x86: Rename global percpu symbol dr7 to cpu_dr7

Percpu symbols now occupy the same namespace as other global
symbols and as such short global symbols without subsystem
prefix tend to collide with local variables.  dr7 percpu
variable used by x86 was hit by this. Rename it to cpu_dr7.

The rename also makes it more consistent with its fellow
cpu_debugreg percpu variable.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20091125115856.GA17856@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>

arch/x86/include/asm/debugreg.h

@@ -75,7 +75,7 @@
  */
 #ifdef __KERNEL__
 
-DECLARE_PER_CPU(unsigned long, dr7);
+DECLARE_PER_CPU(unsigned long, cpu_dr7);
 
 static inline void hw_breakpoint_disable(void)
 {
@@ -91,7 +91,7 @@ static inline void hw_breakpoint_disable(void)
 
 static inline int hw_breakpoint_active(void)
 {
-	return __get_cpu_var(dr7) & DR_GLOBAL_ENABLE_MASK;
+	return __get_cpu_var(cpu_dr7) & DR_GLOBAL_ENABLE_MASK;
 }
 
 extern void aout_dump_debugregs(struct user *dump);

arch/x86/kernel/hw_breakpoint.c

@@ -46,8 +46,8 @@
 #include <asm/debugreg.h>
 
 /* Per cpu debug control register value */
-DEFINE_PER_CPU(unsigned long, dr7);
-EXPORT_PER_CPU_SYMBOL(dr7);
+DEFINE_PER_CPU(unsigned long, cpu_dr7);
+EXPORT_PER_CPU_SYMBOL(cpu_dr7);
 
 /* Per cpu debug address registers values */
 static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]);
@@ -118,7 +118,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
 	set_debugreg(info->address, i);
 	__get_cpu_var(cpu_debugreg[i]) = info->address;
 
-	dr7 = &__get_cpu_var(dr7);
+	dr7 = &__get_cpu_var(cpu_dr7);
 	*dr7 |= encode_dr7(i, info->len, info->type);
 
 	set_debugreg(*dr7, 7);
@@ -153,7 +153,7 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
 	if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot"))
 		return;
 
-	dr7 = &__get_cpu_var(dr7);
+	dr7 = &__get_cpu_var(cpu_dr7);
 	*dr7 &= ~encode_dr7(i, info->len, info->type);
 
 	set_debugreg(*dr7, 7);
@@ -437,7 +437,7 @@ void hw_breakpoint_restore(void)
 	set_debugreg(__get_cpu_var(cpu_debugreg[2]), 2);
 	set_debugreg(__get_cpu_var(cpu_debugreg[3]), 3);
 	set_debugreg(current->thread.debugreg6, 6);
-	set_debugreg(__get_cpu_var(dr7), 7);
+	set_debugreg(__get_cpu_var(cpu_dr7), 7);
 }
 EXPORT_SYMBOL_GPL(hw_breakpoint_restore);