include/asm/mmu_context.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  *  S390 version
0004  *
0005  *  Derived from "include/asm-i386/mmu_context.h"
0006  */
0007
0008 #ifndef __S390_MMU_CONTEXT_H
0009 #define __S390_MMU_CONTEXT_H
0010
0011 #include <asm/pgalloc.h>
0012 #include <linux/uaccess.h>
0013 #include <linux/mm_types.h>
0014 #include <asm/tlbflush.h>
0015 #include <asm/ctl_reg.h>
0016 #include <asm-generic/mm_hooks.h>
0017
0018 #define init_new_context init_new_context
0019 static inline int init_new_context(struct task_struct *tsk,
0020                    struct mm_struct *mm)
0021 {
0022     unsigned long asce_type, init_entry;
0023
0024     spin_lock_init(&mm->context.lock);
0025     INIT_LIST_HEAD(&mm->context.pgtable_list);
0026     INIT_LIST_HEAD(&mm->context.gmap_list);
0027     cpumask_clear(&mm->context.cpu_attach_mask);
0028     atomic_set(&mm->context.flush_count, 0);
0029     atomic_set(&mm->context.protected_count, 0);
0030     mm->context.gmap_asce = 0;
0031     mm->context.flush_mm = 0;
0032 #ifdef CONFIG_PGSTE
0033     mm->context.alloc_pgste = page_table_allocate_pgste ||
0034         test_thread_flag(TIF_PGSTE) ||
0035         (current->mm && current->mm->context.alloc_pgste);
0036     mm->context.has_pgste = 0;
0037     mm->context.uses_skeys = 0;
0038     mm->context.uses_cmm = 0;
0039     mm->context.allow_gmap_hpage_1m = 0;
0040 #endif
0041     switch (mm->context.asce_limit) {
0042     default:
0043         /*
0044          * context created by exec, the value of asce_limit can
0045          * only be zero in this case
0046          */
0047         VM_BUG_ON(mm->context.asce_limit);
0048         /* continue as 3-level task */
0049         mm->context.asce_limit = _REGION2_SIZE;
0050         fallthrough;
0051     case _REGION2_SIZE:
0052         /* forked 3-level task */
0053         init_entry = _REGION3_ENTRY_EMPTY;
0054         asce_type = _ASCE_TYPE_REGION3;
0055         break;
0056     case TASK_SIZE_MAX:
0057         /* forked 5-level task */
0058         init_entry = _REGION1_ENTRY_EMPTY;
0059         asce_type = _ASCE_TYPE_REGION1;
0060         break;
0061     case _REGION1_SIZE:
0062         /* forked 4-level task */
0063         init_entry = _REGION2_ENTRY_EMPTY;
0064         asce_type = _ASCE_TYPE_REGION2;
0065         break;
0066     }
0067     mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
0068                _ASCE_USER_BITS | asce_type;
0069     crst_table_init((unsigned long *) mm->pgd, init_entry);
0070     return 0;
0071 }
0072
0073 static inline void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
0074                       struct task_struct *tsk)
0075 {
0076     int cpu = smp_processor_id();
0077
0078     if (next == &init_mm)
0079         S390_lowcore.user_asce = s390_invalid_asce;
0080     else
0081         S390_lowcore.user_asce = next->context.asce;
0082     cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
0083     /* Clear previous user-ASCE from CR7 */
0084     __ctl_load(s390_invalid_asce, 7, 7);
0085     if (prev != next)
0086         cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
0087 }
0088 #define switch_mm_irqs_off switch_mm_irqs_off
0089
0090 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
0091                  struct task_struct *tsk)
0092 {
0093     unsigned long flags;
0094
0095     local_irq_save(flags);
0096     switch_mm_irqs_off(prev, next, tsk);
0097     local_irq_restore(flags);
0098 }
0099
0100 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
0101 static inline void finish_arch_post_lock_switch(void)
0102 {
0103     struct task_struct *tsk = current;
0104     struct mm_struct *mm = tsk->mm;
0105
0106     if (mm) {
0107         preempt_disable();
0108         while (atomic_read(&mm->context.flush_count))
0109             cpu_relax();
0110         cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
0111         __tlb_flush_mm_lazy(mm);
0112         preempt_enable();
0113     }
0114     __ctl_load(S390_lowcore.user_asce, 7, 7);
0115 }
0116
0117 #define activate_mm activate_mm
0118 static inline void activate_mm(struct mm_struct *prev,
0119                                struct mm_struct *next)
0120 {
0121     switch_mm(prev, next, current);
0122     cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
0123     __ctl_load(S390_lowcore.user_asce, 7, 7);
0124 }
0125
0126 #include <asm-generic/mmu_context.h>
0127
0128 #endif /* __S390_MMU_CONTEXT_H */