コード例 #1
0
ファイル: process.c プロジェクト: Seagate/SMR_FS-EXT4
static void enable_TSC(void)
{
	preempt_disable();
	if (test_and_clear_thread_flag(TIF_NOTSC))
		/*
		 * Must flip the CPU state synchronously with
		 * TIF_NOTSC in the current running context.
		 */
		hard_enable_TSC();
	preempt_enable();
}
コード例 #2
0
ファイル: process.c プロジェクト: AshishNamdev/linux
void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
		      struct tss_struct *tss)
{
	struct thread_struct *prev, *next;

	prev = &prev_p->thread;
	next = &next_p->thread;

	if (test_tsk_thread_flag(prev_p, TIF_BLOCKSTEP) ^
	    test_tsk_thread_flag(next_p, TIF_BLOCKSTEP)) {
		unsigned long debugctl = get_debugctlmsr();

		debugctl &= ~DEBUGCTLMSR_BTF;
		if (test_tsk_thread_flag(next_p, TIF_BLOCKSTEP))
			debugctl |= DEBUGCTLMSR_BTF;

		update_debugctlmsr(debugctl);
	}

	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));

		/*
		 * Make sure that the TSS limit is correct for the CPU
		 * to notice the IO bitmap.
		 */
		refresh_TR();
	} 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);
	}
	propagate_user_return_notify(prev_p, next_p);
}