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authorMarkus Metzger <markus.t.metzger@intel.com>2008-01-30 13:31:09 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:31:09 +0100
commiteee3af4a2c83a97fff107ddc445d9df6fded9ce4 (patch)
treea7e9179b82b4df9e4cf6e810c54309324589395b /arch/x86/kernel/process_64.c
parent7796931f542518092d1fd2fb7cf1f1d96e0cd4b5 (diff)
x86, ptrace: support for branch trace store(BTS)
Resend using different mail client Changes to the last version: - split implementation into two layers: ds/bts and ptrace - renamed TIF's - save/restore ds save area msr in __switch_to_xtra() - make block-stepping only look at BTF bit Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/process_64.c')
-rw-r--r--arch/x86/kernel/process_64.c26
1 files changed, 23 insertions, 3 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 057b5442ffd..843bf0c978a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -568,11 +568,21 @@ static inline void __switch_to_xtra(struct task_struct *prev_p,
struct tss_struct *tss)
{
struct thread_struct *prev, *next;
+ unsigned long debugctl;
prev = &prev_p->thread,
next = &next_p->thread;
- if (next->debugctlmsr != prev->debugctlmsr)
+ debugctl = prev->debugctlmsr;
+ if (next->ds_area_msr != prev->ds_area_msr) {
+ /* we clear debugctl to make sure DS
+ * is not in use when we change it */
+ debugctl = 0;
+ wrmsrl(MSR_IA32_DEBUGCTLMSR, 0);
+ wrmsrl(MSR_IA32_DS_AREA, next->ds_area_msr);
+ }
+
+ if (next->debugctlmsr != debugctl)
wrmsrl(MSR_IA32_DEBUGCTLMSR, next->debugctlmsr);
if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
@@ -598,6 +608,16 @@ static inline void __switch_to_xtra(struct task_struct *prev_p,
*/
memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
}
+
+ /*
+ * Last branch recording recofiguration of trace hardware and
+ * disentangling of trace data per task.
+ */
+ 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);
}
/*
@@ -701,8 +721,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/*
* Now maybe reload the debug registers and handle I/O bitmaps
*/
- if (unlikely((task_thread_info(next_p)->flags & _TIF_WORK_CTXSW))
- || test_tsk_thread_flag(prev_p, TIF_IO_BITMAP))
+ if (unlikely(task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT ||
+ task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
__switch_to_xtra(prev_p, next_p, tss);
/* If the task has used fpu the last 5 timeslices, just do a full