[tip:perf/core] perf bpf: Add unistd.h to the headers accessible to bpf proggies

[tip-bot for Arnaldo Carvalho de Melo <tipbot@xxxxxxxxx>]

Commit-ID:  1475d35c4a6174d4ec633b9af5713e9770b3ac0d
Gitweb:     https://git.kernel.org/tip/1475d35c4a6174d4ec633b9af5713e9770b3ac0d
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 6 Nov 2018 15:21:45 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 21 Nov 2018 12:00:30 -0300

perf bpf: Add unistd.h to the headers accessible to bpf proggies

Start with a getpid() function wrapping BPF_FUNC_get_current_pid_tgid,
idea is to mimic the system headers.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: https://lkml.kernel.org/n/tip-zo8hv22onidep7tm785dzxfk@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/include/bpf/unistd.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tools/perf/include/bpf/unistd.h b/tools/perf/include/bpf/unistd.h
new file mode 100644
index 000000000000..ca7877f9a976
--- /dev/null
+++ b/tools/perf/include/bpf/unistd.h
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+#include <bpf.h>
+
+static int (*bpf_get_current_pid_tgid)(void) = (void *)BPF_FUNC_get_current_pid_tgid;
+
+static pid_t getpid(void)
+{
+	return bpf_get_current_pid_tgid();
+}