From 340909152ae5a588b9a77a85df35d61ec3523833 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Wed, 1 Jul 2015 02:14:02 +0000 Subject: bpf tools: Record map accessing instructions for each program This patch records the indices of instructions which are needed to be relocated. That information is saved in the 'reloc_desc' field in 'struct bpf_program'. In the loading phase (this patch takes effect in the opening phase), the collected instructions will be replaced by map loading instructions. Since we are going to close the ELF file and clear all data at the end of the 'opening' phase, the ELF information will no longer be valid in the 'loading' phase. We have to locate the instructions before maps are loaded, instead of directly modifying the instruction. 'struct bpf_map_def' is introduced in this patch to let us know how many maps are defined in the object. This is the third part of map relocation. The principle of map relocation is described in commit message of 'bpf tools: Collect symbol table from SHT_SYMTAB section'. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-15-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/bpf/libbpf.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'tools/lib/bpf/libbpf.h') diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index dc966dd9fd75..6e75acdb9112 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -30,4 +30,17 @@ struct bpf_object *bpf_object__open_buffer(void *obj_buf, size_t obj_buf_sz); void bpf_object__close(struct bpf_object *object); +/* + * We don't need __attribute__((packed)) now since it is + * unnecessary for 'bpf_map_def' because they are all aligned. + * In addition, using it will trigger -Wpacked warning message, + * and will be treated as an error due to -Werror. + */ +struct bpf_map_def { + unsigned int type; + unsigned int key_size; + unsigned int value_size; + unsigned int max_entries; +}; + #endif -- cgit v1.2.3