[PATCH 28/34] perf clang jit: Access BPF map

From: Wang Nan
Date: Mon Nov 14 2016 - 23:09:18 EST


---
tools/perf/util/bpf-loader.c | 37 +++++++++++++++++++++++++++++++++++++
tools/perf/util/bpf-loader.h | 19 +++++++++++++++++++
2 files changed, 56 insertions(+)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 81c6fed..86aa99b 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -19,6 +19,7 @@
#include "parse-events.h"
#include "llvm-utils.h"
#include "c++/clang-c.h"
+#include "asm/bug.h" // for WARN_ONCE

#define DEFINE_PRINT_FN(name, level) \
static int libbpf_##name(const char *fmt, ...) \
@@ -1644,6 +1645,28 @@ int bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
return 0;
}

+int bpf__map_fd(struct bpf_object *obj, void *jit_map)
+{
+ struct bpf_obj_priv *priv = bpf_object__priv(obj);
+ struct bpf_map *map;
+ size_t map_offset;
+ void *map_base;
+
+ if (IS_ERR(priv))
+ return PTR_ERR(priv);
+ if (!priv)
+ return -EINVAL;
+
+ map_base = priv->map_base;
+ map_offset = jit_map - map_base;
+ map = bpf_object__find_map_by_offset(obj, map_offset);
+ WARN_ONCE(IS_ERR(map), "can't find map offset %zu from '%s'\n",
+ map_offset, bpf_object__name(obj));
+ if (IS_ERR(map))
+ return -ENOENT;
+ return bpf_map__fd(map);
+}
+
#define ERRNO_OFFSET(e) ((e) - __BPF_LOADER_ERRNO__START)
#define ERRCODE_OFFSET(c) ERRNO_OFFSET(BPF_LOADER_ERRNO__##c)
#define NR_ERRNO (__BPF_LOADER_ERRNO__END - __BPF_LOADER_ERRNO__START)
@@ -1825,3 +1848,17 @@ int bpf__strerror_setup_stdout(struct perf_evlist *evlist __maybe_unused,
bpf__strerror_end(buf, size);
return 0;
}
+
+int bpf__strerror_map_fd(struct bpf_object *obj, void *jit_map,
+ int err, char *buf, size_t size)
+{
+ struct bpf_obj_priv *priv = bpf_object__priv(obj);
+ ptrdiff_t offset = priv ? jit_map - priv->map_base : jit_map - NULL;
+
+ bpf__strerror_head(err, buf, size);
+ bpf__strerror_entry(EINVAL, "No map in BPF object %s", bpf_object__name(obj));
+ bpf__strerror_entry(ENOENT, "Can't find map offset %lx in BPF object %s",
+ (unsigned long)offset, bpf_object__name(obj));
+ bpf__strerror_end(buf, size);
+ return 0;
+}
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index f2b737b..c40812b 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -84,6 +84,9 @@ int bpf__setup_stdout(struct perf_evlist *evlist);
int bpf__strerror_setup_stdout(struct perf_evlist *evlist, int err,
char *buf, size_t size);

+int bpf__map_fd(struct bpf_object *obj, void *jit_map);
+int bpf__strerror_map_fd(struct bpf_object *obj, void *jit_map,
+ int err, char *buf, size_t size);
#else
static inline struct bpf_object *
bpf__prepare_load(const char *filename __maybe_unused,
@@ -136,6 +139,13 @@ bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
}

static inline int
+bpf__map_fd(struct bpf_object *obj __maybe_unused,
+ void *map_ptr __maybe_unused)
+{
+ return -ENOTSUP;
+}
+
+static inline int
__bpf_strerror(char *buf, size_t size)
{
if (!size)
@@ -196,5 +206,14 @@ bpf__strerror_setup_stdout(struct perf_evlist *evlist __maybe_unused,
{
return __bpf_strerror(buf, size);
}
+
+static inline int
+bpf__strerror_map_fd(struct bpf_object *obj __maybe_unused,
+ void *jit_map __maybe_unused,
+ int err __maybe_unused,
+ char *buf, size_t size);
+{
+ return __bpf_strerror(buf, size);
+}
#endif
#endif
--
2.10.1