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

[Wang Nan]

---
 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