hw-breakpoints: use the new wrapper routines to access debug registers in process/thread code

This patch enables the use of abstract debug registers in
process-handling routines, according to the new hardware breakpoint
Api.

[ Impact: adapt thread breakpoints handling code to the new breakpoint Api ]

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>

1 files changed, 6 insertions, 16 deletions

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 291527cb438a..19a686c401b5 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -15,6 +15,8 @@
 #include <asm/uaccess.h>
 #include <asm/i387.h>
 #include <asm/ds.h>
+#include <asm/debugreg.h>
+#include <asm/hw_breakpoint.h>
 
 unsigned long idle_halt;
 EXPORT_SYMBOL(idle_halt);
@@ -46,6 +48,8 @@ void free_thread_xstate(struct task_struct *tsk)
                 kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
                 tsk->thread.xstate = NULL;
         }
+        if (unlikely(test_tsk_thread_flag(tsk, TIF_DEBUG)))
+                flush_thread_hw_breakpoint(tsk);
 
         WARN(tsk->thread.ds_ctx, "leaking DS context\n");
 }
@@ -106,12 +110,8 @@ void flush_thread(void)
 
         clear_tsk_thread_flag(tsk, TIF_DEBUG);
 
-        tsk->thread.debugreg[0] = 0;
-        tsk->thread.debugreg[1] = 0;
-        tsk->thread.debugreg[2] = 0;
-        tsk->thread.debugreg[3] = 0;
-        tsk->thread.debugreg6 = 0;
-        tsk->thread.debugreg7 = 0;
+        if (unlikely(test_tsk_thread_flag(tsk, TIF_DEBUG)))
+                flush_thread_hw_breakpoint(tsk);
         memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
         /*
          * Forget coprocessor state..
@@ -193,16 +193,6 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
         else if (next->debugctlmsr != prev->debugctlmsr)
                 update_debugctlmsr(next->debugctlmsr);
 
-        if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
-                set_debugreg(next->debugreg[0], 0);
-                set_debugreg(next->debugreg[1], 1);
-                set_debugreg(next->debugreg[2], 2);
-                set_debugreg(next->debugreg[3], 3);
-                /* no 4 and 5 */
-                set_debugreg(next->debugreg6, 6);
-                set_debugreg(next->debugreg7, 7);
-        }
-
         if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
             test_tsk_thread_flag(next_p, TIF_NOTSC)) {
                 /* prev and next are different */