2 * MMU context allocation for 64-bit kernels.
4 * Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/string.h>
17 #include <linux/types.h>
19 #include <linux/spinlock.h>
20 #include <linux/idr.h>
21 #include <linux/export.h>
22 #include <linux/gfp.h>
23 #include <linux/slab.h>
25 #include <asm/mmu_context.h>
26 #include <asm/pgalloc.h>
30 static DEFINE_SPINLOCK(mmu_context_lock);
31 static DEFINE_IDA(mmu_context_ida);
33 static int __init_new_context(void)
39 if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
42 spin_lock(&mmu_context_lock);
43 err = ida_get_new_above(&mmu_context_ida, 1, &index);
44 spin_unlock(&mmu_context_lock);
51 if (index > MAX_USER_CONTEXT) {
52 spin_lock(&mmu_context_lock);
53 ida_remove(&mmu_context_ida, index);
54 spin_unlock(&mmu_context_lock);
61 int hash__alloc_context_id(void)
63 return __init_new_context();
65 EXPORT_SYMBOL_GPL(hash__alloc_context_id);
67 static int radix__init_new_context(struct mm_struct *mm, int index)
69 unsigned long rts_field;
72 * set the process table entry,
74 rts_field = radix__get_tree_size();
75 process_tb[index].prtb0 = cpu_to_be64(rts_field | __pa(mm->pgd) | RADIX_PGD_INDEX_SIZE);
79 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
83 index = __init_new_context();
87 if (radix_enabled()) {
88 radix__init_new_context(mm, index);
91 /* The old code would re-promote on fork, we don't do that
92 * when using slices as it could cause problem promoting slices
93 * that have been forced down to 4K
95 * For book3s we have MMU_NO_CONTEXT set to be ~0. Hence check
96 * explicitly against context.id == 0. This ensures that we
97 * properly initialize context slice details for newly allocated
98 * mm's (which will have id == 0) and don't alter context slice
99 * inherited via fork (which will have id != 0).
101 * We should not be calling init_new_context() on init_mm. Hence a
102 * check against 0 is ok.
104 if (mm->context.id == 0)
105 slice_set_user_psize(mm, mmu_virtual_psize);
106 subpage_prot_init_new_context(mm);
108 mm->context.id = index;
109 #ifdef CONFIG_PPC_ICSWX
110 mm->context.cop_lockp = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
111 if (!mm->context.cop_lockp) {
112 __destroy_context(index);
113 subpage_prot_free(mm);
114 mm->context.id = MMU_NO_CONTEXT;
117 spin_lock_init(mm->context.cop_lockp);
118 #endif /* CONFIG_PPC_ICSWX */
120 #ifdef CONFIG_PPC_64K_PAGES
121 mm->context.pte_frag = NULL;
123 #ifdef CONFIG_SPAPR_TCE_IOMMU
129 void __destroy_context(int context_id)
131 spin_lock(&mmu_context_lock);
132 ida_remove(&mmu_context_ida, context_id);
133 spin_unlock(&mmu_context_lock);
135 EXPORT_SYMBOL_GPL(__destroy_context);
137 #ifdef CONFIG_PPC_64K_PAGES
138 static void destroy_pagetable_page(struct mm_struct *mm)
144 pte_frag = mm->context.pte_frag;
148 page = virt_to_page(pte_frag);
149 /* drop all the pending references */
150 count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
151 /* We allow PTE_FRAG_NR fragments from a PTE page */
152 if (page_ref_sub_and_test(page, PTE_FRAG_NR - count)) {
153 pgtable_page_dtor(page);
154 free_hot_cold_page(page, 0);
159 static inline void destroy_pagetable_page(struct mm_struct *mm)
165 void destroy_context(struct mm_struct *mm)
167 #ifdef CONFIG_SPAPR_TCE_IOMMU
168 WARN_ON_ONCE(!list_empty(&mm->context.iommu_group_mem_list));
170 #ifdef CONFIG_PPC_ICSWX
171 drop_cop(mm->context.acop, mm);
172 kfree(mm->context.cop_lockp);
173 mm->context.cop_lockp = NULL;
174 #endif /* CONFIG_PPC_ICSWX */
177 process_tb[mm->context.id].prtb1 = 0;
179 subpage_prot_free(mm);
180 destroy_pagetable_page(mm);
181 __destroy_context(mm->context.id);
182 mm->context.id = MMU_NO_CONTEXT;
185 #ifdef CONFIG_PPC_RADIX_MMU
186 void radix__switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
188 asm volatile("isync": : :"memory");
189 mtspr(SPRN_PID, next->context.id);
190 asm volatile("isync \n"