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 <[email protected]> Cc: David Ahern <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Wang Nan <[email protected]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
chewitt · Jul 12, 2016 · c7007e9 · c7007e9
1 parent 4998a12
commit c7007e9
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Showing 4 changed files with 20 additions and 4 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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 */