tracing, perf: Implement BPF programs attached to uprobes

By copying BPF related operation to uprobe processing path, this patch
allow users attach BPF programs to uprobes like what they are already
doing on kprobes.

After this patch, users are allowed to use PERF_EVENT_IOC_SET_BPF on a
uprobe perf event. Which make it possible to profile user space programs
and kernel events together using BPF.

Because of this patch, CONFIG_BPF_EVENTS should be selected by
CONFIG_UPROBE_EVENT to ensure trace_call_bpf() is compiled even if
KPROBE_EVENT is not set.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1435716878-189507-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 6 insertions, 1 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 3b9a48ae153a..1153c43428f3 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -434,7 +434,7 @@ config UPROBE_EVENT
 
 config BPF_EVENTS
         depends on BPF_SYSCALL
-        depends on KPROBE_EVENT
+        depends on KPROBE_EVENT || UPROBE_EVENT
         bool
         default y
         help
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index aa1ea7b36fa8..f97479f1ce35 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1095,11 +1095,15 @@ static void __uprobe_perf_func(struct trace_uprobe *tu,
 {
         struct trace_event_call *call = &tu->tp.call;
         struct uprobe_trace_entry_head *entry;
+        struct bpf_prog *prog = call->prog;
         struct hlist_head *head;
         void *data;
         int size, esize;
         int rctx;
 
+        if (prog && !trace_call_bpf(prog, regs))
+                return;
+
         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
 
         size = esize + tu->tp.size + dsize;
@@ -1289,6 +1293,7 @@ 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);