By introducing new rules in tools/perf/util/parse-events.[ly], this
patch enables 'perf record --event bpf_file.o' to select events by an
eBPF object file. It calls parse_events_load_bpf() to load that file,
which uses bpf__prepare_load() and finally calls bpf_object__open() for
the object files.

Instead of introducing evsel to evlist during parsing, events selected
by eBPF object files are appended separately. The reason is:

 1. During parsing, the probing points have not been initialized.

 2. Currently we are unable to call add_perf_probe_events() twice,
    therefore we have to wait until all such events are collected,
    then probe all points by one call.

The real probing and selecting is reside in following patches.

Commiter note:

Testing if the event parsing changes indeed call the BPF loading
routines:

  [root@felicio ~]# ls -la foo.o
  ls: cannot access foo.o: No such file or directory
  [root@felicio ~]# perf record --event foo.o sleep
  libbpf: failed to open foo.o: No such file or directory
  bpf: failed to load foo.o
  invalid or unsupported event: 'foo.o'
  Run 'perf list' for a list of valid events

   usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available 
events
  [root@felicio ~]#

Yes, it does this time around.

Signed-off-by: Wang Nan <wangn...@huawei.com>
Acked-by: Alexei Starovoitov <a...@plumgrid.com>
Tested-by: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Brendan Gregg <brendan.d.gr...@gmail.com>
Cc: Daniel Borkmann <dan...@iogearbox.net>
Cc: David Ahern <dsah...@gmail.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Kaixu Xia <xiaka...@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
Link: 
http://lkml.kernel.org/n/1436445342-1402-19-git-send-email-wangn...@huawei.com
[ The veprintf() and bpf loader parts were split from this one ]
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
 tools/perf/util/Build          |  1 +
 tools/perf/util/parse-events.c | 26 ++++++++++++++++++++++++++
 tools/perf/util/parse-events.h |  3 +++
 tools/perf/util/parse-events.l |  3 +++
 tools/perf/util/parse-events.y | 18 +++++++++++++++++-
 5 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 1ce0adc..309b2d2 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -80,6 +80,7 @@ libperf-y += thread-stack.o
 libperf-$(CONFIG_AUXTRACE) += auxtrace.o
 libperf-y += parse-branch-options.o
 
+libperf-$(CONFIG_LIBBPF) += bpf-loader.o
 libperf-$(CONFIG_LIBELF) += symbol-elf.o
 libperf-$(CONFIG_LIBELF) += probe-file.o
 libperf-$(CONFIG_LIBELF) += probe-event.o
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 828936d..dc5a03c 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -19,6 +19,7 @@
 #include "thread_map.h"
 #include "cpumap.h"
 #include "asm/bug.h"
+#include "bpf-loader.h"
 
 #define MAX_NAME_LEN 100
 
@@ -481,6 +482,31 @@ int parse_events_add_tracepoint(struct list_head *list, 
int *idx,
                return add_tracepoint_event(list, idx, sys, event);
 }
 
+int parse_events_load_bpf(struct parse_events_evlist *data,
+                         struct list_head *list __maybe_unused,
+                         char *bpf_file_name)
+{
+       int err;
+       char errbuf[BUFSIZ];
+
+       /*
+        * Currently don't link any event to list. BPF object files
+        * should be saved to a seprated list and processed together.
+        *
+        * Things could be changed if we solve perf probe reentering
+        * problem. After that probe events file by file is possible.
+        * However, probing cost is still need to be considered.
+        */
+       err = bpf__prepare_load(bpf_file_name);
+       if (err) {
+               bpf__strerror_prepare_load(bpf_file_name, err,
+                                          errbuf, sizeof(errbuf));
+               data->error->str = strdup(errbuf);
+               data->error->help = strdup("(add -v to see detail)");
+       }
+       return err;
+}
+
 static int
 parse_breakpoint_type(const char *type, struct perf_event_attr *attr)
 {
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index e6f9aacc..51ca930 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -116,6 +116,9 @@ int parse_events__modifier_group(struct list_head *list, 
char *event_mod);
 int parse_events_name(struct list_head *list, char *name);
 int parse_events_add_tracepoint(struct list_head *list, int *idx,
                                char *sys, char *event);
+int parse_events_load_bpf(struct parse_events_evlist *data,
+                         struct list_head *list,
+                         char *bpf_file_name);
 int parse_events_add_numeric(struct parse_events_evlist *data,
                             struct list_head *list,
                             u32 type, u64 config,
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index f542750..1067caf 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -115,6 +115,7 @@ do {                                                        
\
 group          [^,{}/]*[{][^}]*[}][^,{}/]*
 event_pmu      [^,{}/]+[/][^/]*[/][^,{}/]*
 event          [^,{}/]+
+bpf_object     .*\.(o|bpf)
 
