-
-/*
- * This special macro can be used to load a debugging register
- */
-#define loaddebug(thread, r) set_debugreg(thread->debugreg ## r, r)
-
-static inline 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 = 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;
- update_debugctlmsr(0);
- wrmsrl(MSR_IA32_DS_AREA, next->ds_area_msr);
- }
-
- if (next->debugctlmsr != debugctl)
- update_debugctlmsr(next->debugctlmsr);
-
- if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
- loaddebug(next, 0);
- loaddebug(next, 1);
- loaddebug(next, 2);
- loaddebug(next, 3);
- /* no 4 and 5 */
- loaddebug(next, 6);
- loaddebug(next, 7);
- }
-
- if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
- test_tsk_thread_flag(next_p, TIF_NOTSC)) {
- /* prev and next are different */
- if (test_tsk_thread_flag(next_p, TIF_NOTSC))
- hard_disable_TSC();
- else
- hard_enable_TSC();
- }
-
- if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
- /*
- * Copy the relevant range of the IO bitmap.
- * Normally this is 128 bytes or less:
- */
- memcpy(tss->io_bitmap, next->io_bitmap_ptr,
- max(prev->io_bitmap_max, next->io_bitmap_max));
- } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {
- /*
- * Clear any possible leftover bits:
- */
- memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
- }
-
-#ifdef X86_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);