LXR linux/arch/s390/include/asm/mmu

   1/*
   2 *  S390 version
   3 *
   4 *  Derived from "include/asm-i386/mmu_context.h"
   5 */
   6
   7#ifndef __S390_MMU_CONTEXT_H
   8#define __S390_MMU_CONTEXT_H
   9
  10#include <asm/pgalloc.h>
  11#include <linux/uaccess.h>
  12#include <linux/mm_types.h>
  13#include <asm/tlbflush.h>
  14#include <asm/ctl_reg.h>
  15
  16static inline int init_new_context(struct task_struct *tsk,
  17                                   struct mm_struct *mm)
  18{
  19        spin_lock_init(&mm->context.pgtable_lock);
  20        INIT_LIST_HEAD(&mm->context.pgtable_list);
  21        spin_lock_init(&mm->context.gmap_lock);
  22        INIT_LIST_HEAD(&mm->context.gmap_list);
  23        cpumask_clear(&mm->context.cpu_attach_mask);
  24        atomic_set(&mm->context.flush_count, 0);
  25        mm->context.gmap_asce = 0;
  26        mm->context.flush_mm = 0;
  27#ifdef CONFIG_PGSTE
  28        mm->context.alloc_pgste = page_table_allocate_pgste ||
  29                test_thread_flag(TIF_PGSTE) ||
  30                current->mm->context.alloc_pgste;
  31        mm->context.has_pgste = 0;
  32        mm->context.use_skey = 0;
  33        mm->context.use_cmma = 0;
  34#endif
  35        switch (mm->context.asce_limit) {
  36        case 1UL << 42:
  37                /*
  38                 * forked 3-level task, fall through to set new asce with new
  39                 * mm->pgd
  40                 */
  41        case 0:
  42                /* context created by exec, set asce limit to 4TB */
  43                mm->context.asce_limit = STACK_TOP_MAX;
  44                mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  45                                   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
  46                break;
  47        case -PAGE_SIZE:
  48                /* forked 5-level task, set new asce with new_mm->pgd */
  49                mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  50                        _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
  51                break;
  52        case 1UL << 53:
  53                /* forked 4-level task, set new asce with new mm->pgd */
  54                mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  55                                   _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
  56                break;
  57        case 1UL << 31:
  58                /* forked 2-level compat task, set new asce with new mm->pgd */
  59                mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  60                                   _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
  61                /* pgd_alloc() did not increase mm->nr_pmds */
  62                mm_inc_nr_pmds(mm);
  63        }
  64        crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  65        return 0;
  66}
  67
  68#define destroy_context(mm)             do { } while (0)
  69
  70static inline void set_user_asce(struct mm_struct *mm)
  71{
  72        S390_lowcore.user_asce = mm->context.asce;
  73        if (current->thread.mm_segment.ar4)
  74                __ctl_load(S390_lowcore.user_asce, 7, 7);
  75        set_cpu_flag(CIF_ASCE_PRIMARY);
  76}
  77
  78static inline void clear_user_asce(void)
  79{
  80        S390_lowcore.user_asce = S390_lowcore.kernel_asce;
  81
  82        __ctl_load(S390_lowcore.user_asce, 1, 1);
  83        __ctl_load(S390_lowcore.user_asce, 7, 7);
  84}
  85
  86static inline void load_kernel_asce(void)
  87{
  88        unsigned long asce;
  89
  90        __ctl_store(asce, 1, 1);
  91        if (asce != S390_lowcore.kernel_asce)
  92                __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  93        set_cpu_flag(CIF_ASCE_PRIMARY);
  94}
  95
  96static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  97                             struct task_struct *tsk)
  98{
  99        int cpu = smp_processor_id();
 100
 101        S390_lowcore.user_asce = next->context.asce;
 102        if (prev == next)
 103                return;
 104        cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
 105        cpumask_set_cpu(cpu, mm_cpumask(next));
 106        /* Clear old ASCE by loading the kernel ASCE. */
 107        __ctl_load(S390_lowcore.kernel_asce, 1, 1);
 108        __ctl_load(S390_lowcore.kernel_asce, 7, 7);
 109        cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
 110}
 111
 112#define finish_arch_post_lock_switch finish_arch_post_lock_switch
 113static inline void finish_arch_post_lock_switch(void)
 114{
 115        struct task_struct *tsk = current;
 116        struct mm_struct *mm = tsk->mm;
 117
 118        load_kernel_asce();
 119        if (mm) {
 120                preempt_disable();
 121                while (atomic_read(&mm->context.flush_count))
 122                        cpu_relax();
 123
 124                if (mm->context.flush_mm)
 125                        __tlb_flush_mm(mm);
 126                preempt_enable();
 127        }
 128        set_fs(current->thread.mm_segment);
 129}
 130
 131#define enter_lazy_tlb(mm,tsk)  do { } while (0)
 132#define deactivate_mm(tsk,mm)   do { } while (0)
 133
 134static inline void activate_mm(struct mm_struct *prev,
 135                               struct mm_struct *next)
 136{
 137        switch_mm(prev, next, current);
 138        set_user_asce(next);
 139}
 140
 141static inline void arch_dup_mmap(struct mm_struct *oldmm,
 142                                 struct mm_struct *mm)
 143{
 144}
 145
 146static inline void arch_exit_mmap(struct mm_struct *mm)
 147{
 148}
 149
 150static inline void arch_unmap(struct mm_struct *mm,
 151                        struct vm_area_struct *vma,
 152                        unsigned long start, unsigned long end)
 153{
 154}
 155
 156static inline void arch_bprm_mm_init(struct mm_struct *mm,
 157                                     struct vm_area_struct *vma)
 158{
 159}
 160
 161static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
 162                bool write, bool execute, bool foreign)
 163{
 164        /* by default, allow everything */
 165        return true;
 166}
 167#endif /* __S390_MMU_CONTEXT_H */
 168