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 #ifdef CONFIG_64BIT
23 	mm->context.asce_bits |= _ASCE_TYPE_REGION3;
24 #endif
25 	mm->context.has_pgste = 0;
26 	mm->context.use_skey = 0;
27 	mm->context.asce_limit = STACK_TOP_MAX;
28 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
29 	return 0;
30 }
31 
32 #define destroy_context(mm)             do { } while (0)
33 
34 static inline void set_user_asce(struct mm_struct *mm)
35 {
36 	S390_lowcore.user_asce = mm->context.asce_bits | __pa(mm->pgd);
37 	if (current->thread.mm_segment.ar4)
38 		__ctl_load(S390_lowcore.user_asce, 7, 7);
39 	set_cpu_flag(CIF_ASCE);
40 }
41 
42 static inline void clear_user_asce(void)
43 {
44 	S390_lowcore.user_asce = S390_lowcore.kernel_asce;
45 
46 	__ctl_load(S390_lowcore.user_asce, 1, 1);
47 	__ctl_load(S390_lowcore.user_asce, 7, 7);
48 }
49 
50 static inline void load_kernel_asce(void)
51 {
52 	unsigned long asce;
53 
54 	__ctl_store(asce, 1, 1);
55 	if (asce != S390_lowcore.kernel_asce)
56 		__ctl_load(S390_lowcore.kernel_asce, 1, 1);
57 	set_cpu_flag(CIF_ASCE);
58 }
59 
60 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
61 			     struct task_struct *tsk)
62 {
63 	int cpu = smp_processor_id();
64 
65 	if (prev == next)
66 		return;
67 	if (MACHINE_HAS_TLB_LC)
68 		cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
69 	/* Clear old ASCE by loading the kernel ASCE. */
70 	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
71 	__ctl_load(S390_lowcore.kernel_asce, 7, 7);
72 	atomic_inc(&next->context.attach_count);
73 	atomic_dec(&prev->context.attach_count);
74 	if (MACHINE_HAS_TLB_LC)
75 		cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
76 	S390_lowcore.user_asce = next->context.asce_bits | __pa(next->pgd);
77 }
78 
79 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
80 static inline void finish_arch_post_lock_switch(void)
81 {
82 	struct task_struct *tsk = current;
83 	struct mm_struct *mm = tsk->mm;
84 
85 	load_kernel_asce();
86 	if (mm) {
87 		preempt_disable();
88 		while (atomic_read(&mm->context.attach_count) >> 16)
89 			cpu_relax();
90 
91 		cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
92 		if (mm->context.flush_mm)
93 			__tlb_flush_mm(mm);
94 		preempt_enable();
95 	}
96 	set_fs(current->thread.mm_segment);
97 }
98 
99 #define enter_lazy_tlb(mm,tsk)	do { } while (0)
100 #define deactivate_mm(tsk,mm)	do { } while (0)
101 
102 static inline void activate_mm(struct mm_struct *prev,
103                                struct mm_struct *next)
104 {
105 	switch_mm(prev, next, current);
106 	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
107 	set_user_asce(next);
108 }
109 
110 static inline void arch_dup_mmap(struct mm_struct *oldmm,
111 				 struct mm_struct *mm)
112 {
113 #ifdef CONFIG_64BIT
114 	if (oldmm->context.asce_limit < mm->context.asce_limit)
115 		crst_table_downgrade(mm, oldmm->context.asce_limit);
116 #endif
117 }
118 
119 static inline void arch_exit_mmap(struct mm_struct *mm)
120 {
121 }
122 
123 static inline void arch_unmap(struct mm_struct *mm,
124 			struct vm_area_struct *vma,
125 			unsigned long start, unsigned long end)
126 {
127 }
128 
129 static inline void arch_bprm_mm_init(struct mm_struct *mm,
130 				     struct vm_area_struct *vma)
131 {
132 }
133 
134 #endif /* __S390_MMU_CONTEXT_H */
135