perf ebpf: Add the libbpf glue

The 'bpf-loader.[ch]' files are introduced in this patch. Which will be
the interface between perf and libbpf. bpf__prepare_load() resides in
bpf-loader.c. Following patches will enrich these two files.

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/1444826502-49291-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
new file mode 100644 (file)
index 0000000..ab56073
--- /dev/null
+++ b/tools/perf/util/bpf-loader.c
@@ -0,0 +1,57 @@
+/*
+ * bpf-loader.c
+ *
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ */
+
+#include <bpf/libbpf.h>
+#include <linux/err.h>
+#include "perf.h"
+#include "debug.h"
+#include "bpf-loader.h"
+
+#define DEFINE_PRINT_FN(name, level) \
+static int libbpf_##name(const char *fmt, ...) \
+{                                              \
+       va_list args;                           \
+       int ret;                                \
+                                               \
+       va_start(args, fmt);                    \
+       ret = veprintf(level, verbose, pr_fmt(fmt), args);\
+       va_end(args);                           \
+       return ret;                             \
+}
+
+DEFINE_PRINT_FN(warning, 0)
+DEFINE_PRINT_FN(info, 0)
+DEFINE_PRINT_FN(debug, 1)
+
+struct bpf_object *bpf__prepare_load(const char *filename)
+{
+       struct bpf_object *obj;
+       static bool libbpf_initialized;
+
+       if (!libbpf_initialized) {
+               libbpf_set_print(libbpf_warning,
+                                libbpf_info,
+                                libbpf_debug);
+               libbpf_initialized = true;
+       }
+
+       obj = bpf_object__open(filename);
+       if (!obj) {
+               pr_debug("bpf: failed to load %s\n", filename);
+               return ERR_PTR(-EINVAL);
+       }
+
+       return obj;
+}
+
+void bpf__clear(void)
+{
+       struct bpf_object *obj, *tmp;
+
+       bpf_object__for_each_safe(obj, tmp)
+               bpf_object__close(obj);
+}

diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
new file mode 100644 (file)
index 0000000..f402d7c
--- /dev/null
+++ b/tools/perf/util/bpf-loader.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015, Huawei Inc.
+ */
+#ifndef __BPF_LOADER_H
+#define __BPF_LOADER_H
+
+#include <linux/compiler.h>
+#include <linux/err.h>
+#include <string.h>
+#include "debug.h"
+
+struct bpf_object;
+
+#ifdef HAVE_LIBBPF_SUPPORT
+struct bpf_object *bpf__prepare_load(const char *filename);
+
+void bpf__clear(void);
+#else
+static inline struct bpf_object *
+bpf__prepare_load(const char *filename __maybe_unused)
+{
+       pr_debug("ERROR: eBPF object loading is disabled during compiling.\n");
+       return ERR_PTR(-ENOTSUP);
+}
+
+static inline void bpf__clear(void) { }
+#endif
+#endif