mmu_context.c 1.44 KB
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/* Copyright (C) 2009 Red Hat, Inc.
 *
 * See ../COPYING for licensing terms.
 */

#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/sched/mm.h>
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#include <linux/sched/task.h>
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#include <linux/mmu_context.h>
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#include <linux/export.h>
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#include <linux/ipipe.h>
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#include <asm/mmu_context.h>

/*
 * use_mm
 *	Makes the calling kernel thread take on the specified
 *	mm context.
 *	(Note: this routine is intended to be called only
 *	from a kernel thread context)
 */
void use_mm(struct mm_struct *mm)
{
	struct mm_struct *active_mm;
	struct task_struct *tsk = current;
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	unsigned long flags;
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	task_lock(tsk);
	active_mm = tsk->active_mm;
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 	ipipe_mm_switch_protect(flags);
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	if (active_mm != mm) {
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		mmgrab(mm);
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		tsk->active_mm = mm;
	}
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	tsk->mm = mm;
	switch_mm(active_mm, mm, tsk);
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 	ipipe_mm_switch_unprotect(flags);
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	task_unlock(tsk);
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#ifdef finish_arch_post_lock_switch
	finish_arch_post_lock_switch();
#endif
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	if (active_mm != mm)
		mmdrop(active_mm);
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}
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EXPORT_SYMBOL_GPL(use_mm);
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/*
 * unuse_mm
 *	Reverses the effect of use_mm, i.e. releases the
 *	specified mm context which was earlier taken on
 *	by the calling kernel thread
 *	(Note: this routine is intended to be called only
 *	from a kernel thread context)
 */
void unuse_mm(struct mm_struct *mm)
{
	struct task_struct *tsk = current;

	task_lock(tsk);
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	sync_mm_rss(mm);
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	tsk->mm = NULL;
	/* active_mm is still 'mm' */
	enter_lazy_tlb(mm, tsk);
	task_unlock(tsk);
}
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EXPORT_SYMBOL_GPL(unuse_mm);