lkml.org 
[lkml]   [2017]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v2 4/6] perf: implement support of PERF_TYPE_UPROBE
    Date
    This patch adds perf_uprobe support with similar pattern as previous
    patch (for kprobe).

    Two functions, create_local_trace_uprobe() and
    destroy_local_trace_uprobe(), are created so a uprobe can be created
    and attached to the file descriptor created by perf_event_open().

    Signed-off-by: Song Liu <songliubraving@fb.com>
    Reviewed-by: Yonghong Song <yhs@fb.com>
    Reviewed-by: Josef Bacik <jbacik@fb.com>
    ---
    include/linux/trace_events.h | 2 +
    kernel/events/core.c | 39 +++++++++++++++++-
    kernel/trace/trace_event_perf.c | 58 ++++++++++++++++++++++++++
    kernel/trace/trace_probe.h | 4 ++
    kernel/trace/trace_uprobe.c | 90 ++++++++++++++++++++++++++++++++++++-----
    5 files changed, 181 insertions(+), 12 deletions(-)

    diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
    index 51f748c9..9272fa6 100644
    --- a/include/linux/trace_events.h
    +++ b/include/linux/trace_events.h
    @@ -496,6 +496,8 @@ extern int perf_trace_add(struct perf_event *event, int flags);
    extern void perf_trace_del(struct perf_event *event, int flags);
    extern int perf_kprobe_init(struct perf_event *event);
    extern void perf_kprobe_destroy(struct perf_event *event);
    +extern int perf_uprobe_init(struct perf_event *event);
    +extern void perf_uprobe_destroy(struct perf_event *event);
    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 daa6e0a..b566a53 100644
    --- a/kernel/events/core.c
    +++ b/kernel/events/core.c
    @@ -7992,6 +7992,28 @@ static int perf_kprobe_event_init(struct perf_event *event)
    return 0;
    }

    +static int perf_uprobe_event_init(struct perf_event *event)
    +{
    + int err;
    +
    + if (event->attr.type != PERF_TYPE_UPROBE)
    + return -ENOENT;
    +
    + /*
    + * no branch sampling for probe events
    + */
    + if (has_branch_stack(event))
    + return -EOPNOTSUPP;
    +
    + err = perf_uprobe_init(event);
    + if (err)
    + return err;
    +
    + event->destroy = perf_uprobe_destroy;
    +
    + return 0;
    +}
    +
    static struct pmu perf_tracepoint = {
    .task_ctx_nr = perf_sw_context,

    @@ -8013,10 +8035,21 @@ static struct pmu perf_kprobe = {
    .read = perf_swevent_read,
    };

    +static struct pmu perf_uprobe = {
    + .task_ctx_nr = perf_sw_context,
    + .event_init = perf_uprobe_event_init,
    + .add = perf_trace_add,
    + .del = perf_trace_del,
    + .start = perf_swevent_start,
    + .stop = perf_swevent_stop,
    + .read = perf_swevent_read,
    +};
    +
    static inline void perf_tp_register(void)
    {
    perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
    perf_pmu_register(&perf_kprobe, "kprobe", PERF_TYPE_KPROBE);
    + perf_pmu_register(&perf_uprobe, "uprobe", PERF_TYPE_UPROBE);
    }

    static void perf_event_free_filter(struct perf_event *event)
    @@ -8099,7 +8132,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
    struct bpf_prog *prog;

    if (event->attr.type != PERF_TYPE_TRACEPOINT &&
    - event->attr.type != PERF_TYPE_KPROBE)
    + event->attr.type != PERF_TYPE_KPROBE &&
    + event->attr.type != PERF_TYPE_UPROBE)
    return perf_event_set_bpf_handler(event, prog_fd);

    if (event->tp_event->prog)
    @@ -8572,7 +8606,8 @@ static int perf_event_set_filter(struct perf_event *event, void __user *arg)
    int ret = -EINVAL;

    if (((event->attr.type != PERF_TYPE_TRACEPOINT &&
    - event->attr.type != PERF_TYPE_KPROBE) ||
    + event->attr.type != PERF_TYPE_KPROBE &&
    + event->attr.type != PERF_TYPE_UPROBE) ||
    !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 7cf0d99..1b97ea2 100644
    --- a/kernel/trace/trace_event_perf.c
    +++ b/kernel/trace/trace_event_perf.c
    @@ -272,6 +272,52 @@ int perf_kprobe_init(struct perf_event *p_event)
    #endif /* CONFIG_KPROBE_EVENTS */
    }

    +int perf_uprobe_init(struct perf_event *p_event)
    +{
    + int ret;
    + char *path = NULL;
    + struct trace_event_call *tp_event;
    +
    +#ifdef CONFIG_UPROBE_EVENTS
    + if (!p_event->attr.uprobe_path)
    + return -EINVAL;
    + path = kzalloc(PATH_MAX, GFP_KERNEL);
    + if (!path)
    + return -ENOMEM;
    + ret = strncpy_from_user(
    + path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);
    + if (ret < 0)
    + goto out;
    + if (path[0] == '\0') {
    + ret = -EINVAL;
    + goto out;
    + }
    +
    + tp_event = create_local_trace_uprobe(
    + path, p_event->attr.probe_offset, p_event->attr.config != 0);
    + if (IS_ERR(tp_event)) {
    + ret = PTR_ERR(tp_event);
    + goto out;
    + }
    +
    + /*
    + * local trace_uprobe need to hold event_mutex to call
    + * uprobe_buffer_enable() and uprobe_buffer_disable().
    + * event_mutex is not required for local trace_kprobes.
    + */
    + mutex_lock(&event_mutex);
    + ret = perf_trace_event_init(tp_event, p_event);
    + if (ret)
    + destroy_local_trace_uprobe(tp_event);
    + mutex_unlock(&event_mutex);
    +out:
    + kfree(path);
    + return ret;
    +#else
    + return -EOPNOTSUPP;
    +#endif /* CONFIG_UPROBE_EVENTS */
    +}
    +
    void perf_trace_destroy(struct perf_event *p_event)
    {
    mutex_lock(&event_mutex);
    @@ -290,6 +336,18 @@ void perf_kprobe_destroy(struct perf_event *p_event)
    #endif
    }

