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Groups > linux.kernel > #1522326

[PATCH 07/34] tools lib bpf: Retrive bpf_map through offset of bpf_map_def

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Add a new API to libbpf, caller is able to get bpf_map through the
offset of bpf_map_def to 'maps' section.

The API will be used to help jitted perf hook code find fd of a map.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/lib/bpf/libbpf.c | 12 ++++++++++++
 tools/lib/bpf/libbpf.h |  8 ++++++++
 2 files changed, 20 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 866d5cd..2e97459 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1524,3 +1524,15 @@ bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
 	}
 	return NULL;
 }
+
+struct bpf_map *
+bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
+{
+	int i;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		if (obj->maps[i].offset == offset)
+			return &obj->maps[i];
+	}
+	return ERR_PTR(-ENOENT);
+}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 0c0b012..a5a8b86 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -24,6 +24,7 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <linux/err.h>
+#include <sys/types.h>  // for size_t
 
 enum libbpf_errno {
 	__LIBBPF_ERRNO__START = 4000,
@@ -200,6 +201,13 @@ struct bpf_map;
 struct bpf_map *
 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name);
 
+/*
+ * Get bpf_map through the offset of corresponding struct bpf_map_def
+ * in the bpf object file.
+ */
+struct bpf_map *
+bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset);
+
 struct bpf_map *
 bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
 #define bpf_map__for_each(pos, obj)		\
-- 
2.10.1

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[PATCH 00/34] perf clang: Builtin clang and perfhook support Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 21/34] perf clang: Pass CFLAGS to builtin clang Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 33/34] perf clang builtin: Define hook helpers by default Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 28/34] perf clang jit: Access BPF map Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 16/34] perf clang: Allow passing CFLAGS to builtin clang Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 23/34] perf clang jit: Insignt BPF and JIT functions in a Module Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 02/34] perf record: Fix segfault when running with suid and kptr_restrict is 1 Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 06/34] tools lib bpf: Add private field for bpf_object Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:10 +0100
  [PATCH 03/34] tools perf: Add missing struct defeinition in probe_event.h Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 01/34] perf tools: Fix kernel version error in ubuntu Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 24/34] perf clang jit: add PerfModule::doJIT to JIT perfhook functions Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 30/34] perf clang: Link BPF functions declaration into perf Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 11/34] tools build: Add feature detection for LLVM Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 32/34] perf clang: Include helpers to BPF scripts Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 05/34] tools lib bpf: Add missing bpf map functions Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
    Re: [PATCH 05/34] tools lib bpf: Add missing bpf map functions "Wangnan (F)" <wangnan0@huawei.com> - 2016-11-17 04:30 +0100
  [PATCH 31/34] perf clang: Declare BPF functions for BPF scripts automatically Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 29/34] perf clang jit: Allow jitted perf hook access BPF maps Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 34/34] perf clang git: Export getpid() to perf hook Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 09/34] perf tools: Pass context to perf hook functions Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 22/34] perf clang jit: Wrap llvm::Module using PerfModule Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 25/34] perf clang jit: Export functions for jitted code Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 20/34] perf clang: Pass full path to builtin clang Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 18/34] perf clang: Support compile IR to BPF object and add testcase Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 15/34] perf clang: Use real file system for #include Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 27/34] perf clang jit: Collect the lowest address in maps section as map_base Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 17/34] perf clang: Update test case to use real BPF script Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 13/34] perf build: Add clang and llvm compile and linking support Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 12/34] tools build: Add feature detection for clang Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 08/34] perf tools: Introduce perf hooks Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 07/34] tools lib bpf: Retrive bpf_map through offset of bpf_map_def Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 26/34] perf clang jit: Actually JIT and hook in bpf loader Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 14/34] perf clang: Add builtin clang support ant test case Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 10/34] perf llvm: Extract helpers in llvm-utils.c Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  [PATCH 19/34] perf clang: Compile BPF script use builtin clang support Wang Nan <wangnan0@huawei.com> - 2016-11-15 05:20 +0100
  Re: [PATCH 00/34] perf clang: Builtin clang and perfhook support "Wangnan (F)" <wangnan0@huawei.com> - 2016-11-15 05:40 +0100

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