include/asm-ppc64/mmu_context.h

   1 #ifndef __PPC64_MMU_CONTEXT_H
   2 #define __PPC64_MMU_CONTEXT_H
   3
   4 #include <linux/config.h>
   5 #include <linux/kernel.h>
   6 #include <linux/mm.h>
   7 #include <asm/mmu.h>
   8 #include <asm/cputable.h>
   9
  10 /*
  11  * Copyright (C) 2001 PPC 64 Team, IBM Corp
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version
  16  * 2 of the License, or (at your option) any later version.
  17  */
  18
  19 /*
  20  * Getting into a kernel thread, there is no valid user segment, mark
  21  * paca->pgdir NULL so that SLB miss on user addresses will fault
  22  */
  23 static inline void enter_lazy_tlb(struct mm_struct *mm,
  24                                   struct task_struct *tsk)
  25 {
  26 #ifdef CONFIG_PPC_64K_PAGES
  27         get_paca()->pgdir = NULL;
  28 #endif /* CONFIG_PPC_64K_PAGES */
  29 }
  30
  31 #define NO_CONTEXT      0
  32 #define MAX_CONTEXT     (0x100000-1)
  33
  34 extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
  35 extern void destroy_context(struct mm_struct *mm);
  36
  37 extern void switch_stab(struct task_struct *tsk, struct mm_struct *mm);
  38 extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm);
  39
  40 /*
  41  * switch_mm is the entry point called from the architecture independent
  42  * code in kernel/sched.c
  43  */
  44 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  45                              struct task_struct *tsk)
  46 {
  47         if (!cpu_isset(smp_processor_id(), next->cpu_vm_mask))
  48                 cpu_set(smp_processor_id(), next->cpu_vm_mask);
  49
  50         /* No need to flush userspace segments if the mm doesnt change */
  51 #ifdef CONFIG_PPC_64K_PAGES
  52         if (prev == next && get_paca()->pgdir == next->pgd)
  53                 return;
  54 #else
  55         if (prev == next)
  56                 return;
  57 #endif /* CONFIG_PPC_64K_PAGES */
  58
  59 #ifdef CONFIG_ALTIVEC
  60         if (cpu_has_feature(CPU_FTR_ALTIVEC))
  61                 asm volatile ("dssall");
  62 #endif /* CONFIG_ALTIVEC */
  63
  64         if (cpu_has_feature(CPU_FTR_SLB))
  65                 switch_slb(tsk, next);
  66         else
  67                 switch_stab(tsk, next);
  68 }
  69
  70 #define deactivate_mm(tsk,mm)   do { } while (0)
  71
  72 /*
  73  * After we have set current->mm to a new value, this activates
  74  * the context for the new mm so we see the new mappings.
  75  */
  76 static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
  77 {
  78         unsigned long flags;
  79
  80         local_irq_save(flags);
  81         switch_mm(prev, next, current);
  82         local_irq_restore(flags);
  83 }
  84
  85 #endif /* __PPC64_MMU_CONTEXT_H */