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 static inline int init_new_context(struct task_struct *tsk,
  19                                    struct mm_struct *mm)
  20 {
  21         unsigned long asce_type, init_entry;
  22
  23         spin_lock_init(&mm->context.lock);
  24         INIT_LIST_HEAD(&mm->context.pgtable_list);
  25         INIT_LIST_HEAD(&mm->context.gmap_list);
  26         cpumask_clear(&mm->context.cpu_attach_mask);
  27         atomic_set(&mm->context.flush_count, 0);
  28         atomic_set(&mm->context.is_protected, 0);
  29         mm->context.gmap_asce = 0;
  30         mm->context.flush_mm = 0;
  31 #ifdef CONFIG_PGSTE
  32         mm->context.alloc_pgste = page_table_allocate_pgste ||
  33                 test_thread_flag(TIF_PGSTE) ||
  34                 (current->mm && current->mm->context.alloc_pgste);
  35         mm->context.has_pgste = 0;
  36         mm->context.uses_skeys = 0;
  37         mm->context.uses_cmm = 0;
  38         mm->context.allow_gmap_hpage_1m = 0;
  39 #endif
  40         switch (mm->context.asce_limit) {
  41         default:
  42                 /*
  43                  * context created by exec, the value of asce_limit can
  44                  * only be zero in this case
  45                  */
  46                 VM_BUG_ON(mm->context.asce_limit);
  47                 /* continue as 3-level task */
  48                 mm->context.asce_limit = _REGION2_SIZE;
  49                 fallthrough;
  50         case _REGION2_SIZE:
  51                 /* forked 3-level task */
  52                 init_entry = _REGION3_ENTRY_EMPTY;
  53                 asce_type = _ASCE_TYPE_REGION3;
  54                 break;
  55         case TASK_SIZE_MAX:
  56                 /* forked 5-level task */
  57                 init_entry = _REGION1_ENTRY_EMPTY;
  58                 asce_type = _ASCE_TYPE_REGION1;
  59                 break;
  60         case _REGION1_SIZE:
  61                 /* forked 4-level task */
  62                 init_entry = _REGION2_ENTRY_EMPTY;
  63                 asce_type = _ASCE_TYPE_REGION2;
  64                 break;
  65         }
  66         mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  67                            _ASCE_USER_BITS | asce_type;
  68         crst_table_init((unsigned long *) mm->pgd, init_entry);
  69         return 0;
  70 }
  71
  72 #define destroy_context(mm)             do { } while (0)
  73
  74 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  75                              struct task_struct *tsk)
  76 {
  77         int cpu = smp_processor_id();
  78
  79         S390_lowcore.user_asce = next->context.asce;
  80         cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
  81         /* Clear previous user-ASCE from CR7 */
  82         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
  83         if (prev != next)
  84                 cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
  85 }
  86
  87 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
  88 static inline void finish_arch_post_lock_switch(void)
  89 {
  90         struct task_struct *tsk = current;
  91         struct mm_struct *mm = tsk->mm;
  92
  93         if (mm) {
  94                 preempt_disable();
  95                 while (atomic_read(&mm->context.flush_count))
  96                         cpu_relax();
  97                 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
  98                 __tlb_flush_mm_lazy(mm);
  99                 preempt_enable();
 100         }
 101         __ctl_load(S390_lowcore.user_asce, 7, 7);
 102 }
 103
 104 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
 105 #define deactivate_mm(tsk,mm)   do { } while (0)
 106
 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 #endif /* __S390_MMU_CONTEXT_H */