Arnaldo Carvalho de Melo 822c2621da perf bpf: Include uapi/linux/bpf.h from the 'perf trace' script's bpf.h ... The next example scripts need the definition for the BPF functions, i.e. things like BPF_FUNC_probe_read, and in time will require lots of other definitions found in uapi/linux/bpf.h, so include it from the bpf.h file included from the eBPF scripts build with clang via '-e bpf_script.c' like in this example: $ tail -8 tools/perf/examples/bpf/5sec.c #include <bpf.h> int probe(hrtimer_nanosleep, rqtp->tv_sec)(void *ctx, int err, long sec) { return sec == 5; } license(GPL); $ That 'bpf.h' include in the 5sec.c eBPF example will come from a set of header files crafted for building eBPF objects, that in a end-user system will come from: /usr/lib/perf/include/bpf/bpf.h And will include <uapi/linux/bpf.h> either from the place where the kernel was built, or from a kernel-devel rpm package like: -working-directory /lib/modules/4.17.9-100.fc27.x86_64/build That is set up by tools/perf/util/llvm-utils.c, and can be overriden by setting the 'kbuild-dir' variable in the "llvm" ~/.perfconfig file, like: # cat ~/.perfconfig [llvm] kbuild-dir = /home/foo/git/build/linux This usually doesn't need any change, just documenting here my findings while working with this code. In the future we may want to instead just use what is in /usr/include/linux/bpf.h, that comes from the UAPI provided from the kernel sources, for now, to avoid getting the kernel's non-UAPI "linux/bpf.h" file, that will cause clang to fail and is not what we want anyway (no BPF function definitions, etc), do it explicitely by asking for "uapi/linux/bpf.h". 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-zd8zeyhr2sappevojdem9xxt@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>		2018-08-01 12:34:06 -03:00
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bpf.h	perf bpf: Include uapi/linux/bpf.h from the 'perf trace' script's bpf.h	2018-08-01 12:34:06 -03:00