[tip:perf/core] perf tools: Introduce weak alternative to sched_getcpu()

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  c7007e983682b31d91e9ad7c3e85c49ffcc3651f
Gitweb:     http://git.kernel.org/tip/c7007e983682b31d91e9ad7c3e85c49ffcc3651f
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 12 Jul 2016 10:29:31 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 12 Jul 2016 15:20:34 -0300

perf tools: Introduce weak alternative to sched_getcpu()

Which is just a wrapper for sys_getcpu and is not present in at least
musl libc.

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: http://lkml.kernel.org/n/tip-kblef7svmhr0g93kkx78envg@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/arch/x86/include/asm/unistd_32.h |  3 +++
 tools/arch/x86/include/asm/unistd_64.h |  3 +++
 tools/perf/util/cloexec.c              | 14 ++++++++++----
 tools/perf/util/util.h                 |  4 ++++
 4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/tools/arch/x86/include/asm/unistd_32.h b/tools/arch/x86/include/asm/unistd_32.h
index cf33ab0..88b3f8c 100644
--- a/tools/arch/x86/include/asm/unistd_32.h
+++ b/tools/arch/x86/include/asm/unistd_32.h
@@ -7,3 +7,6 @@
 #ifndef __NR_gettid
 # define __NR_gettid 224
 #endif
+#ifndef __NR_getcpu
+# define __NR_getcpu 318
+#endif
diff --git a/tools/arch/x86/include/asm/unistd_64.h b/tools/arch/x86/include/asm/unistd_64.h
index 2c98356..fbdb70e 100644
--- a/tools/arch/x86/include/asm/unistd_64.h
+++ b/tools/arch/x86/include/asm/unistd_64.h
@@ -7,3 +7,6 @@
 #ifndef __NR_gettid
 # define __NR_gettid 186
 #endif
+#ifndef __NR_getcpu
+# define __NR_getcpu 309
+#endif
diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
index fde772d..f0dcd0e 100644
--- a/tools/perf/util/cloexec.c
+++ b/tools/perf/util/cloexec.c
@@ -4,18 +4,24 @@
 #include "cloexec.h"
 #include "asm/bug.h"
 #include "debug.h"
+#include <unistd.h>
+#include <asm/unistd.h>
+#include <sys/syscall.h>
 
 static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
 
-#ifdef __GLIBC_PREREQ
-#if !__GLIBC_PREREQ(2, 6)
 int __weak sched_getcpu(void)
 {
+#ifdef __NR_getcpu
+	unsigned cpu;
+	int err = syscall(__NR_getcpu, &cpu, NULL, NULL);
+	if (!err)
+		return cpu;
+#else
 	errno = ENOSYS;
+#endif
 	return -1;
 }
-#endif
-#endif
 
 static int perf_flag_probe(void)
 {
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 2370cfb..d8d41ef 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -361,4 +361,8 @@ void print_binary(unsigned char *data, size_t len,
 		  size_t bytes_per_line, print_binary_t printer,
 		  void *extra);
 
+#ifndef __GLIBC__
+extern int sched_getcpu(void);
+#endif
+
 #endif /* GIT_COMPAT_UTIL_H */