x86, bts: provide in-kernel branch-trace interface

[safe/jmp/linux-2.6] / arch / x86 / kernel / process_32.c

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 24c2276..605eff9 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -252,11 +252,14 @@ void exit_thread(void)
                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);
+       /* Free any BTS tracers that have not been properly released. */
+       if (unlikely(current->bts)) {
+               ds_release_bts(current->bts);
+               current->bts = NULL;
+
+               kfree(current->bts_buffer);
+               current->bts_buffer = NULL;
+               current->bts_size = 0;
        }
 #endif /* CONFIG_X86_DS */
 }
@@ -420,48 +423,19 @@ 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)) {
@@ -483,15 +457,6 @@ __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