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authorArnaldo Carvalho de Melo <acme@redhat.com>2018-08-06 09:02:26 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-08-08 15:55:54 -0300
commit7402e543a74a08ae630234012356ff5cf947bd61 (patch)
tree58d1fe30b8b32ae1ef569a5759a235bb0b68d723 /tools
parente6902d1b7326149952abf8e7f07513e254668e52 (diff)
downloadlinux-7402e543a74a08ae630234012356ff5cf947bd61.tar.bz2
perf bpf: Add struct bpf_map struct
A helper structure used by eBPF C program to describe map attributes to elf_bpf loader, to be used initially by the special __bpf_stdout__ map used to print strings into the perf ring buffer in BPF scripts, e.g.: Using the upcoming stdio.h and puts() macros to use the __bpf_stdout__ map to add strings to the ring buffer: # cat tools/perf/examples/bpf/hello.c #include <stdio.h> int syscall_enter(openat)(void *args) { puts("Hello, world\n"); return 0; } license(GPL); # # cat ~/.perfconfig [llvm] dump-obj = true # perf trace -e openat,tools/perf/examples/bpf/hello.c/call-graph=dwarf/ cat /etc/passwd > /dev/null LLVM: dumping tools/perf/examples/bpf/hello.o 0.016 ( ): __bpf_stdout__:Hello, world 0.018 ( 0.010 ms): cat/9079 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC ) = 3 0.057 ( ): __bpf_stdout__:Hello, world 0.059 ( 0.011 ms): cat/9079 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC ) = 3 0.417 ( ): __bpf_stdout__:Hello, world 0.419 ( 0.009 ms): cat/9079 openat(dfd: CWD, filename: /etc/passwd ) = 3 # # file tools/perf/examples/bpf/hello.o tools/perf/examples/bpf/hello.o: ELF 64-bit LSB relocatable, *unknown arch 0xf7* version 1 (SYSV), not stripped # readelf -SW tools/perf/examples/bpf/hello.o There are 10 section headers, starting at offset 0x208: Section Headers: [Nr] Name Type Address Off Size ES Flg Lk Inf Al [ 0] NULL 0000000000000000 000000 000000 00 0 0 0 [ 1] .strtab STRTAB 0000000000000000 000188 00007f 00 0 0 1 [ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4 [ 3] syscalls:sys_enter_openat PROGBITS 0000000000000000 000040 000088 00 AX 0 0 8 [ 4] .relsyscalls:sys_enter_openat REL 0000000000000000 000178 000010 10 9 3 8 [ 5] maps PROGBITS 0000000000000000 0000c8 00001c 00 WA 0 0 4 [ 6] .rodata.str1.1 PROGBITS 0000000000000000 0000e4 00000e 01 AMS 0 0 1 [ 7] license PROGBITS 0000000000000000 0000f2 000004 00 WA 0 0 1 [ 8] version PROGBITS 0000000000000000 0000f8 000004 00 WA 0 0 4 [ 9] .symtab SYMTAB 0000000000000000 000100 000078 18 1 1 8 Key to Flags: W (write), A (alloc), X (execute), M (merge), S (strings), I (info), L (link order), O (extra OS processing required), G (group), T (TLS), C (compressed), x (unknown), o (OS specific), E (exclude), p (processor specific) # readelf -s tools/perf/examples/bpf/hello.o Symbol table '.symtab' contains 5 entries: Num: Value Size Type Bind Vis Ndx Name 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND 1: 0000000000000000 0 NOTYPE GLOBAL DEFAULT 5 __bpf_stdout__ 2: 0000000000000000 0 NOTYPE GLOBAL DEFAULT 7 _license 3: 0000000000000000 0 NOTYPE GLOBAL DEFAULT 8 _version 4: 0000000000000000 0 NOTYPE GLOBAL DEFAULT 3 syscall_enter_openat # Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-81fg60om2ifnatsybzwmiga3@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/include/bpf/bpf.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/tools/perf/include/bpf/bpf.h b/tools/perf/include/bpf/bpf.h
index 2873cdde293f..1f632b56bb34 100644
--- a/tools/perf/include/bpf/bpf.h
+++ b/tools/perf/include/bpf/bpf.h
@@ -4,6 +4,20 @@
#include <uapi/linux/bpf.h>
+/*
+ * A helper structure used by eBPF C program to describe map attributes to
+ * elf_bpf loader, taken from tools/testing/selftests/bpf/bpf_helpers.h:
+ */
+struct bpf_map {
+ unsigned int type;
+ unsigned int key_size;
+ unsigned int value_size;
+ unsigned int max_entries;
+ unsigned int map_flags;
+ unsigned int inner_map_idx;
+ unsigned int numa_node;
+};
+
#define SEC(NAME) __attribute__((section(NAME), used))
#define probe(function, vars) \