1 /*
2  *  S390 version
3  *
4  *  Derived from "include/asm-i386/mmu_context.h"
5  */
6 
7 #ifndef __S390_MMU_CONTEXT_H
8 #define __S390_MMU_CONTEXT_H
9 
10 #include <asm/pgalloc.h>
11 #include <asm/uaccess.h>
12 #include <asm/tlbflush.h>
13 #include <asm/ctl_reg.h>
14 
15 static inline int init_new_context(struct task_struct *tsk,
16 				   struct mm_struct *mm)
17 {
18 	cpumask_clear(&mm->context.cpu_attach_mask);
19 	atomic_set(&mm->context.attach_count, 0);
20 	mm->context.flush_mm = 0;
21 	mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
22 	mm->context.asce_bits |= _ASCE_TYPE_REGION3;
23 #ifdef CONFIG_PGSTE
24 	mm->context.alloc_pgste = page_table_allocate_pgste;
25 	mm->context.has_pgste = 0;
26 	mm->context.use_skey = 0;
27 #endif
28 	mm->context.asce_limit = STACK_TOP_MAX;
29 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
30 	return 0;
31 }
32 
33 #define destroy_context(mm)             do { } while (0)
34 
35 static inline void set_user_asce(struct mm_struct *mm)
36 {
37 	S390_lowcore.user_asce = mm->context.asce_bits | __pa(mm->pgd);
38 	if (current->thread.mm_segment.ar4)
39 		__ctl_load(S390_lowcore.user_asce, 7, 7);
40 	set_cpu_flag(CIF_ASCE);
41 }
42 
43 static inline void clear_user_asce(void)
44 {
45 	S390_lowcore.user_asce = S390_lowcore.kernel_asce;
46 
47 	__ctl_load(S390_lowcore.user_asce, 1, 1);
48 	__ctl_load(S390_lowcore.user_asce, 7, 7);
49 }
50 
51 static inline void load_kernel_asce(void)
52 {
53 	unsigned long asce;
54 
55 	__ctl_store(asce, 1, 1);
56 	if (asce != S390_lowcore.kernel_asce)
57 		__ctl_load(S390_lowcore.kernel_asce, 1, 1);
58 	set_cpu_flag(CIF_ASCE);
59 }
60 
61 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
62 			     struct task_struct *tsk)
63 {
64 	int cpu = smp_processor_id();
65 
66 	S390_lowcore.user_asce = next->context.asce_bits | __pa(next->pgd);
67 	if (prev == next)
68 		return;
69 	if (MACHINE_HAS_TLB_LC)
70 		cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
71 	/* Clear old ASCE by loading the kernel ASCE. */
72 	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
73 	__ctl_load(S390_lowcore.kernel_asce, 7, 7);
74 	atomic_inc(&next->context.attach_count);
75 	atomic_dec(&prev->context.attach_count);
76 	if (MACHINE_HAS_TLB_LC)
77 		cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
78 }
79 
80 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
81 static inline void finish_arch_post_lock_switch(void)
82 {
83 	struct task_struct *tsk = current;
84 	struct mm_struct *mm = tsk->mm;
85 
86 	load_kernel_asce();
87 	if (mm) {
88 		preempt_disable();
89 		while (atomic_read(&mm->context.attach_count) >> 16)
90 			cpu_relax();
91 
92 		cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
93 		if (mm->context.flush_mm)
94 			__tlb_flush_mm(mm);
95 		preempt_enable();
96 	}
97 	set_fs(current->thread.mm_segment);
98 }
99 
100 #define enter_lazy_tlb(mm,tsk)	do { } while (0)
101 #define deactivate_mm(tsk,mm)	do { } while (0)
102 
103 static inline void activate_mm(struct mm_struct *prev,
104                                struct mm_struct *next)
105 {
106 	switch_mm(prev, next, current);
107 	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
108 	set_user_asce(next);
109 }
110 
111 static inline void arch_dup_mmap(struct mm_struct *oldmm,
112 				 struct mm_struct *mm)
113 {
114 	if (oldmm->context.asce_limit < mm->context.asce_limit)
115 		crst_table_downgrade(mm, oldmm->context.asce_limit);
116 }
117 
118 static inline void arch_exit_mmap(struct mm_struct *mm)
119 {
120 }
121 
122 static inline void arch_unmap(struct mm_struct *mm,
123 			struct vm_area_struct *vma,
124 			unsigned long start, unsigned long end)
125 {
126 }
127 
128 static inline void arch_bprm_mm_init(struct mm_struct *mm,
129 				     struct vm_area_struct *vma)
130 {
131 }
132 
133 #endif /* __S390_MMU_CONTEXT_H */
134