Commit 04a22fae authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarWang Nan <wangnan0@huawei.com>
Acked-by: default avatarAlexei 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 098d2164

include/linux/trace_events.h

+5 −0
Original line number Diff line number Diff line
@@ -243,6 +243,7 @@ enum { 
	TRACE_EVENT_FL_USE_CALL_FILTER_BIT,

	TRACE_EVENT_FL_TRACEPOINT_BIT,

	TRACE_EVENT_FL_KPROBE_BIT,

	TRACE_EVENT_FL_UPROBE_BIT,

};



/*
@@ -257,6 +258,7 @@ enum { 
 *  USE_CALL_FILTER - For trace internal events, don't use file filter

 *  TRACEPOINT    - Event is a tracepoint

 *  KPROBE        - Event is a kprobe

 *  UPROBE        - Event is a uprobe

 */

enum {

	TRACE_EVENT_FL_FILTERED		= (1 << TRACE_EVENT_FL_FILTERED_BIT),
@@ -267,8 +269,11 @@ enum { 
	TRACE_EVENT_FL_USE_CALL_FILTER	= (1 << TRACE_EVENT_FL_USE_CALL_FILTER_BIT),

	TRACE_EVENT_FL_TRACEPOINT	= (1 << TRACE_EVENT_FL_TRACEPOINT_BIT),

	TRACE_EVENT_FL_KPROBE		= (1 << TRACE_EVENT_FL_KPROBE_BIT),

	TRACE_EVENT_FL_UPROBE		= (1 << TRACE_EVENT_FL_UPROBE_BIT),

};



#define TRACE_EVENT_FL_UKPROBE (TRACE_EVENT_FL_KPROBE | TRACE_EVENT_FL_UPROBE)



struct trace_event_call {

	struct list_head	list;

	struct trace_event_class *class;

kernel/events/core.c

+2 −2
Original line number Diff line number Diff line
@@ -6846,8 +6846,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 
	if (event->tp_event->prog)

		return -EEXIST;



	if (!(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))

		/* bpf programs can only be attached to kprobes */

	if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))

		/* bpf programs can only be attached to u/kprobes */

		return -EINVAL;



	prog = bpf_prog_get(prog_fd);

kernel/trace/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

kernel/trace/trace_uprobe.c

+5 −0
Original line number Diff line number Diff line
@@ -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);

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