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