linux/tools/lib/bpf, branch v4.7

perf bpf: Check relocation target section

2016-01-26T15:11:01Z

Libbpf should check the target section before doing relocation to ensure the relocation is correct. If not, a bug in LLVM causes an error. See [1]. Also, if an incorrect BPF script uses both global variable and map, global variable whould be treated as map and be relocated without error. This patch saves the id of the map section into obj->efile and compare target section of a relocation symbol against it during relocation. Previous patch introduces a test case about this problem. After this patch: # ~/perf test BPF 37: Test BPF filter : 37.1: Test basic BPF filtering : Ok 37.2: Test BPF prologue generation : Ok 37.3: Test BPF relocation checker : Ok # perf test -v BPF ... 37.3: Test BPF relocation checker : ... libbpf: loading object '[bpf_relocation_test]' from buffer libbpf: section .strtab, size 126, link 0, flags 0, type=3 libbpf: section .text, size 0, link 0, flags 6, type=1 libbpf: section .data, size 0, link 0, flags 3, type=1 libbpf: section .bss, size 0, link 0, flags 3, type=8 libbpf: section func=sys_write, size 104, link 0, flags 6, type=1 libbpf: found program func=sys_write libbpf: section .relfunc=sys_write, size 16, link 10, flags 0, type=9 libbpf: section maps, size 16, link 0, flags 3, type=1 libbpf: maps in [bpf_relocation_test]: 16 bytes libbpf: section license, size 4, link 0, flags 3, type=1 libbpf: license of [bpf_relocation_test] is GPL libbpf: section version, size 4, link 0, flags 3, type=1 libbpf: kernel version of [bpf_relocation_test] is 40400 libbpf: section .symtab, size 144, link 1, flags 0, type=2 libbpf: map 0 is "my_table" libbpf: collecting relocating info for: 'func=sys_write' libbpf: Program 'func=sys_write' contains non-map related relo data pointing to section 65522 bpf: failed to load buffer Compile BPF program failed. test child finished with 0 ---- end ---- Test BPF filter subtest 2: Ok [1] https://llvm.org/bugs/show_bug.cgi?id=26243 Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Tested-by: Arnaldo Carvalho de Melo Cc: "David S. Miller" Cc: Brendan Gregg Cc: Daniel Borkmann Cc: He Kuang Cc: Jiri Olsa Cc: Li Zefan Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Will Deacon Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1453715801-7732-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Fix build breakage due to libbpf

2016-01-11T22:22:21Z

perf build is currently (v4.4-rc5) broken on powerpc: bpf.c:28:4: error: #error __NR_bpf not defined. libbpf does not support your arch. # error __NR_bpf not defined. libbpf does not support your arch. ^ Fix this by including tools/scripts/Makefile.arch for the proper $ARCH macro. While at it, remove redundant LP64 macro definition. Also, since libbpf require $(srctree) now, detect the path of srctree like perf. Signed-off-by: Naveen N. Rao Acked-by: Jiri Olsa Cc: Sukadev Bhattiprolu Cc: Wang Nan Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1452520124-2073-10-git-send-email-wangnan0@huawei.com [Use tools/scripts/Makefile.arch] Signed-off-by: Wang Nan Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix PowerPC native building

2016-01-11T22:22:20Z

Checks BPF syscall number, turn off libbpf building on platform doesn't correctly support sys_bpf instead of blocking compiling. Reported-and-Tested-by: Naveen N. Rao Signed-off-by: Wang Nan Acked-by: Jiri Olsa Cc: Sukadev Bhattiprolu Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1452520124-2073-7-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

tools bpf: Add *.cmd files clean up

2016-01-11T15:08:30Z

Add *.cmd files to be removed within clean target. Reported-and-Tested-by: Arnaldo Carvalho de Melo Signed-off-by: Jiri Olsa Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1452509693-13452-3-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf build: Use FEATURE-DUMP in bpf subproject

