arch/s390/include/asm/mmu_context.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  S390 version
   4  *
   5  *  Derived from "include/asm-i386/mmu_context.h"
   6  */
   7
   8 #ifndef __S390_MMU_CONTEXT_H
   9 #define __S390_MMU_CONTEXT_H
  10
  11 #include <asm/pgalloc.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/mm_types.h>
  14 #include <asm/tlbflush.h>
  15 #include <asm/ctl_reg.h>
  16 #include <asm-generic/mm_hooks.h>
  17
  18 #define init_new_context init_new_context
  19 static inline int init_new_context(struct task_struct *tsk,
  20                                    struct mm_struct *mm)
  21 {
  22         unsigned long asce_type, init_entry;
  23
  24         spin_lock_init(&mm->context.lock);
  25         INIT_LIST_HEAD(&mm->context.pgtable_list);
  26         INIT_LIST_HEAD(&mm->context.gmap_list);
  27         cpumask_clear(&mm->context.cpu_attach_mask);
  28         atomic_set(&mm->context.flush_count, 0);
  29         atomic_set(&mm->context.is_protected, 0);
  30         mm->context.gmap_asce = 0;
  31         mm->context.flush_mm = 0;
  32 #ifdef CONFIG_PGSTE
  33         mm->context.alloc_pgste = page_table_allocate_pgste ||
  34                 test_thread_flag(TIF_PGSTE) ||
  35                 (current->mm && current->mm->context.alloc_pgste);
  36         mm->context.has_pgste = 0;
  37         mm->context.uses_skeys = 0;
  38         mm->context.uses_cmm = 0;
  39         mm->context.allow_gmap_hpage_1m = 0;
  40 #endif
  41         switch (mm->context.asce_limit) {
  42         default:
  43                 /*
  44                  * context created by exec, the value of asce_limit can
  45                  * only be zero in this case
  46                  */
  47                 VM_BUG_ON(mm->context.asce_limit);
  48                 /* continue as 3-level task */
  49                 mm->context.asce_limit = _REGION2_SIZE;
  50                 fallthrough;
  51         case _REGION2_SIZE:
  52                 /* forked 3-level task */
  53                 init_entry = _REGION3_ENTRY_EMPTY;
  54                 asce_type = _ASCE_TYPE_REGION3;
  55                 break;
  56         case TASK_SIZE_MAX:
  57                 /* forked 5-level task */
  58                 init_entry = _REGION1_ENTRY_EMPTY;
  59                 asce_type = _ASCE_TYPE_REGION1;
  60                 break;
  61         case _REGION1_SIZE:
  62                 /* forked 4-level task */
  63                 init_entry = _REGION2_ENTRY_EMPTY;
  64                 asce_type = _ASCE_TYPE_REGION2;
  65                 break;
  66         }
  67         mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  68                            _ASCE_USER_BITS | asce_type;
  69         crst_table_init((unsigned long *) mm->pgd, init_entry);
  70         return 0;
  71 }
  72
  73 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  74                              struct task_struct *tsk)
  75 {
  76         int cpu = smp_processor_id();
  77
  78         if (next == &init_mm)
  79                 S390_lowcore.user_asce = s390_invalid_asce;
  80         else
  81                 S390_lowcore.user_asce = next->context.asce;
  82         cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
  83         /* Clear previous user-ASCE from CR7 */
  84         __ctl_load(s390_invalid_asce, 7, 7);
  85         if (prev != next)
  86                 cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
  87 }
  88
  89 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
  90 static inline void finish_arch_post_lock_switch(void)
  91 {
  92         struct task_struct *tsk = current;
  93         struct mm_struct *mm = tsk->mm;
  94
  95         if (mm) {
  96                 preempt_disable();
  97                 while (atomic_read(&mm->context.flush_count))
  98                         cpu_relax();
  99                 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
 100                 __tlb_flush_mm_lazy(mm);
 101                 preempt_enable();
 102         }
 103         __ctl_load(S390_lowcore.user_asce, 7, 7);
 104 }
 105
 106 #define activate_mm activate_mm
 107 static inline void activate_mm(struct mm_struct *prev,
 108                                struct mm_struct *next)
 109 {
 110         switch_mm(prev, next, current);
 111         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
 112         __ctl_load(S390_lowcore.user_asce, 7, 7);
 113 }
 114
 115 #include <asm-generic/mmu_context.h>
 116
 117 #endif /* __S390_MMU_CONTEXT_H */