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 #ifdef CONFIG_PGSTE 29 mm->context.alloc_pgste = page_table_allocate_pgste || 30 test_thread_flag(TIF_PGSTE) || 31 current->mm->context.alloc_pgste; 32 mm->context.has_pgste = 0; 33 mm->context.use_skey = 0; 34 mm->context.use_cmma = 0; 35 #endif 36 switch (mm->context.asce_limit) { 37 case _REGION2_SIZE: 38 /* 39 * forked 3-level task, fall through to set new asce with new 40 * mm->pgd 41 */ 42 case 0: 43 /* context created by exec, set asce limit to 4TB */ 44 mm->context.asce_limit = STACK_TOP_MAX; 45 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | 46 _ASCE_USER_BITS | _ASCE_TYPE_REGION3; 47 break; 48 case -PAGE_SIZE: 49 /* forked 5-level task, set new asce with new_mm->pgd */ 50 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | 51 _ASCE_USER_BITS | _ASCE_TYPE_REGION1; 52 break; 53 case _REGION1_SIZE: 54 /* forked 4-level task, set new asce with new mm->pgd */ 55 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | 56 _ASCE_USER_BITS | _ASCE_TYPE_REGION2; 57 break; 58 case _REGION3_SIZE: 59 /* forked 2-level compat task, set new asce with new mm->pgd */ 60 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | 61 _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT; 62 /* pgd_alloc() did not increase mm->nr_pmds */ 63 mm_inc_nr_pmds(mm); 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 if (current->thread.mm_segment.ar4) 75 __ctl_load(S390_lowcore.user_asce, 7, 7); 76 set_cpu_flag(CIF_ASCE_PRIMARY); 77 } 78 79 static inline void clear_user_asce(void) 80 { 81 S390_lowcore.user_asce = S390_lowcore.kernel_asce; 82 83 __ctl_load(S390_lowcore.user_asce, 1, 1); 84 __ctl_load(S390_lowcore.user_asce, 7, 7); 85 } 86 87 static inline void load_kernel_asce(void) 88 { 89 unsigned long asce; 90 91 __ctl_store(asce, 1, 1); 92 if (asce != S390_lowcore.kernel_asce) 93 __ctl_load(S390_lowcore.kernel_asce, 1, 1); 94 set_cpu_flag(CIF_ASCE_PRIMARY); 95 } 96 97 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, 98 struct task_struct *tsk) 99 { 100 int cpu = smp_processor_id(); 101 102 S390_lowcore.user_asce = next->context.asce; 103 if (prev == next) 104 return; 105 cpumask_set_cpu(cpu, &next->context.cpu_attach_mask); 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 113 static 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 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); 124 __tlb_flush_mm_lazy(mm); 125 preempt_enable(); 126 } 127 set_fs(current->thread.mm_segment); 128 } 129 130 #define enter_lazy_tlb(mm,tsk) do { } while (0) 131 #define deactivate_mm(tsk,mm) do { } while (0) 132 133 static inline void activate_mm(struct mm_struct *prev, 134 struct mm_struct *next) 135 { 136 switch_mm(prev, next, current); 137 cpumask_set_cpu(smp_processor_id(), mm_cpumask(next)); 138 set_user_asce(next); 139 } 140 141 #endif /* __S390_MMU_CONTEXT_H */ 142