powerpc/perf_counter: Add perf_counter system call on powerpc

... with an empty/dummy asm/perf_counter.h so it builds.
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/include/asm/perf_counter.h

+/*
+ * Performance counter support - PowerPC-specific definitions.
+ *
+ * Copyright 2008-2009 Paul Mackerras, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */

arch/powerpc/include/asm/systbl.h

@@ -322,3 +322,4 @@ SYSCALL_SPU(epoll_create1)
 SYSCALL_SPU(dup3)
 SYSCALL_SPU(pipe2)
 SYSCALL(inotify_init1)
+SYSCALL(perf_counter_open)

arch/powerpc/include/asm/unistd.h

@@ -341,10 +341,11 @@
 #define __NR_dup3		316
 #define __NR_pipe2		317
 #define __NR_inotify_init1	318
+#define __NR_perf_counter_open	319
 
 #ifdef __KERNEL__
 
-#define __NR_syscalls		319
+#define __NR_syscalls		320
 
 #define __NR__exit __NR_exit
 #define NR_syscalls	__NR_syscalls

arch/powerpc/platforms/Kconfig.cputype

 config PPC64
 	bool "64-bit kernel"
 	default n
+	select HAVE_PERF_COUNTERS
 	help
 	  This option selects whether a 32-bit or a 64-bit kernel
 	  will be built.