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1 /*
2  *  PowerPC version
3  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
4  *
5  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
6  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
7  *    Copyright (C) 1996 Paul Mackerras
8  *
9  *  Derived from "arch/i386/mm/init.c"
10  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
11  *
12  *  Dave Engebretsen <engebret@us.ibm.com>
13  *      Rework for PPC64 port.
14  *
15  *  This program is free software; you can redistribute it and/or
16  *  modify it under the terms of the GNU General Public License
17  *  as published by the Free Software Foundation; either version
18  *  2 of the License, or (at your option) any later version.
19  *
20  */
21 
22 #undef DEBUG
23 
24 #include <linux/signal.h>
25 #include <linux/sched.h>
26 #include <linux/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/string.h>
29 #include <linux/types.h>
30 #include <linux/mman.h>
31 #include <linux/mm.h>
32 #include <linux/swap.h>
33 #include <linux/stddef.h>
34 #include <linux/vmalloc.h>
35 #include <linux/init.h>
36 #include <linux/delay.h>
37 #include <linux/bootmem.h>
38 #include <linux/highmem.h>
39 #include <linux/idr.h>
40 #include <linux/nodemask.h>
41 #include <linux/module.h>
42 #include <linux/poison.h>
43 #include <linux/memblock.h>
44 #include <linux/hugetlb.h>
45 #include <linux/slab.h>
46 
47 #include <asm/pgalloc.h>
48 #include <asm/page.h>
49 #include <asm/prom.h>
50 #include <asm/rtas.h>
51 #include <asm/io.h>
52 #include <asm/mmu_context.h>
53 #include <asm/pgtable.h>
54 #include <asm/mmu.h>
55 #include <asm/uaccess.h>
56 #include <asm/smp.h>
57 #include <asm/machdep.h>
58 #include <asm/tlb.h>
59 #include <asm/eeh.h>
60 #include <asm/processor.h>
61 #include <asm/mmzone.h>
62 #include <asm/cputable.h>
63 #include <asm/sections.h>
64 #include <asm/iommu.h>
65 #include <asm/abs_addr.h>
66 #include <asm/vdso.h>
67 
68 #include "mmu_decl.h"
69 
70 #ifdef CONFIG_PPC_STD_MMU_64
71 #if PGTABLE_RANGE > USER_VSID_RANGE
72 #warning Limited user VSID range means pagetable space is wasted
73 #endif
74 
75 #if (TASK_SIZE_USER64 < PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
76 #warning TASK_SIZE is smaller than it needs to be.
77 #endif
78 #endif /* CONFIG_PPC_STD_MMU_64 */
79 
80 phys_addr_t memstart_addr = ~0;
81 EXPORT_SYMBOL_GPL(memstart_addr);
82 phys_addr_t kernstart_addr;
83 EXPORT_SYMBOL_GPL(kernstart_addr);
84 
pgd_ctor(void * addr)85 static void pgd_ctor(void *addr)
86 {
87 	memset(addr, 0, PGD_TABLE_SIZE);
88 }
89 
pmd_ctor(void * addr)90 static void pmd_ctor(void *addr)
91 {
92 	memset(addr, 0, PMD_TABLE_SIZE);
93 }
94 
95 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
96 
97 /*
98  * Create a kmem_cache() for pagetables.  This is not used for PTE
99  * pages - they're linked to struct page, come from the normal free
100  * pages pool and have a different entry size (see real_pte_t) to
101  * everything else.  Caches created by this function are used for all
102  * the higher level pagetables, and for hugepage pagetables.
103  */
pgtable_cache_add(unsigned shift,void (* ctor)(void *))104 void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
105 {
106 	char *name;
107 	unsigned long table_size = sizeof(void *) << shift;
108 	unsigned long align = table_size;
109 
110 	/* When batching pgtable pointers for RCU freeing, we store
111 	 * the index size in the low bits.  Table alignment must be
112 	 * big enough to fit it.
113 	 *
114 	 * Likewise, hugeapge pagetable pointers contain a (different)
115 	 * shift value in the low bits.  All tables must be aligned so
116 	 * as to leave enough 0 bits in the address to contain it. */
117 	unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
118 				     HUGEPD_SHIFT_MASK + 1);
119 	struct kmem_cache *new;
120 
121 	/* It would be nice if this was a BUILD_BUG_ON(), but at the
122 	 * moment, gcc doesn't seem to recognize is_power_of_2 as a
123 	 * constant expression, so so much for that. */
124 	BUG_ON(!is_power_of_2(minalign));
125 	BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));
126 
127 	if (PGT_CACHE(shift))
128 		return; /* Already have a cache of this size */
129 
130 	align = max_t(unsigned long, align, minalign);
131 	name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
132 	new = kmem_cache_create(name, table_size, align, 0, ctor);
133 	PGT_CACHE(shift) = new;
134 
135 	pr_debug("Allocated pgtable cache for order %d\n", shift);
136 }
137 
138 
pgtable_cache_init(void)139 void pgtable_cache_init(void)
140 {
141 	pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
142 	pgtable_cache_add(PMD_INDEX_SIZE, pmd_ctor);
143 	if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_INDEX_SIZE))
144 		panic("Couldn't allocate pgtable caches");
145 
146 	/* In all current configs, when the PUD index exists it's the
147 	 * same size as either the pgd or pmd index.  Verify that the
148 	 * initialization above has also created a PUD cache.  This
149 	 * will need re-examiniation if we add new possibilities for
150 	 * the pagetable layout. */
151 	BUG_ON(PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE));
152 }
153 
154 #ifdef CONFIG_SPARSEMEM_VMEMMAP
155 /*
156  * Given an address within the vmemmap, determine the pfn of the page that
157  * represents the start of the section it is within.  Note that we have to
158  * do this by hand as the proffered address may not be correctly aligned.
