This patch enables multiple bpf attachments for a
kprobe/uprobe/tracepoint single trace event.
Each trace_event keeps a list of attached perf events.
When an event happens, all attached bpf programs will
be executed based on the order of attachment.

A global bpf_event_mutex lock is introduced to protect
prog_array attaching and detaching. An alternative will
be introduce a mutex lock in every trace_event_call
structure, but it takes a lot of extra memory.
So a global bpf_event_mutex lock is a good compromise.

The bpf prog detachment involves allocation of memory.
If the allocation fails, a dummy do-nothing program
will replace to-be-detached program in-place.
Signed-off-by: NYonghong Song <yhs@fb.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

__get_str(str)'s definition includes a (char *) operator
overloading that is not protected with outer ().

This patch adds () around __get_str()'s definition, enabling
some code cleanup.

Link: http://lkml.kernel.org/r/20ac1a10c2ec4ccd23e4a8ef34101fb6e4157d37.1467407618.git.bristot@redhat.com

Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Reviewed-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NDaniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

move trace_call_bpf() into helper function to minimize the size
of perf_trace_*() tracepoint handlers.
    text	   data	    bss	    dec	 	   hex	filename
10541679	5526646	2945024	19013349	1221ee5	vmlinux_before
10509422	5526646	2945024	18981092	121a0e4	vmlinux_after

It may seem that perf_fetch_caller_regs() can also be moved,
but that is incorrect, since ip/sp will be wrong.

bpf+tracepoint performance is not affected, since
perf_swevent_put_recursion_context() is now inlined.
export_symbol_gpl can also be dropped.

No measurable change in normal perf tracepoints.
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

introduce BPF_PROG_TYPE_TRACEPOINT program type and allow it to be attached
to the perf tracepoint handler, which will copy the arguments into
the per-cpu buffer and pass it to the bpf program as its first argument.
The layout of the fields can be discovered by doing
'cat /sys/kernel/debug/tracing/events/sched/sched_switch/format'
prior to the compilation of the program with exception that first 8 bytes
are reserved and not accessible to the program. This area is used to store
the pointer to 'struct pt_regs' which some of the bpf helpers will use:
+---------+
| 8 bytes | hidden 'struct pt_regs *' (inaccessible to bpf program)
+---------+
| N bytes | static tracepoint fields defined in tracepoint/format (bpf readonly)
+---------+
| dynamic | __dynamic_array bytes of tracepoint (inaccessible to bpf yet)
+---------+

Not that all of the fields are already dumped to user space via perf ring buffer
and broken application access it directly without consulting tracepoint/format.
Same rule applies here: static tracepoint fields should only be accessed
in a format defined in tracepoint/format. The order of fields and
field sizes are not an ABI.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

split allows to move expensive update of 'struct trace_entry' to later phase.
Repurpose unused 1st argument of perf_tp_event() to indicate event type.

While splitting use temp variable 'rctx' instead of '*rctx' to avoid
unnecessary loads done by the compiler due to -fno-strict-aliasing
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

now all calls to perf_trace_buf_submit() pass 0 as 4th
argument which will be repurposed in the next patch which will
change the meaning of 1st arg of perf_tp_event() to event_type
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit ee53bbd1 "tracing: Move the perf code out of trace_event.h" moved
more than just the perf code out of trace_event.h, but also removed a bit of
the tracing code too. Move it back.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The function ftrace_get_offsets_##call()
is used to find the offset into dynamically allocated trace event fields
for printing. It has nothing to do with function tracing. Rename it.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The function ftrace_define_fields_##call()
is used to define how to process the trace_event fields. It has nothing to
do with function tracing. Rename it.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The structure ftrace_event_type_funcs_##call
is used to define how the trace_events will be printed. It has nothing to
do with function tracing. Rename it.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The structure ftrace_data_offset_##call is
used to find the offsets of dynamically allocated fields in trace_events.
It has nothing to do with function tracing. Rename it.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The ftrace_raw_##call structures are built
by macros for trace events. They have nothing to do with function tracing.
Rename them.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The ftrace_trigger_soft_disabled() tests if a
trace_event is soft disabled (called but not traced), and returns true if
it is. It has nothing to do with function tracing and should be renamed.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The FTRACE_EVENT_FL_* flags are flags to
do with the trace_event files in the tracefs directory. They are not related
to function tracing. Rename them to a more descriptive name.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The ftrace_output_*() and ftrace_raw_output_*()
functions represent the trace_event code. Rename them to just trace_output
or trace_raw_output.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The ftrace_event_buffer functions and data
structures are for trace_events and not for function hooks. Rename them
to trace_event_buffer*.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The structures ftrace_event_call and
ftrace_event_class have nothing to do with the function hooks, and are
really trace_event structures. Rename ftrace_event_* to trace_event_*.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The structure ftrace_event_file is really
about trace events and not "ftrace". Rename it to trace_event_file.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The functions (un)register_ftrace_event() is
really about trace_events, and the name should be register_trace_event()
instead.

Also renamed ftrace_event_reg() to trace_event_reg() for the same reason.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The trace_event.h file is for the generic trace event code. Move
the perf related code into its own trace header file perf.h
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>