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Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-64: move clts into batch cpu state updates when preloading fpu
  x86-64: move unlazy_fpu() into lazy cpu state part of context switch
  x86-32: make sure clts is batched during context switch
  x86: split out core __math_state_restore
This commit is contained in:
Linus Torvalds
2009-09-14 07:58:08 -07:00
parent 8fafa0a789 17950c5b24
commit 625037cc40
4 changed files with 61 additions and 33 deletions
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33
arch/x86/kernel/traps.c
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@@ -794,6 +794,28 @@ asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
{
}
/*
* __math_state_restore assumes that cr0.TS is already clear and the
* fpu state is all ready for use. Used during context switch.
*/
void __math_state_restore(void)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = thread->task;
/*
* Paranoid restore. send a SIGSEGV if we fail to restore the state.
*/
if (unlikely(restore_fpu_checking(tsk))) {
stts();
force_sig(SIGSEGV, tsk);
return;
}
thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
tsk->fpu_counter++;
}
/*
* 'math_state_restore()' saves the current math information in the
* old math state array, and gets the new ones from the current task
@@ -825,17 +847,8 @@ asmlinkage void math_state_restore(void)
}
clts(); /* Allow maths ops (or we recurse) */
/*
* Paranoid restore. send a SIGSEGV if we fail to restore the state.
*/
if (unlikely(restore_fpu_checking(tsk))) {
stts();
force_sig(SIGSEGV, tsk);
return;
}
thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
tsk->fpu_counter++;
__math_state_restore();
}
EXPORT_SYMBOL_GPL(math_state_restore);