linux/tools/lib/bpf, branch v4.3

bpf tools: New API to get name from a BPF object

2015-08-31T19:53:15Z

Before this patch there's no way to connect a loaded bpf object to its source file. However, during applying perf's '--filter' to BPF object, without this connection makes things harder, because perf loads all programs together, but '--filter' setting is for each object. The API of bpf_object__open_buffer() is changed to allow passing a name. Fortunately, at this time there's only one user of it (perf test LLVM), so we change it together. Signed-off-by: Wang Nan Cc: 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/1440742821-44548-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Link all bpf objects onto a list

2015-08-07T13:16:59Z

To allow enumeration of all bpf_objects, keep them in a list (hidden to caller). bpf_object__for_each_safe() is introduced to do this iteration. It is safe even user close the object during iteration. 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/1435716878-189507-23-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Introduce accessors for struct bpf_program

2015-08-07T13:16:59Z

This patch introduces accessors for user of libbpf to retrieve section name and fd of a opened/loaded eBPF program. 'struct bpf_prog_handler' is used for that purpose. Accessors of programs section name and file descriptor are provided. Set/get private data are also impelmented. 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 Link: http://lkml.kernel.org/r/1435716878-189507-21-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Load eBPF programs in object files into kernel

2015-08-07T13:16:59Z

This patch utilizes previous introduced bpf_load_program to load programs in the ELF file into kernel. Result is stored in 'fd' field in 'struct bpf_program'. During loading, it allocs a log buffer and free it before return. Note that that buffer is not passed to bpf_load_program() if the first loading try is successful. Doesn't use a statically allocated log buffer to avoid potention multi-thread problem. Instructions collected during opening is cleared after loading. load_program() is created for loading a 'struct bpf_insn' array into kernel, bpf_program__load() calls it. By this design we have a function loads instructions into kernel. It will be used by further patches, which creates different instances from a program and load them into kernel. 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/1435716878-189507-20-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Introduce bpf_load_program() to bpf.c

2015-08-07T13:16:58Z

bpf_load_program() can be used to load bpf program into kernel. To make loading faster, first try to load without logbuf. Try again with logbuf if the first try failed. 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/1435716878-189507-19-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Relocate eBPF programs

2015-08-07T13:16:58Z

If an eBPF program accesses a map, LLVM generates a load instruction which loads an absolute address into a register, like this: ld_64 r1, ... call 2 That ld_64 instruction will be recorded in relocation section. To enable the usage of that map, relocation must be done by replacing the immediate value by real map file descriptor so it can be found by eBPF map functions. This patch to the relocation work based on information collected by patches: 'bpf tools: Collect symbol table from SHT_SYMTAB section', 'bpf tools: Collect relocation sections from SHT_REL sections' and 'bpf tools: Record map accessing instructions for each program'. For each instruction which needs relocation, it inject corresponding file descriptor to imm field. As a part of protocol, src_reg is set to BPF_PSEUDO_MAP_FD to notify kernel this is a map loading instruction. This is the final part of map relocation patch. 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/1435716878-189507-18-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Create eBPF maps defined in an object file

2015-08-07T13:16:58Z

This patch creates maps based on 'map' section in object file using bpf_create_map(), and stores the fds into an array in 'struct bpf_object'. Previous patches parse ELF object file and collects required data, but doesn't play with the kernel. They belong to the 'opening' phase. This patch is the first patch in 'loading' phase. The 'loaded' field is introduced in 'struct bpf_object' to avoid loading an object twice, because the loading phase clears resources collected during the opening which becomes useless after loading. In this patch, maps_buf is cleared. 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/1435716878-189507-17-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Add bpf.c/h for common bpf operations

2015-08-07T13:16:58Z

This patch introduces bpf.c and bpf.h, which hold common functions issuing bpf syscall. The goal of these two files is to hide syscall completely from user. Note that bpf.c and bpf.h deal with kernel interface only. Things like structure of 'map' section in the ELF object is not cared by of bpf.[ch]. We first introduce bpf_create_map(). Note that, since functions in bpf.[ch] are wrapper of sys_bpf, they don't use OO style naming. 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/1435716878-189507-16-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Record map accessing instructions for each program

2015-08-07T13:16:58Z

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

bpf tools: Collect relocation sections from SHT_REL sections

2015-08-07T13:16:57Z

This patch collects relocation sections into 'struct object'. Such sections are used for connecting maps to bpf programs. 'reloc' field in 'struct bpf_object' is introduced for storing such information. This patch simply store the data into 'reloc' field. Following patch will parse them to know the exact instructions which are needed to be relocated. Note that the collected data will be invalid after ELF object file is closed. This is the second patch related to map relocation. The first one is 'bpf tools: Collect symbol table from SHT_SYMTAB section'. The principle of map relocation is described in its commit message. 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/1435716878-189507-14-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo