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-rw-r--r--arch/powerpc/mm/tlb_64.c196
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diff --git a/arch/powerpc/mm/tlb_64.c b/arch/powerpc/mm/tlb_64.c
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1/*
2 * This file contains the routines for flushing entries from the
3 * TLB and MMU hash table.
4 *
5 * Derived from arch/ppc64/mm/init.c:
6 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
7 *
8 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
9 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
10 * Copyright (C) 1996 Paul Mackerras
11 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
12 *
13 * Derived from "arch/i386/mm/init.c"
14 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
15 *
16 * Dave Engebretsen <engebret@us.ibm.com>
17 * Rework for PPC64 port.
18 *
19 * This program is free software; you can redistribute it and/or
20 * modify it under the terms of the GNU General Public License
21 * as published by the Free Software Foundation; either version
22 * 2 of the License, or (at your option) any later version.
23 */
24#include <linux/config.h>
25#include <linux/kernel.h>
26#include <linux/mm.h>
27#include <linux/init.h>
28#include <linux/percpu.h>
29#include <linux/hardirq.h>
30#include <asm/pgalloc.h>
31#include <asm/tlbflush.h>
32#include <asm/tlb.h>
33#include <linux/highmem.h>
34
35DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);
36
37/* This is declared as we are using the more or less generic
38 * include/asm-ppc64/tlb.h file -- tgall
39 */
40DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
41DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur);
42unsigned long pte_freelist_forced_free;
43
44struct pte_freelist_batch
45{
46 struct rcu_head rcu;
47 unsigned int index;
48 pgtable_free_t tables[0];
49};
50
51DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur);
52unsigned long pte_freelist_forced_free;
53
54#define PTE_FREELIST_SIZE \
55 ((PAGE_SIZE - sizeof(struct pte_freelist_batch)) \
56 / sizeof(pgtable_free_t))
57
58#ifdef CONFIG_SMP
59static void pte_free_smp_sync(void *arg)
60{
61 /* Do nothing, just ensure we sync with all CPUs */
62}
63#endif
64
65/* This is only called when we are critically out of memory
66 * (and fail to get a page in pte_free_tlb).
67 */
68static void pgtable_free_now(pgtable_free_t pgf)
69{
70 pte_freelist_forced_free++;
71
72 smp_call_function(pte_free_smp_sync, NULL, 0, 1);
73
74 pgtable_free(pgf);
75}
76
77static void pte_free_rcu_callback(struct rcu_head *head)
78{
79 struct pte_freelist_batch *batch =
80 container_of(head, struct pte_freelist_batch, rcu);
81 unsigned int i;
82
83 for (i = 0; i < batch->index; i++)
84 pgtable_free(batch->tables[i]);
85
86 free_page((unsigned long)batch);
87}
88
89static void pte_free_submit(struct pte_freelist_batch *batch)
90{
91 INIT_RCU_HEAD(&batch->rcu);
92 call_rcu(&batch->rcu, pte_free_rcu_callback);
93}
94
95void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf)
96{
97 /* This is safe as we are holding page_table_lock */
98 cpumask_t local_cpumask = cpumask_of_cpu(smp_processor_id());
99 struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);
100
101 if (atomic_read(&tlb->mm->mm_users) < 2 ||
102 cpus_equal(tlb->mm->cpu_vm_mask, local_cpumask)) {
103 pgtable_free(pgf);
104 return;
105 }
106
107 if (*batchp == NULL) {
108 *batchp = (struct pte_freelist_batch *)__get_free_page(GFP_ATOMIC);
109 if (*batchp == NULL) {
110 pgtable_free_now(pgf);
111 return;
112 }
113 (*batchp)->index = 0;
114 }
115 (*batchp)->tables[(*batchp)->index++] = pgf;
116 if ((*batchp)->index == PTE_FREELIST_SIZE) {
117 pte_free_submit(*batchp);
118 *batchp = NULL;
119 }
120}
121
122/*
123 * Update the MMU hash table to correspond with a change to
124 * a Linux PTE. If wrprot is true, it is permissible to
125 * change the existing HPTE to read-only rather than removing it
126 * (if we remove it we should clear the _PTE_HPTEFLAGS bits).
127 */
128void hpte_update(struct mm_struct *mm, unsigned long addr,
129 unsigned long pte, int wrprot)
130{
131 struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
132 unsigned long vsid;
133 int i;
134
135 i = batch->index;
136
137 /*
138 * This can happen when we are in the middle of a TLB batch and
139 * we encounter memory pressure (eg copy_page_range when it tries
140 * to allocate a new pte). If we have to reclaim memory and end
141 * up scanning and resetting referenced bits then our batch context
142 * will change mid stream.
143 */
144 if (i != 0 && (mm != batch->mm || batch->large != pte_huge(pte))) {
145 flush_tlb_pending();
146 i = 0;
147 }
148 if (i == 0) {
149 batch->mm = mm;
150 batch->large = pte_huge(pte);
151 }
152 if (addr < KERNELBASE) {
153 vsid = get_vsid(mm->context.id, addr);
154 WARN_ON(vsid == 0);
155 } else
156 vsid = get_kernel_vsid(addr);
157 batch->vaddr[i] = (vsid << 28 ) | (addr & 0x0fffffff);
158 batch->pte[i] = __pte(pte);
159 batch->index = ++i;
160 if (i >= PPC64_TLB_BATCH_NR)
161 flush_tlb_pending();
162}
163
164void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
165{
166 int i;
167 int cpu;
168 cpumask_t tmp;
169 int local = 0;
170
171 BUG_ON(in_interrupt());
172
173 cpu = get_cpu();
174 i = batch->index;
175 tmp = cpumask_of_cpu(cpu);
176 if (cpus_equal(batch->mm->cpu_vm_mask, tmp))
177 local = 1;
178
179 if (i == 1)
180 flush_hash_page(batch->vaddr[0], batch->pte[0], local);
181 else
182 flush_hash_range(i, local);
183 batch->index = 0;
184 put_cpu();
185}
186
187void pte_free_finish(void)
188{
189 /* This is safe as we are holding page_table_lock */
190 struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);
191
192 if (*batchp == NULL)
193 return;
194 pte_free_submit(*batchp);
195 *batchp = NULL;
196}
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