[PATCH] xen: x86_64: Add macro for debugreg

Add 2 macros to set and get debugreg on x86_64.  This is useful for Xen
because it will need only to redefine each macro to a hypervisor call.

Signed-off-by: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 11 insertions, 3 deletions

diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c
index 3c5f30893715..0446e8b96a20 100644
--- a/arch/x86_64/kernel/signal.c
+++ b/arch/x86_64/kernel/signal.c
@@ -439,7 +439,7 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset)
                  * inside the kernel.
                  */
                 if (current->thread.debugreg7)
-                        asm volatile("movq %0,%%db7"    : : "r" (current->thread.debugreg7));
+                        set_debugreg(current->thread.debugreg7, 7);
 
                 /* Whee!  Actually deliver the signal.  */
                 return handle_signal(signr, &info, &ka, oldset, regs);
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 3dfec8fdabcd..21706c1a0f95 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -669,7 +669,7 @@ asmlinkage void do_debug(struct pt_regs * regs, unsigned long error_code)
        }
 #endif
 
-        asm("movq %%db6,%0" : "=r" (condition));
+        get_debugreg(condition, 6);
 
         if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
                                                 SIGTRAP) == NOTIFY_STOP)
@@ -721,7 +721,7 @@ asmlinkage void do_debug(struct pt_regs * regs, unsigned long error_code)
         info.si_addr = (void __user *)regs->rip;
         force_sig_info(SIGTRAP, &info, tsk);    
 clear_dr7:
-        asm volatile("movq %0,%%db7"::"r"(0UL));
+        set_debugreg(0UL, 7);
         return;
 
 clear_TF_reenable:
diff --git a/include/asm-x86_64/processor.h b/include/asm-x86_64/processor.h
index 8b55f139968f..106f666517bb 100644
--- a/include/asm-x86_64/processor.h
+++ b/include/asm-x86_64/processor.h
@@ -280,6 +280,14 @@ struct thread_struct {
         set_fs(USER_DS);                                                         \
 } while(0) 
 
+#define get_debugreg(var, register)                             \
+                __asm__("movq %%db" #register ", %0"            \
+                        :"=r" (var))
+#define set_debugreg(value, register)                   \
+                __asm__("movq %0,%%db" #register                \
+                        : /* no output */                       \
+                        :"r" (value))
+
 struct task_struct;
 struct mm_struct;