 num_dec                [0-9]+
 num_hex                0x[a-fA-F0-9]+
@@ -159,6 +160,7 @@ modifier_bp [rwx]{1,3}
                }
 
 {event_pmu}    |
+{bpf_object}   |
 {event}                {
                        BEGIN(INITIAL);
                        REWIND(1);
@@ -261,6 +263,7 @@ r{num_raw_hex}              { return raw(yyscanner); }
 {num_hex}              { return value(yyscanner, 16); }
 
 {modifier_event}       { return str(yyscanner, PE_MODIFIER_EVENT); }
+{bpf_object}           { return str(yyscanner, PE_BPF_OBJECT); }
 {name}                 { return pmu_str_check(yyscanner); }
 "/"                    { BEGIN(config); return '/'; }
 -                      { return '-'; }
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 591905a..3ee3a32 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -42,6 +42,7 @@ static inc_group_count(struct list_head *list,
 %token PE_VALUE PE_VALUE_SYM_HW PE_VALUE_SYM_SW PE_RAW PE_TERM
 %token PE_EVENT_NAME
 %token PE_NAME
+%token PE_BPF_OBJECT
 %token PE_MODIFIER_EVENT PE_MODIFIER_BP
 %token PE_NAME_CACHE_TYPE PE_NAME_CACHE_OP_RESULT
 %token PE_PREFIX_MEM PE_PREFIX_RAW PE_PREFIX_GROUP
@@ -53,6 +54,7 @@ static inc_group_count(struct list_head *list,
 %type <num> PE_RAW
 %type <num> PE_TERM
 %type <str> PE_NAME
+%type <str> PE_BPF_OBJECT
 %type <str> PE_NAME_CACHE_TYPE
 %type <str> PE_NAME_CACHE_OP_RESULT
 %type <str> PE_MODIFIER_EVENT
@@ -69,6 +71,7 @@ static inc_group_count(struct list_head *list,
 %type <head> event_legacy_tracepoint
 %type <head> event_legacy_numeric
 %type <head> event_legacy_raw
+%type <head> event_bpf_file
 %type <head> event_def
 %type <head> event_mod
 %type <head> event_name
@@ -198,7 +201,8 @@ event_def: event_pmu |
           event_legacy_mem |
           event_legacy_tracepoint sep_dc |
           event_legacy_numeric sep_dc |
-          event_legacy_raw sep_dc
+          event_legacy_raw sep_dc |
+          event_bpf_file
 
 event_pmu:
 PE_NAME '/' event_config '/'
@@ -420,6 +424,18 @@ PE_RAW
        $$ = list;
 }
 
+event_bpf_file:
+PE_BPF_OBJECT
+{
+       struct parse_events_evlist *data = _data;
+       struct list_head *list;
+
+       ALLOC_LIST(list);
+       ABORT_ON(parse_events_load_bpf(data, list, $1));
+       $$ = list;
+}
+
+
 start_terms: event_config
 {
        struct parse_events_terms *data = _data;
-- 
1.8.3.4

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