2016-01-06T23:11:14Z

Using FEATURE-DUMP in bpf subproject for features detection in case bpf is built via perf. Keeping the current features detection otherwise. Signed-off-by: Jiri Olsa Tested-by: Wang Nan Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama Link: http://lkml.kernel.org/r/1450893514-9158-6-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

tools lib bpf: Fetch map names from correct strtab

2015-12-11T11:53:04Z

Namhyung Kim pointed out a potential problem in original code that it fetches names of maps from section header string table, which is used to store section names. Original code doesn't cause error because of a LLVM behavior that, it combines shstrtab into strtab. For example: $ echo 'int func() {return 0;}' | x86_64-oe-linux-clang -x c -o temp.o -c - $ readelf -h ./temp.o ELF Header: Magic: 7f 45 4c 46 02 01 01 03 00 00 00 00 00 00 00 00 ... Section header string table index: 1 $ readelf -S ./temp.o There are 10 section headers, starting at offset 0x288: Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align [ 0] NULL 0000000000000000 00000000 0000000000000000 0000000000000000 0 0 0 [ 1] .strtab STRTAB 0000000000000000 00000230 0000000000000051 0000000000000000 0 0 1 ... $ readelf -p .strtab ./temp.o String dump of section '.strtab': [ 1] .text [ 7] .comment [ 10] .bss [ 15] .note.GNU-stack [ 25] .rela.eh_frame [ 34] func [ 39] .strtab [ 41] .symtab [ 49] .data [ 4f] - $ readelf -p .shstrtab ./temp.o readelf: Warning: Section '.shstrtab' was not dumped because it does not exist! Where, 'section header string table index' points to '.strtab', and symbol names are also stored there. However, in case of gcc: $ echo 'int func() {return 0;}' | gcc -x c -o temp.o -c - $ readelf -p .shstrtab ./temp.o String dump of section '.shstrtab': [ 1] .symtab [ 9] .strtab [ 11] .shstrtab [ 1b] .text [ 21] .data [ 27] .bss [ 2c] .comment [ 35] .note.GNU-stack [ 45] .rela.eh_frame $ readelf -p .strtab ./temp.o String dump of section '.strtab': [ 1] func They are separated sections. Although original code doesn't cause error, we'd better use canonical method for fetching symbol names to avoid potential behavior changing. This patch learns from readelf's code, fetches string from sh_link of .symbol section. Signed-off-by: Wang Nan Reported-and-Acked-by: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1449541544-67621-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

tools lib bpf: Check return value of strdup when reading map names

2015-12-11T11:51:09Z

Commit 561bbccac72d08babafaa33fd7fa9100ec4c9fb6 ("tools lib bpf: Extract and collect map names from BPF object file") forgets checking return value of strdup(). This patch fixes it. It also checks names pointer before strcmp() for safety. Signed-off-by: Wang Nan Acked-by: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Fixes: 561bbccac72d ("tools lib bpf: Extract and collect map names from BPF object file") Link: http://lkml.kernel.org/r/1449541544-67621-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

tools lib bpf: Extract and collect map names from BPF object file

2015-11-28T00:59:53Z

This patch collects name of maps in BPF object files and saves them into 'maps' field in 'struct bpf_object'. 'bpf_object__get_map_by_name' is introduced to retrive fd and definitions of a map through its name. Signed-off-by: He Kuang Cc: Alexei Starovoitov Cc: He Kuang Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1448614067-197576-3-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan Signed-off-by: Arnaldo Carvalho de Melo

tools lib bpf: Collect map definition in bpf_object

2015-11-28T00:57:09Z

This patch collects more information from maps sections in BPF object files into 'struct bpf_object', enables later patches access those information (such as the type and size of the map). In this patch, a new handler 'struct bpf_map' is extracted in parallel with bpf_object and bpf_program. Its iterator and accessor is also created. Signed-off-by: Wang Nan Cc: Alexei Starovoitov Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1448614067-197576-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Add helper function for updating bpf maps elements

2015-11-26T20:21:24Z

Add bpf_map_update_elem() helper function which calls the sys_bpf syscall to update elements in bpf maps. Upcoming patches will use it to adjust data in map through the perf command line. Signed-off-by: He Kuang Cc: Alexei Starovoitov Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Wang Nan Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1448372181-151723-4-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan Signed-off-by: Arnaldo Carvalho de Melo