1 files changed, 16 insertions, 51 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 0a1302fe6d45..3ba155d24884 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -38,6 +38,7 @@
 #include <linux/percpu.h>
 #include <linux/prctl.h>
 #include <linux/dmi.h>
+#include <linux/ftrace.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -59,6 +60,7 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/smp.h>
+#include <asm/ds.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -250,14 +252,8 @@ void exit_thread(void)
                 tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
                 put_cpu();
         }
-#ifdef CONFIG_X86_DS
-        /* Free any DS contexts that have not been properly released. */
-        if (unlikely(current->thread.ds_ctx)) {
-                /* we clear debugctl to make sure DS is not used. */
-                update_debugctlmsr(0);
-                ds_free(current->thread.ds_ctx);
-        }
-#endif /* CONFIG_X86_DS */
+
+        ds_exit_thread(current);
 }
 
 void flush_thread(void)
@@ -339,6 +335,12 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
                 kfree(p->thread.io_bitmap_ptr);
                 p->thread.io_bitmap_max = 0;
         }
+
+        ds_copy_thread(p, current);
+
+        clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
+        p->thread.debugctlmsr = 0;
+
         return err;
 }
 
@@ -419,48 +421,19 @@ int set_tsc_mode(unsigned int val)
         return 0;
 }
 
-#ifdef CONFIG_X86_DS
-static int update_debugctl(struct thread_struct *prev,
-                        struct thread_struct *next, unsigned long debugctl)
-{
-        unsigned long ds_prev = 0;
-        unsigned long ds_next = 0;
-
-        if (prev->ds_ctx)
-                ds_prev = (unsigned long)prev->ds_ctx->ds;
-        if (next->ds_ctx)
-                ds_next = (unsigned long)next->ds_ctx->ds;
-
-        if (ds_next != ds_prev) {
-                /* we clear debugctl to make sure DS
-                 * is not in use when we change it */
-                debugctl = 0;
-                update_debugctlmsr(0);
-                wrmsr(MSR_IA32_DS_AREA, ds_next, 0);
-        }
-        return debugctl;
-}
-#else
-static int update_debugctl(struct thread_struct *prev,
-                        struct thread_struct *next, unsigned long debugctl)
-{
-        return debugctl;
-}
-#endif /* CONFIG_X86_DS */
-
 static noinline void
 __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
                  struct tss_struct *tss)
 {
         struct thread_struct *prev, *next;
-        unsigned long debugctl;
 
         prev = &prev_p->thread;
         next = &next_p->thread;
 
-        debugctl = update_debugctl(prev, next, prev->debugctlmsr);
-
-        if (next->debugctlmsr != debugctl)
+        if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||
+            test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))
+                ds_switch_to(prev_p, next_p);
+        else if (next->debugctlmsr != prev->debugctlmsr)
                 update_debugctlmsr(next->debugctlmsr);
 
         if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
@@ -482,15 +455,6 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
                         hard_enable_TSC();
         }
 
-#ifdef CONFIG_X86_PTRACE_BTS
-        if (test_tsk_thread_flag(prev_p, TIF_BTS_TRACE_TS))
-                ptrace_bts_take_timestamp(prev_p, BTS_TASK_DEPARTS);
-
-        if (test_tsk_thread_flag(next_p, TIF_BTS_TRACE_TS))
-                ptrace_bts_take_timestamp(next_p, BTS_TASK_ARRIVES);
-#endif /* CONFIG_X86_PTRACE_BTS */
-
-
         if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
                 /*
                  * Disable the bitmap via an invalid offset. We still cache
@@ -548,7 +512,8 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
  * the task-switch, and shows up in ret_from_fork in entry.S,
  * for example.
  */
-struct task_struct * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
+__notrace_funcgraph struct task_struct *
+__switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 {
         struct thread_struct *prev = &prev_p->thread,
                                  *next = &next_p->thread;