x86, ptrace: add bts context unconditionally

Add the ptrace bts context field to task_struct unconditionally.

Initialize the field directly in copy_process().
Remove all the unneeded functionality used to initialize that field.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Cc: roland@redhat.com
Cc: eranian@googlemail.com
Cc: oleg@redhat.com
Cc: juan.villacis@intel.com
Cc: ak@linux.jf.intel.com
LKML-Reference: <20090403144603.292754000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

6 files changed, 7 insertions, 48 deletions

diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index e304b66abeea..5cdd19f20b5b 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -235,12 +235,11 @@ extern int do_get_thread_area(struct task_struct *p, int idx,
 extern int do_set_thread_area(struct task_struct *p, int idx,
                               struct user_desc __user *info, int can_allocate);
 
-extern void x86_ptrace_untrace(struct task_struct *);
-extern void x86_ptrace_fork(struct task_struct *child,
-                            unsigned long clone_flags);
+#ifdef CONFIG_X86_PTRACE_BTS
+extern void ptrace_bts_untrace(struct task_struct *tsk);
 
-#define arch_ptrace_untrace(tsk) x86_ptrace_untrace(tsk)
-#define arch_ptrace_fork(child, flags) x86_ptrace_fork(child, flags)
+#define arch_ptrace_untrace(tsk)        ptrace_bts_untrace(tsk)
+#endif /* CONFIG_X86_PTRACE_BTS */
 
 #endif /* __KERNEL__ */
 
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index adbb24322d8f..b32a8ee53381 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -887,37 +887,19 @@ static int ptrace_bts_size(struct task_struct *child)
         return (trace->ds.top - trace->ds.begin) / trace->ds.size;
 }
 
-static inline void ptrace_bts_fork(struct task_struct *tsk)
-{
-        tsk->bts = NULL;
-}
-
 /*
  * Called from __ptrace_unlink() after the child has been moved back
  * to its original parent.
  */
-static inline void ptrace_bts_untrace(struct task_struct *child)
+void ptrace_bts_untrace(struct task_struct *child)
 {
         if (unlikely(child->bts)) {
                 free_bts_context(child->bts);
                 child->bts = NULL;
         }
 }
-#else
-static inline void ptrace_bts_fork(struct task_struct *tsk) {}
-static inline void ptrace_bts_untrace(struct task_struct *child) {}
 #endif /* CONFIG_X86_PTRACE_BTS */
 
-void x86_ptrace_fork(struct task_struct *child, unsigned long clone_flags)
-{
-        ptrace_bts_fork(child);
-}
-
-void x86_ptrace_untrace(struct task_struct *child)
-{
-        ptrace_bts_untrace(child);
-}
-
 /*
  * Called by kernel/ptrace.c when detaching..
  *
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 67c15653fc23..59e133d39d50 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -95,7 +95,6 @@ extern void __ptrace_link(struct task_struct *child,
                           struct task_struct *new_parent);
 extern void __ptrace_unlink(struct task_struct *child);
 extern void exit_ptrace(struct task_struct *tracer);
-extern void ptrace_fork(struct task_struct *task, unsigned long clone_flags);
 #define PTRACE_MODE_READ   1
 #define PTRACE_MODE_ATTACH 2
 /* Returns 0 on success, -errno on denial. */
@@ -327,15 +326,6 @@ static inline void user_enable_block_step(struct task_struct *task)
 #define arch_ptrace_untrace(task)               do { } while (0)
 #endif
 
-#ifndef arch_ptrace_fork
-/*
- * Do machine-specific work to initialize a new task.
- *
- * This is called from copy_process().
- */
-#define arch_ptrace_fork(child, clone_flags)    do { } while (0)
-#endif
-
 extern int task_current_syscall(struct task_struct *target, long *callno,
                                 unsigned long args[6], unsigned int maxargs,
                                 unsigned long *sp, unsigned long *pc);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 52b8cd049c2e..451186a22ef5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1205,13 +1205,11 @@ struct task_struct {
         struct list_head ptraced;
         struct list_head ptrace_entry;
 
-#ifdef CONFIG_X86_PTRACE_BTS
         /*
          * This is the tracer handle for the ptrace BTS extension.
          * This field actually belongs to the ptracer task.
          */
         struct bts_context *bts;
-#endif /* CONFIG_X86_PTRACE_BTS */
 
         /* PID/PID hash table linkage. */
         struct pid_link pids[PIDTYPE_MAX];
diff --git a/kernel/fork.c b/kernel/fork.c
index 660c2b8765bc..69bde7a22e9b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1086,8 +1086,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 #ifdef CONFIG_DEBUG_MUTEXES
         p->blocked_on = NULL; /* not blocked yet */
 #endif
-        if (unlikely(current->ptrace))
-                ptrace_fork(p, clone_flags);
+
+        p->bts = NULL;
 
         /* Perform scheduler related setup. Assign this task to a CPU. */
         sched_fork(p, clone_flags);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index aaad0ec34194..321127d965c2 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -27,16 +27,6 @@
 
 
 /*
- * Initialize a new task whose father had been ptraced.
- *
- * Called from copy_process().
- */
-void ptrace_fork(struct task_struct *child, unsigned long clone_flags)
-{
-        arch_ptrace_fork(child, clone_flags);
-}
-
-/*
  * ptrace a task: make the debugger its new parent and
  * move it to the ptrace list.
  *