hw-breakpoints: use wrapper routines around debug registers in processor related functions

This patch enables the use of wrapper routines to access the debug/breakpoint
registers on cpu management.

The hardcoded debug registers save and restore operations for threads
breakpoints are replaced by wrappers.

And now that we handle the kernel breakpoints too, we also need to handle them
on cpu hotplug operations.

[ Impact: adapt new hardware breakpoint api to cpu hotplug ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

arch/x86/kernel/smpboot.c

@@ -63,6 +63,7 @@
 #include <asm/apic.h>
 #include <asm/setup.h>
 #include <asm/uv/uv.h>
+#include <asm/debugreg.h>
 #include <linux/mc146818rtc.h>
 
 #include <asm/smpboot_hooks.h>
@@ -326,6 +327,7 @@ notrace static void __cpuinit start_secondary(void *unused)
 	setup_secondary_clock();
 
 	wmb();
+	load_debug_registers();
 	cpu_idle();
 }
 
@@ -1250,6 +1252,7 @@ void cpu_disable_common(void)
 	remove_cpu_from_maps(cpu);
 	unlock_vector_lock();
 	fixup_irqs();
+	hw_breakpoint_disable();
 }
 
 int native_cpu_disable(void)

arch/x86/power/cpu_32.c

@@ -13,6 +13,7 @@
 #include <asm/mce.h>
 #include <asm/xcr.h>
 #include <asm/suspend.h>
+#include <asm/debugreg.h>
 
 static struct saved_context saved_context;
 
@@ -48,6 +49,7 @@ static void __save_processor_state(struct saved_context *ctxt)
 	ctxt->cr2 = read_cr2();
 	ctxt->cr3 = read_cr3();
 	ctxt->cr4 = read_cr4_safe();
+	hw_breakpoint_disable();
 }
 
 /* Needed by apm.c */
@@ -83,16 +85,7 @@ static void fix_processor_context(void)
 	/*
 	 * Now maybe reload the debug registers
 	 */
-	if (current->thread.debugreg7) {
-		set_debugreg(current->thread.debugreg[0], 0);
-		set_debugreg(current->thread.debugreg[1], 1);
-		set_debugreg(current->thread.debugreg[2], 2);
-		set_debugreg(current->thread.debugreg[3], 3);
-		/* no 4 and 5 */
-		set_debugreg(current->thread.debugreg6, 6);
-		set_debugreg(current->thread.debugreg7, 7);
-	}
-
+	load_debug_registers();
 }
 
 static void __restore_processor_state(struct saved_context *ctxt)

arch/x86/power/cpu_64.c

@@ -16,6 +16,7 @@
 #include <asm/mtrr.h>
 #include <asm/xcr.h>
 #include <asm/suspend.h>
+#include <asm/debugreg.h>
 
 static void fix_processor_context(void);
 
@@ -71,6 +72,7 @@ static void __save_processor_state(struct saved_context *ctxt)
 	ctxt->cr3 = read_cr3();
 	ctxt->cr4 = read_cr4();
 	ctxt->cr8 = read_cr8();
+	hw_breakpoint_disable();
 }
 
 void save_processor_state(void)
@@ -162,13 +164,5 @@ static void fix_processor_context(void)
 	/*
 	 * Now maybe reload the debug registers
 	 */
-	if (current->thread.debugreg7){
-		set_debugreg(current->thread.debugreg[0], 0);
-		set_debugreg(current->thread.debugreg[1], 1);
-		set_debugreg(current->thread.debugreg[2], 2);
-		set_debugreg(current->thread.debugreg[3], 3);
-                /* no 4 and 5 */
-                loaddebug(&current->thread, 6);
-                loaddebug(&current->thread, 7);
-	}
+	load_debug_registers();
 }