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 alloc_context_id(int min_id, int max_id)
38 if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
41 spin_lock(&mmu_context_lock);
42 err = ida_get_new_above(&mmu_context_ida, min_id, &index);
43 spin_unlock(&mmu_context_lock);
51 spin_lock(&mmu_context_lock);
52 ida_remove(&mmu_context_ida, index);
53 spin_unlock(&mmu_context_lock);
60 int hash__alloc_context_id(void)
62 return alloc_context_id(1, MAX_USER_CONTEXT);
64 EXPORT_SYMBOL_GPL(hash__alloc_context_id);
66 static int hash__init_new_context(struct mm_struct *mm)
70 index = hash__alloc_context_id();
75 * The old code would re-promote on fork, we don't do that when using
76 * slices as it could cause problem promoting slices that have been
79 * For book3s we have MMU_NO_CONTEXT set to be ~0. Hence check
80 * explicitly against context.id == 0. This ensures that we properly
81 * initialize context slice details for newly allocated mm's (which will
82 * have id == 0) and don't alter context slice inherited via fork (which
85 * We should not be calling init_new_context() on init_mm. Hence a
86 * check against 0 is OK.
88 if (mm->context.id == 0)
89 slice_set_user_psize(mm, mmu_virtual_psize);
91 subpage_prot_init_new_context(mm);
96 static int radix__init_new_context(struct mm_struct *mm)
98 unsigned long rts_field;
101 index = alloc_context_id(1, PRTB_ENTRIES - 1);
106 * set the process table entry,
108 rts_field = radix__get_tree_size();
109 process_tb[index].prtb0 = cpu_to_be64(rts_field | __pa(mm->pgd) | RADIX_PGD_INDEX_SIZE);
114 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
119 index = radix__init_new_context(mm);
121 index = hash__init_new_context(mm);
126 mm->context.id = index;
127 #ifdef CONFIG_PPC_ICSWX
128 mm->context.cop_lockp = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
129 if (!mm->context.cop_lockp) {
130 __destroy_context(index);
131 subpage_prot_free(mm);
132 mm->context.id = MMU_NO_CONTEXT;
135 spin_lock_init(mm->context.cop_lockp);
136 #endif /* CONFIG_PPC_ICSWX */
138 #ifdef CONFIG_PPC_64K_PAGES
139 mm->context.pte_frag = NULL;
141 #ifdef CONFIG_SPAPR_TCE_IOMMU
147 void __destroy_context(int context_id)
149 spin_lock(&mmu_context_lock);
150 ida_remove(&mmu_context_ida, context_id);
151 spin_unlock(&mmu_context_lock);
153 EXPORT_SYMBOL_GPL(__destroy_context);
155 #ifdef CONFIG_PPC_64K_PAGES
156 static void destroy_pagetable_page(struct mm_struct *mm)
162 pte_frag = mm->context.pte_frag;
166 page = virt_to_page(pte_frag);
167 /* drop all the pending references */
168 count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
169 /* We allow PTE_FRAG_NR fragments from a PTE page */
170 if (page_ref_sub_and_test(page, PTE_FRAG_NR - count)) {
171 pgtable_page_dtor(page);
172 free_hot_cold_page(page, 0);
177 static inline void destroy_pagetable_page(struct mm_struct *mm)
183 void destroy_context(struct mm_struct *mm)
185 #ifdef CONFIG_SPAPR_TCE_IOMMU
186 WARN_ON_ONCE(!list_empty(&mm->context.iommu_group_mem_list));
188 #ifdef CONFIG_PPC_ICSWX
189 drop_cop(mm->context.acop, mm);
190 kfree(mm->context.cop_lockp);
191 mm->context.cop_lockp = NULL;
192 #endif /* CONFIG_PPC_ICSWX */
195 process_tb[mm->context.id].prtb1 = 0;
197 subpage_prot_free(mm);
198 destroy_pagetable_page(mm);
199 __destroy_context(mm->context.id);
200 mm->context.id = MMU_NO_CONTEXT;
203 #ifdef CONFIG_PPC_RADIX_MMU
204 void radix__switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
206 asm volatile("isync": : :"memory");
207 mtspr(SPRN_PID, next->context.id);
208 asm volatile("isync \n"