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         spin_lock_init(&mm->context.lock);
  22         INIT_LIST_HEAD(&mm->context.pgtable_list);
  23         INIT_LIST_HEAD(&mm->context.gmap_list);
  24         cpumask_clear(&mm->context.cpu_attach_mask);
  25         atomic_set(&mm->context.flush_count, 0);
  26         mm->context.gmap_asce = 0;
  27         mm->context.flush_mm = 0;
  28         mm->context.compat_mm = test_thread_flag(TIF_31BIT);
  29 #ifdef CONFIG_PGSTE
  30         mm->context.alloc_pgste = page_table_allocate_pgste ||
  31                 test_thread_flag(TIF_PGSTE) ||
  32                 (current->mm && current->mm->context.alloc_pgste);
  33         mm->context.has_pgste = 0;
  34         mm->context.uses_skeys = 0;
  35         mm->context.uses_cmm = 0;
  36         mm->context.allow_gmap_hpage_1m = 0;
  37 #endif
  38         switch (mm->context.asce_limit) {
  39         case _REGION2_SIZE:
  40                 /*
  41                  * forked 3-level task, fall through to set new asce with new
  42                  * mm->pgd
  43                  */
  44         case 0:
  45                 /* context created by exec, set asce limit to 4TB */
  46                 mm->context.asce_limit = STACK_TOP_MAX;
  47                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  48                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
  49                 break;
  50         case -PAGE_SIZE:
  51                 /* forked 5-level task, set new asce with new_mm->pgd */
  52                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  53                         _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
  54                 break;
  55         case _REGION1_SIZE:
  56                 /* forked 4-level task, set new asce with new mm->pgd */
  57                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  58                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
  59                 break;
  60         case _REGION3_SIZE:
  61                 /* forked 2-level compat task, set new asce with new mm->pgd */
  62                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  63                                    _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
  64         }
  65         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  66         return 0;
  67 }
  68
  69 #define destroy_context(mm)             do { } while (0)
  70
  71 static inline void set_user_asce(struct mm_struct *mm)
  72 {
  73         S390_lowcore.user_asce = mm->context.asce;
  74         __ctl_load(S390_lowcore.user_asce, 1, 1);
  75         clear_cpu_flag(CIF_ASCE_PRIMARY);
  76 }
  77
  78 static inline void clear_user_asce(void)
  79 {
  80         S390_lowcore.user_asce = S390_lowcore.kernel_asce;
  81         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  82         set_cpu_flag(CIF_ASCE_PRIMARY);
  83 }
  84
  85 mm_segment_t enable_sacf_uaccess(void);
  86 void disable_sacf_uaccess(mm_segment_t old_fs);
  87
  88 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  89                              struct task_struct *tsk)
  90 {
  91         int cpu = smp_processor_id();
  92
  93         S390_lowcore.user_asce = next->context.asce;
  94         cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
  95         /* Clear previous user-ASCE from CR1 and CR7 */
  96         if (!test_cpu_flag(CIF_ASCE_PRIMARY)) {
  97                 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  98                 set_cpu_flag(CIF_ASCE_PRIMARY);
  99         }
 100         if (test_cpu_flag(CIF_ASCE_SECONDARY)) {
 101                 __ctl_load(S390_lowcore.vdso_asce, 7, 7);
 102                 clear_cpu_flag(CIF_ASCE_SECONDARY);
 103         }
 104         if (prev != next)
 105                 cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
 106 }
 107
 108 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
 109 static inline void finish_arch_post_lock_switch(void)
 110 {
 111         struct task_struct *tsk = current;
 112         struct mm_struct *mm = tsk->mm;
 113
 114         if (mm) {
 115                 preempt_disable();
 116                 while (atomic_read(&mm->context.flush_count))
 117                         cpu_relax();
 118                 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
 119                 __tlb_flush_mm_lazy(mm);
 120                 preempt_enable();
 121         }
 122         set_fs(current->thread.mm_segment);
 123 }
 124
 125 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
 126 #define deactivate_mm(tsk,mm)   do { } while (0)
 127
 128 static inline void activate_mm(struct mm_struct *prev,
 129                                struct mm_struct *next)
 130 {
 131         switch_mm(prev, next, current);
 132         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
 133         set_user_asce(next);
 134 }
 135
 136 #endif /* __S390_MMU_CONTEXT_H */