ + perf_trace_event_close(p_event); + perf_trace_event_unreg(p_event); + + destroy_local_trace_kprobe(p_event->tp_event); +} +#endif /* CONFIG_KPROBE_EVENTS */ + int perf_trace_add(struct perf_event *p_event, int flags) { struct trace_event_call *tp_event = p_event->tp_event; diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 8a907e1..16b334a 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -438,6 +438,14 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) disable_kprobe(&tk->rp.kp); wait = 1; } + + /* + * if tk is not added to any list, it must be a local trace_kprobe + * created with perf_event_open. We don't need to wait for these + * trace_kprobes + */ + if (list_empty(&tk->list)) + wait = 0; out: if (wait) { /* @@ -1315,12 +1323,9 @@ static struct trace_event_functions kprobe_funcs = { .trace = print_kprobe_event }; -static int register_kprobe_event(struct trace_kprobe *tk) +static inline void init_trace_event_call(struct trace_kprobe *tk, + struct trace_event_call *call) { - struct trace_event_call *call = &tk->tp.call; - int ret; - - /* Initialize trace_event_call */ INIT_LIST_HEAD(&call->class->fields); if (trace_kprobe_is_return(tk)) { call->event.funcs = &kretprobe_funcs; @@ -1329,6 +1334,19 @@ static int register_kprobe_event(struct trace_kprobe *tk) call->event.funcs = &kprobe_funcs; call->class->define_fields = kprobe_event_define_fields; } + + call->flags = TRACE_EVENT_FL_KPROBE; + call->class->reg = kprobe_register; + call->data = tk; +} + +static int register_kprobe_event(struct trace_kprobe *tk) +{ + struct trace_event_call *call = &tk->tp.call; + int ret = 0; + + init_trace_event_call(tk, call); + if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) return -ENOMEM; ret = register_trace_event(&call->event); @@ -1336,9 +1354,6 @@ static int register_kprobe_event(struct trace_kprobe *tk) kfree(call->print_fmt); return -ENODEV; } - call->flags = TRACE_EVENT_FL_KPROBE; - call->class->reg = kprobe_register; - call->data = tk; ret = trace_add_event_call(call); if (ret) { pr_info("Failed to register kprobe event: %s\n", @@ -1360,6 +1375,66 @@ static int unregister_kprobe_event(struct trace_kprobe *tk) return ret; } +#ifdef CONFIG_PERF_EVENTS +/* create a trace_kprobe, but don't add it to global lists */ +struct trace_event_call * +create_local_trace_kprobe(char *func, void *addr, unsigned long offs, + bool is_return) +{ + struct trace_kprobe *tk; + int ret; + char *event; + + /* + * local trace_kprobes are not added to probe_list, so they are never + * searched in find_trace_kprobe(). Therefore, there is no concern of + * duplicated name here. + */ + event = func ? func : "DUMMY_EVENT"; + + tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, + offs, 0 /* maxactive */, 0 /* nargs */, + is_return); + + if (IS_ERR(tk)) { + pr_info("Failed to allocate trace_probe.(%d)\n", + (int)PTR_ERR(tk)); + return ERR_CAST(tk); + } + + init_trace_event_call(tk, &tk->tp.call); + + if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) { + ret = -ENOMEM; + goto error; + } + + ret = __register_trace_kprobe(tk); + if (ret < 0) + goto error; + + return &tk->tp.call; +error: + free_trace_kprobe(tk); + return ERR_PTR(ret); +} + +void destroy_local_trace_kprobe(struct trace_event_call *event_call) +{ + struct trace_kprobe *tk; + + tk = container_of(event_call, struct trace_kprobe, tp.call); + + if (trace_probe_is_enabled(&tk->tp)) { + WARN_ON(1); + return; + } + + __unregister_trace_kprobe(tk); + free_trace_kprobe(tk); +} +#endif /* CONFIG_PERF_EVENTS */ + /* Make a tracefs interface for controlling probe points */ static __init int init_kprobe_trace(void) { diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 903273c..910ae1b 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -411,3 +411,10 @@ store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs, } extern int set_print_fmt(struct trace_probe *tp, bool is_return); + +#ifdef CONFIG_PERF_EVENTS +extern struct trace_event_call * +create_local_trace_kprobe(char *func, void *addr, unsigned long offs, + bool is_return); +extern void destroy_local_trace_kprobe(struct trace_event_call *event_call); +#endif -- 2.9.5