[PATCH 02/27] perf ebpf: Add the libbpf glue

From: Wang Nan
Date: Mon Aug 10 2015 - 02:22:36 EST


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. Dummy functions should be used because bpf-loader.c is
available only when CONFIG_LIBBPF is on.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kaixu Xia <xiakaixu@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/n/1436445342-1402-19-git-send-email-wangnan0@xxxxxxxxxx
[ split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/bpf-loader.c | 89 ++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/bpf-loader.h | 44 ++++++++++++++++++++++
2 files changed, 133 insertions(+)
create mode 100644 tools/perf/util/bpf-loader.c
create mode 100644 tools/perf/util/bpf-loader.h

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
new file mode 100644
index 0000000..baabb95
--- /dev/null
+++ b/tools/perf/util/bpf-loader.c
@@ -0,0 +1,89 @@
+/*
+ * bpf-loader.c
+ *
+ * Copyright (C) 2015 Wang Nan <wangnan0@xxxxxxxxxx>
+ * Copyright (C) 2015 Huawei Inc.
+ */
+
+#include <bpf/libbpf.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)
+
+static bool libbpf_initialized;
+
+int bpf__prepare_load(const char *filename)
+{
+ struct bpf_object *obj;
+
+ if (!libbpf_initialized)
+ libbpf_set_print(libbpf_warning,
+ libbpf_info,
+ libbpf_debug);
+
+ obj = bpf_object__open(filename);
+ if (!obj) {
+ pr_debug("bpf: failed to load %s\n", filename);
+ return -EINVAL;
+ }
+
+ /*
+ * Throw object pointer away: it will be retrived using
+ * bpf_objects iterater.
+ */
+
+ return 0;
+}
+
+void bpf__clear(void)
+{
+ struct bpf_object *obj, *tmp;
+
+ bpf_object__for_each_safe(obj, tmp)
+ bpf_object__close(obj);
+}
+
+#define bpf__strerror_head(err, buf, size) \
+ char sbuf[STRERR_BUFSIZE], *emsg;\
+ if (err < 0)\
+ err = -err;\
+ emsg = strerror_r(err, sbuf, sizeof(sbuf));\
+ switch (err) {\
+ default:\
+ scnprintf(buf, size, "%s", emsg);\
+ break;
+
+#define bpf__strerror_entry(val, fmt...)\
+ case val: {\
+ scnprintf(buf, size, fmt);\
+ break;\
+ }
+
+#define bpf__strerror_end()\
+ }\
+
+int bpf__strerror_prepare_load(const char *filename, int err,
+ char *buf, size_t size)
+{
+ bpf__strerror_head(err, buf, size);
+ bpf__strerror_entry(EINVAL, "%s: BPF object file '%s' is invalid",
+ emsg, filename)
+ bpf__strerror_end();
+ return 0;
+}
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
new file mode 100644
index 0000000..d78d5dd
--- /dev/null
+++ b/tools/perf/util/bpf-loader.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2015, Wang Nan <wangnan0@xxxxxxxxxx>
+ * Copyright (C) 2015, Huawei Inc.
+ */
+#ifndef __BPF_LOADER_H
+#define __BPF_LOADER_H
+
+#include <linux/compiler.h>
+#include <string.h>
+#include "debug.h"
+
+#ifdef HAVE_LIBBPF_SUPPORT
+int bpf__prepare_load(const char *filename);
+int bpf__strerror_prepare_load(const char *filename, int err,
+ char *buf, size_t size);
+
+void bpf__clear(void);
+#else
+static inline int bpf__prepare_load(const char *filename __maybe_unused)
+{
+ pr_debug("ERROR: eBPF object loading is disabled during compiling.\n");
+ return -1;
+}
+
+static inline void bpf__clear(void) { }
+
+static inline int
+__bpf_strerror(char *buf, size_t size)
+{
+ strncpy(buf,
+ "ERROR: eBPF object loading is disabled during compiling.\n",
+ size);
+ return 0;
+}
+
+static inline int
+bpf__strerror_prepare_load(const char *filename __maybe_unused,
+ int err __maybe_unused,
+ char *buf, size_t size)
+{
+ return __bpf_strerror(buf, size);
+}
+#endif
+#endif
--
1.8.3.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/