![Wang Nan](/assets/img/avatar_default.png)
This patch replaces the original toy BPF program with the previously introduced bpf-script-example.c. Dynamically embeddeding it into 'llvm-src-base.c'. The newly introduced BPF program attaches a BPF program to 'sys_epoll_pwait()'. perf itself never use that syscall, so further test can verify their result with it. The program would generate 1 sample in every 2 calls of epoll_pwait() system call. Since the resulting BPF object is useful per se for further tests, test_llvm__fetch_bpf_obj() is introduced for creating BPF objects from source. The LLVM test was rewritten to use it. Committer note: Running it: [root@zoo wb]# perf test -v LLVM 35: Test LLVM searching and compiling : --- start --- test child forked, pid 17740 Kernel build dir is set to /lib/modules/4.3.0-rc1+/build set env: KBUILD_DIR=/lib/modules/4.3.0-rc1+/build unset env: KBUILD_OPTS include option is set to -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h set env: NR_CPUS=4 set env: LINUX_VERSION_CODE=0x40300 set env: CLANG_EXEC=/usr/libexec/icecc/bin/clang set env: CLANG_OPTIONS=-xc set env: KERNEL_INC_OPTIONS= -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h set env: WORKING_DIR=/lib/modules/4.3.0-rc1+/build set env: CLANG_SOURCE=- llvm compiling command template: echo '/* * bpf-script-example.c * Test basic LLVM building */ #ifndef LINUX_VERSION_CODE # error Need LINUX_VERSION_CODE # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig' #endif #define BPF_ANY 0 #define BPF_MAP_TYPE_ARRAY 2 #define BPF_FUNC_map_lookup_elem 1 #define BPF_FUNC_map_update_elem 2 static void *(*bpf_map_lookup_elem)(void *map, void *key) = (void *) BPF_FUNC_map_lookup_elem; static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) = (void *) BPF_FUNC_map_update_elem; struct bpf_map_def { unsigned int type; unsigned int key_size; unsigned int value_size; unsigned int max_entries; }; #define SEC(NAME) __attribute__((section(NAME), used)) struct bpf_map_def SEC("maps") flip_table = { .type = BPF_MAP_TYPE_ARRAY, .key_size = sizeof(int), .value_size = sizeof(int), .max_entries = 1, }; SEC("func=sys_epoll_pwait") int bpf_func__sys_epoll_pwait(void *ctx) { int ind =0; int *flag = bpf_map_lookup_elem(&flip_table, &ind); int new_flag; if (!flag) return 0; /* flip flag and store back */ new_flag = !*flag; bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY); return new_flag; } char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; ' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o - test child finished with 0 ---- end ---- Test LLVM searching and compiling: Ok [root@zoo wb]# Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-6-git-send-email-wangnan0@huawei.com Signed-off-by: He Kuang <hekuang@huawei.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
49 lines
1.3 KiB
C
49 lines
1.3 KiB
C
/*
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* bpf-script-example.c
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* Test basic LLVM building
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*/
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#ifndef LINUX_VERSION_CODE
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# error Need LINUX_VERSION_CODE
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# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
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#endif
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#define BPF_ANY 0
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#define BPF_MAP_TYPE_ARRAY 2
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#define BPF_FUNC_map_lookup_elem 1
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#define BPF_FUNC_map_update_elem 2
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static void *(*bpf_map_lookup_elem)(void *map, void *key) =
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(void *) BPF_FUNC_map_lookup_elem;
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static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
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(void *) BPF_FUNC_map_update_elem;
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struct bpf_map_def {
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unsigned int type;
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unsigned int key_size;
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unsigned int value_size;
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unsigned int max_entries;
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};
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#define SEC(NAME) __attribute__((section(NAME), used))
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struct bpf_map_def SEC("maps") flip_table = {
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.type = BPF_MAP_TYPE_ARRAY,
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.key_size = sizeof(int),
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.value_size = sizeof(int),
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.max_entries = 1,
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};
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SEC("func=sys_epoll_pwait")
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int bpf_func__sys_epoll_pwait(void *ctx)
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{
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int ind =0;
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int *flag = bpf_map_lookup_elem(&flip_table, &ind);
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int new_flag;
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if (!flag)
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return 0;
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/* flip flag and store back */
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new_flag = !*flag;
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bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY);
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return new_flag;
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}
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char _license[] SEC("license") = "GPL";
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int _version SEC("version") = LINUX_VERSION_CODE;
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