x86, bts: memory accounting

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / ptrace.c

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 45e9855da2d2812303b52be65a681bff17470df4..0a5df5f82fb9579b1be4e824aa499ac561d9ba10 100644 (file)
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -650,6 +650,24 @@ static int ptrace_bts_drain(struct task_struct *child,
        return drained;
 }
 
+static int ptrace_bts_allocate_buffer(struct task_struct *child, size_t size)
+{
+       child->bts_buffer = alloc_locked_buffer(size);
+       if (!child->bts_buffer)
+               return -ENOMEM;
+
+       child->bts_size = size;
+
+       return 0;
+}
+
+static void ptrace_bts_free_buffer(struct task_struct *child)
+{
+       free_locked_buffer(child->bts_buffer, child->bts_size);
+       child->bts_buffer = NULL;
+       child->bts_size = 0;
+}
+
 static int ptrace_bts_config(struct task_struct *child,
                             long cfg_size,
                             const struct ptrace_bts_config __user *ucfg)
@@ -679,14 +697,13 @@ static int ptrace_bts_config(struct task_struct *child,
 
        if ((cfg.flags & PTRACE_BTS_O_ALLOC) &&
            (cfg.size != child->bts_size)) {
-               kfree(child->bts_buffer);
+               int error;
 
-               child->bts_size = cfg.size;
-               child->bts_buffer = kzalloc(cfg.size, GFP_KERNEL);
-               if (!child->bts_buffer) {
-                       child->bts_size = 0;
-                       return -ENOMEM;
-               }
+               ptrace_bts_free_buffer(child);
+
+               error = ptrace_bts_allocate_buffer(child, cfg.size);
+               if (error < 0)
+                       return error;
        }
 
        if (cfg.flags & PTRACE_BTS_O_TRACE)
@@ -701,10 +718,8 @@ static int ptrace_bts_config(struct task_struct *child,
        if (IS_ERR(child->bts)) {
                int error = PTR_ERR(child->bts);
 
-               kfree(child->bts_buffer);
+               ptrace_bts_free_buffer(child);
                child->bts = NULL;
-               child->bts_buffer = NULL;
-               child->bts_size = 0;
 
                return error;
        }
@@ -769,8 +784,55 @@ static int ptrace_bts_size(struct task_struct *child)
 
        return (trace->ds.top - trace->ds.begin) / trace->ds.size;
 }
+
+static void ptrace_bts_fork(struct task_struct *tsk)
+{
+       tsk->bts = NULL;
+       tsk->bts_buffer = NULL;
+       tsk->bts_size = 0;
+       tsk->thread.bts_ovfl_signal = 0;
+}
+
+static void ptrace_bts_untrace(struct task_struct *child)
+{
+       if (unlikely(child->bts)) {
+               ds_release_bts(child->bts);
+               child->bts = NULL;
+
+               /* We cannot update total_vm and locked_vm since
+                  child's mm is already gone. But we can reclaim the
+                  memory. */
+               kfree(child->bts_buffer);
+               child->bts_buffer = NULL;
+               child->bts_size = 0;
+       }
+}
+
+static void ptrace_bts_detach(struct task_struct *child)
+{
+       if (unlikely(child->bts)) {
+               ds_release_bts(child->bts);
+               child->bts = NULL;
+
+               ptrace_bts_free_buffer(child);
+       }
+}
+#else
+static inline void ptrace_bts_fork(struct task_struct *tsk) {}
+static inline void ptrace_bts_detach(struct task_struct *child) {}
+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..
  *
@@ -782,16 +844,7 @@ void ptrace_disable(struct task_struct *child)
 #ifdef TIF_SYSCALL_EMU
        clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 #endif
-#ifdef CONFIG_X86_PTRACE_BTS
-       if (child->bts) {
-               ds_release_bts(child->bts);
-               child->bts = NULL;
-
-               kfree(child->bts_buffer);
-               child->bts_buffer = NULL;
-               child->bts_size = 0;
-       }
-#endif /* CONFIG_X86_PTRACE_BTS */
+       ptrace_bts_detach(child);
 }
 
 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION