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x86, ptrace: support for branch trace store(BTS)

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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>
This commit is contained in:
Markus Metzger
2008-01-30 13:31:09 +01:00
committed by Ingo Molnar
parent 7796931f54
commit eee3af4a2c
16 changed files with 859 additions and 12 deletions
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19
arch/x86/kernel/process_32.c
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@ -614,11 +614,21 @@ __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;
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);
wrmsr(MSR_IA32_DS_AREA, next->ds_area_msr, 0);
}
if (next->debugctlmsr != debugctl)
wrmsr(MSR_IA32_DEBUGCTLMSR, next->debugctlmsr, 0);
if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
@ -642,6 +652,13 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
}
#endif
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);
if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
/*
* Disable the bitmap via an invalid offset. We still cache