159  * Subtraction of non-aligned pointers produces undefined results.
160  */
vmemmap_section_start(unsigned long page)161 static unsigned long __meminit vmemmap_section_start(unsigned long page)
162 {
163 	unsigned long offset = page - ((unsigned long)(vmemmap));
164 
165 	/* Return the pfn of the start of the section. */
166 	return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
167 }
168 
169 /*
170  * Check if this vmemmap page is already initialised.  If any section
171  * which overlaps this vmemmap page is initialised then this page is
172  * initialised already.
173  */
vmemmap_populated(unsigned long start,int page_size)174 static int __meminit vmemmap_populated(unsigned long start, int page_size)
175 {
176 	unsigned long end = start + page_size;
177 
178 	for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
179 		if (pfn_valid(vmemmap_section_start(start)))
180 			return 1;
181 
182 	return 0;
183 }
184 
185 /* On hash-based CPUs, the vmemmap is bolted in the hash table.
186  *
187  * On Book3E CPUs, the vmemmap is currently mapped in the top half of
188  * the vmalloc space using normal page tables, though the size of
189  * pages encoded in the PTEs can be different
190  */
191 
192 #ifdef CONFIG_PPC_BOOK3E
vmemmap_create_mapping(unsigned long start,unsigned long page_size,unsigned long phys)193 static void __meminit vmemmap_create_mapping(unsigned long start,
194 					     unsigned long page_size,
195 					     unsigned long phys)
196 {
197 	/* Create a PTE encoding without page size */
198 	unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
199 		_PAGE_KERNEL_RW;
200 
201 	/* PTEs only contain page size encodings up to 32M */
202 	BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
203 
204 	/* Encode the size in the PTE */
205 	flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
206 
207 	/* For each PTE for that area, map things. Note that we don't
208 	 * increment phys because all PTEs are of the large size and
209 	 * thus must have the low bits clear
210 	 */
211 	for (i = 0; i < page_size; i += PAGE_SIZE)
212 		BUG_ON(map_kernel_page(start + i, phys, flags));
213 }
214 #else /* CONFIG_PPC_BOOK3E */
vmemmap_create_mapping(unsigned long start,unsigned long page_size,unsigned long phys)215 static void __meminit vmemmap_create_mapping(unsigned long start,
216 					     unsigned long page_size,
217 					     unsigned long phys)
218 {
219 	int  mapped = htab_bolt_mapping(start, start + page_size, phys,
220 					PAGE_KERNEL, mmu_vmemmap_psize,
221 					mmu_kernel_ssize);
222 	BUG_ON(mapped < 0);
223 }
224 #endif /* CONFIG_PPC_BOOK3E */
225 
226 struct vmemmap_backing *vmemmap_list;
227 
vmemmap_list_alloc(int node)228 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
229 {
230 	static struct vmemmap_backing *next;
231 	static int num_left;
232 
233 	/* allocate a page when required and hand out chunks */
234 	if (!next || !num_left) {
235 		next = vmemmap_alloc_block(PAGE_SIZE, node);
236 		if (unlikely(!next)) {
237 			WARN_ON(1);
238 			return NULL;
239 		}
240 		num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
241 	}
242 
243 	num_left--;
244 
245 	return next++;
246 }
247 
vmemmap_list_populate(unsigned long phys,unsigned long start,int node)248 static __meminit void vmemmap_list_populate(unsigned long phys,
249 					    unsigned long start,
250 					    int node)
251 {
252 	struct vmemmap_backing *vmem_back;
253 
254 	vmem_back = vmemmap_list_alloc(node);
255 	if (unlikely(!vmem_back)) {
256 		WARN_ON(1);
257 		return;
258 	}
259 
260 	vmem_back->phys = phys;
261 	vmem_back->virt_addr = start;
262 	vmem_back->list = vmemmap_list;
263 
264 	vmemmap_list = vmem_back;
265 }
266 
vmemmap_populate(struct page * start_page,unsigned long nr_pages,int node)267 int __meminit vmemmap_populate(struct page *start_page,
268 			       unsigned long nr_pages, int node)
269 {
270 	unsigned long start = (unsigned long)start_page;
271 	unsigned long end = (unsigned long)(start_page + nr_pages);
272 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
273 
274 	/* Align to the page size of the linear mapping. */
275 	start = _ALIGN_DOWN(start, page_size);
276 
277 	pr_debug("vmemmap_populate page %p, %ld pages, node %d\n",
278 		 start_page, nr_pages, node);
279 	pr_debug(" -> map %lx..%lx\n", start, end);
280 
281 	for (; start < end; start += page_size) {
282 		void *p;
283 
284 		if (vmemmap_populated(start, page_size))
285 			continue;
286 
287 		p = vmemmap_alloc_block(page_size, node);
288 		if (!p)
289 			return -ENOMEM;
290 
291 		vmemmap_list_populate(__pa(p), start, node);
292 
293 		pr_debug("      * %016lx..%016lx allocated at %p\n",
294 			 start, start + page_size, p);
295 
296 		vmemmap_create_mapping(start, page_size, __pa(p));
297 	}
298 
299 	return 0;
300 }
301 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
302 
303