    +void perf_uprobe_destroy(struct perf_event *p_event)
    +{
    + mutex_lock(&event_mutex);
    + perf_trace_event_close(p_event);
    + perf_trace_event_unreg(p_event);
    + mutex_unlock(&event_mutex);
    +
    +#ifdef CONFIG_UPROBE_EVENTS
    + destroy_local_trace_uprobe(p_event->tp_event);
    +#endif
    +}
    +
    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_probe.h b/kernel/trace/trace_probe.h
    index 910ae1b..86b5925 100644
    --- a/kernel/trace/trace_probe.h
    +++ b/kernel/trace/trace_probe.h
    @@ -417,4 +417,8 @@ 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);
    +
    +extern struct trace_event_call *
    +create_local_trace_uprobe(char *name, unsigned long offs, bool is_return);
    +extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);
    #endif
    diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
    index 4525e02..4d805d2 100644
    --- a/kernel/trace/trace_uprobe.c
    +++ b/kernel/trace/trace_uprobe.c
    @@ -31,8 +31,8 @@
    #define UPROBE_EVENT_SYSTEM "uprobes"

    struct uprobe_trace_entry_head {
    - struct trace_entry ent;
    - unsigned long vaddr[];
    + struct trace_entry ent;
    + unsigned long vaddr[];
    };

    #define SIZEOF_TRACE_ENTRY(is_return) \
    @@ -1293,16 +1293,25 @@ static struct trace_event_functions uprobe_funcs = {
    .trace = print_uprobe_event
    };

    -static int register_uprobe_event(struct trace_uprobe *tu)
    +static inline void init_trace_event_call(struct trace_uprobe *tu,
    + struct trace_event_call *call)
    {
    - struct trace_event_call *call = &tu->tp.call;
    - int ret;
    -
    - /* Initialize trace_event_call */
    INIT_LIST_HEAD(&call->class->fields);
    call->event.funcs = &uprobe_funcs;
    call->class->define_fields = uprobe_event_define_fields;

    + call->flags = TRACE_EVENT_FL_UPROBE;
    + call->class->reg = trace_uprobe_register;
    + call->data = tu;
    +}
    +
    +static int register_uprobe_event(struct trace_uprobe *tu)
    +{
    + struct trace_event_call *call = &tu->tp.call;
    + int ret = 0;
    +
    + init_trace_event_call(tu, call);
    +
    if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
    return -ENOMEM;

    @@ -1312,9 +1321,6 @@ static int register_uprobe_event(struct trace_uprobe *tu)
    return -ENODEV;
    }

    - call->flags = TRACE_EVENT_FL_UPROBE;
    - call->class->reg = trace_uprobe_register;
    - call->data = tu;
    ret = trace_add_event_call(call);

    if (ret) {
    @@ -1340,6 +1346,70 @@ static int unregister_uprobe_event(struct trace_uprobe *tu)
    return 0;
    }

    +#ifdef CONFIG_PERF_EVENTS
    +struct trace_event_call *
    +create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)
    +{
    + struct trace_uprobe *tu;
    + struct inode *inode;
    + struct path path;
    + int ret;
    +
    + ret = kern_path(name, LOOKUP_FOLLOW, &path);
    + if (ret)
    + return ERR_PTR(ret);
    +
    + inode = igrab(d_inode(path.dentry));
    + path_put(&path);
    +
    + if (!inode || !S_ISREG(inode->i_mode)) {
    + iput(inode);
    + return ERR_PTR(-EINVAL);
    + }
    +
    + /*
    + * 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 "DUMMY_EVENT" here.
    + */
    + tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
    + is_return);
    +
    + if (IS_ERR(tu)) {
    + pr_info("Failed to allocate trace_uprobe.(%d)\n",
    + (int)PTR_ERR(tu));
    + return ERR_CAST(tu);
    + }
    +
    + tu->offset = offs;
    + tu->inode = inode;
    + tu->filename = kstrdup(name, GFP_KERNEL);
    + init_trace_event_call(tu, &tu->tp.call);
    +
    + if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
    + ret = -ENOMEM;
    + goto error;
    + }
    +
    + return &tu->tp.call;
    +error:
    + free_trace_uprobe(tu);
    + return ERR_PTR(ret);
    +}
    +
    +void destroy_local_trace_uprobe(struct trace_event_call *event_call)
    +{
    + struct trace_uprobe *tu;
    +
    + tu = container_of(event_call, struct trace_uprobe, tp.call);
    +
    + kfree(tu->tp.call.print_fmt);
    + tu->tp.call.print_fmt = NULL;
    +
    + free_trace_uprobe(tu);
    +}
    +#endif /* CONFIG_PERF_EVENTS */
    +
    /* Make a trace interface for controling probe points */
    static __init int init_uprobe_trace(void)
    {
    --
    2.9.5
    \
     
     \ /
      Last update: 2017-11-30 02:46    [W:3.473 / U:0.468 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site