[PATCH] make cpu_relax a barrier on all architectures

Make cpu_relax() on all architectures a gcc barrier to match x86.

include/asm-alpha/processor.h

@@ -74,7 +74,7 @@ unsigned long get_wchan(struct task_struct *p);
 #define KSTK_ESP(tsk) \
   ((tsk) == current ? rdusp() : (tsk)->thread_info->pcb.usp)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 #define ARCH_HAS_PREFETCH
 #define ARCH_HAS_PREFETCHW

include/asm-arm/processor.h

@@ -59,7 +59,7 @@ extern void release_thread(struct task_struct *);
 
 unsigned long get_wchan(struct task_struct *p);
 
-#define cpu_relax()			do { } while (0)
+#define cpu_relax()			barrier()
 
 /*
  * Create a new kernel thread

include/asm-cris/processor.h

@@ -142,6 +142,6 @@ extern inline unsigned long thread_saved_pc(struct thread_struct *t)
 #define init_task       (init_task_union.task)
 #define init_stack      (init_task_union.stack)
 
-#define cpu_relax()     do { } while (0)
+#define cpu_relax()     barrier()
 
 #endif /* __ASM_CRIS_PROCESSOR_H */

include/asm-ia64/processor.h

@@ -616,7 +616,7 @@ ia64_set_lrr0 (unsigned long val)
 	asm volatile ("mov cr.lrr0=%0;; srlz.d" :: "r"(val) : "memory");
 }
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 
 static inline void

include/asm-m68k/processor.h

@@ -137,6 +137,6 @@ unsigned long get_wchan(struct task_struct *p);
 	eip; })
 #define	KSTK_ESP(tsk)	((tsk) == current ? rdusp() : (tsk)->thread.usp)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 #endif

include/asm-mips/processor.h

@@ -259,7 +259,7 @@ unsigned long get_wchan(struct task_struct *p);
 #define init_task	(init_task_union.task)
 #define init_stack	(init_task_union.stack)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 #endif /* !defined (_LANGUAGE_ASSEMBLY) */
 #endif /* __KERNEL__ */

include/asm-mips64/processor.h

@@ -290,7 +290,7 @@ unsigned long get_wchan(struct task_struct *p);
 #define init_task	(init_task_union.task)
 #define init_stack	(init_task_union.stack)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 #endif /* !defined (_LANGUAGE_ASSEMBLY) */
 #endif /* __KERNEL__ */

include/asm-parisc/processor.h

@@ -333,7 +333,7 @@ extern inline unsigned long get_wchan(struct task_struct *p)
 #define init_task (init_task_union.task) 
 #define init_stack (init_task_union.stack)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 
 #endif /* __ASM_PARISC_PROCESSOR_H */

include/asm-ppc/processor.h

@@ -771,7 +771,7 @@ void _nmask_and_or_msr(unsigned long nmask, unsigned long or_val);
 
 #define have_of (_machine == _MACH_chrp || _machine == _MACH_Pmac)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 /*
  * Prefetch macros.

include/asm-ppc64/processor.h

@@ -692,7 +692,7 @@ unsigned long get_wchan(struct task_struct *p);
 #define KSTK_EIP(tsk)  ((tsk)->thread.regs? (tsk)->thread.regs->nip: 0)
 #define KSTK_ESP(tsk)  ((tsk)->thread.regs? (tsk)->thread.regs->gpr[1]: 0)
 
-#define cpu_relax()     do { } while (0)
+#define cpu_relax()     barrier()
 
 /*
  * Prefetch macros.

include/asm-s390/processor.h

@@ -134,7 +134,7 @@ unsigned long get_wchan(struct task_struct *p);
 #define KSTK_EIP(tsk)	(__KSTK_PTREGS(tsk)->psw.addr)
 #define KSTK_ESP(tsk)	(__KSTK_PTREGS(tsk)->gprs[15])
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 /*
  * Set of msr bits that gdb can change on behalf of a process.

include/asm-s390x/processor.h

@@ -151,7 +151,7 @@ unsigned long get_wchan(struct task_struct *p);
 #define KSTK_EIP(tsk)	(__KSTK_PTREGS(tsk)->psw.addr)
 #define KSTK_ESP(tsk)	(__KSTK_PTREGS(tsk)->gprs[15])
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 /*
  * Set of msr bits that gdb can change on behalf of a process.

include/asm-sh/processor.h

@@ -222,6 +222,6 @@ extern void free_task_struct(struct task_struct *);
 #define init_task	(init_task_union.task)
 #define init_stack	(init_task_union.stack)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 #endif /* __ASM_SH_PROCESSOR_H */

include/asm-sparc/processor.h

@@ -201,7 +201,7 @@ BTFIXUPDEF_CALL(void, get_task_struct, struct task_struct *)
 #define init_task	(init_task_union.task)
 #define init_stack	(init_task_union.stack)
 
-#define cpu_relax()	do { } while (0)
+#define cpu_relax()	barrier()
 
 #endif
 

include/asm-sparc64/processor.h

@@ -225,7 +225,7 @@ __out:	__ret; \
 #define KSTK_EIP(tsk)  ((tsk)->thread_info->kregs->tpc)
 #define KSTK_ESP(tsk)  ((tsk)->thread_info->kregs->u_regs[UREG_FP])
 
-#define cpu_relax()	udelay(1 + smp_processor_id())
+#define cpu_relax()	do { udelay(1 + smp_processor_id()); barrier(); } while  (0)
 
 #endif /* !(__ASSEMBLY__) */
 

include/asm-x86_64/processor.h

@@ -367,7 +367,7 @@ extern unsigned long get_wchan(struct task_struct *p);
 /* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
 extern inline void rep_nop(void)
 {
-	__asm__ __volatile__("rep;nop");
+	__asm__ __volatile__("rep;nop": : :"memory");
 }
 
 #define cpu_has_fpu 1