1 /* Copyright (C) 2009 Red Hat, Inc. 2 * 3 * See ../COPYING for licensing terms. 4 */ 5 6 #include <linux/mm.h> 7 #include <linux/sched.h> 8 #include <linux/sched/mm.h> 9 #include <linux/sched/task.h> 10 #include <linux/mmu_context.h> 11 #include <linux/export.h> 12 13 #include <asm/mmu_context.h> 14 15 /* 16 * use_mm 17 * Makes the calling kernel thread take on the specified 18 * mm context. 19 * (Note: this routine is intended to be called only 20 * from a kernel thread context) 21 */ use_mm(struct mm_struct * mm)22void use_mm(struct mm_struct *mm) 23 { 24 struct mm_struct *active_mm; 25 struct task_struct *tsk = current; 26 27 task_lock(tsk); 28 /* Hold off tlb flush IPIs while switching mm's */ 29 local_irq_disable(); 30 active_mm = tsk->active_mm; 31 if (active_mm != mm) { 32 mmgrab(mm); 33 tsk->active_mm = mm; 34 } 35 tsk->mm = mm; 36 switch_mm_irqs_off(active_mm, mm, tsk); 37 local_irq_enable(); 38 task_unlock(tsk); 39 #ifdef finish_arch_post_lock_switch 40 finish_arch_post_lock_switch(); 41 #endif 42 43 if (active_mm != mm) 44 mmdrop(active_mm); 45 } 46 EXPORT_SYMBOL_GPL(use_mm); 47 48 /* 49 * unuse_mm 50 * Reverses the effect of use_mm, i.e. releases the 51 * specified mm context which was earlier taken on 52 * by the calling kernel thread 53 * (Note: this routine is intended to be called only 54 * from a kernel thread context) 55 */ unuse_mm(struct mm_struct * mm)56void unuse_mm(struct mm_struct *mm) 57 { 58 struct task_struct *tsk = current; 59 60 task_lock(tsk); 61 sync_mm_rss(mm); 62 local_irq_disable(); 63 tsk->mm = NULL; 64 /* active_mm is still 'mm' */ 65 enter_lazy_tlb(mm, tsk); 66 local_irq_enable(); 67 task_unlock(tsk); 68 } 69 EXPORT_SYMBOL_GPL(unuse_mm); 70