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/vdso.h> 66 67 #include "mmu_decl.h" 68 69 #ifdef CONFIG_PPC_STD_MMU_64 70 #if PGTABLE_RANGE > USER_VSID_RANGE 71 #warning Limited user VSID range means pagetable space is wasted 72 #endif 73 74 #if (TASK_SIZE_USER64 < PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE) 75 #warning TASK_SIZE is smaller than it needs to be. 76 #endif 77 #endif /* CONFIG_PPC_STD_MMU_64 */ 78 79 phys_addr_t memstart_addr = ~0; 80 EXPORT_SYMBOL_GPL(memstart_addr); 81 phys_addr_t kernstart_addr; 82 EXPORT_SYMBOL_GPL(kernstart_addr); 83 84 static void pgd_ctor(void *addr) 85 { 86 memset(addr, 0, PGD_TABLE_SIZE); 87 } 88 89 static void pmd_ctor(void *addr) 90 { 91 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 92 memset(addr, 0, PMD_TABLE_SIZE * 2); 93 #else 94 memset(addr, 0, PMD_TABLE_SIZE); 95 #endif 96 } 97 98 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE]; 99 100 /* 101 * Create a kmem_cache() for pagetables. This is not used for PTE 102 * pages - they're linked to struct page, come from the normal free 103 * pages pool and have a different entry size (see real_pte_t) to 104 * everything else. Caches created by this function are used for all 105 * the higher level pagetables, and for hugepage pagetables. 106 */ 107 void pgtable_cache_add(unsigned shift, void (*ctor)(void *)) 108 { 109 char *name; 110 unsigned long table_size = sizeof(void *) << shift; 111 unsigned long align = table_size; 112 113 /* When batching pgtable pointers for RCU freeing, we store 114 * the index size in the low bits. Table alignment must be 115 * big enough to fit it. 116 * 117 * Likewise, hugeapge pagetable pointers contain a (different) 118 * shift value in the low bits. All tables must be aligned so 119 * as to leave enough 0 bits in the address to contain it. */ 120 unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1, 121 HUGEPD_SHIFT_MASK + 1); 122 struct kmem_cache *new; 123 124 /* It would be nice if this was a BUILD_BUG_ON(), but at the 125 * moment, gcc doesn't seem to recognize is_power_of_2 as a 126 * constant expression, so so much for that. */ 127 BUG_ON(!is_power_of_2(minalign)); 128 BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE)); 129 130 if (PGT_CACHE(shift)) 131 return; /* Already have a cache of this size */ 132 133 align = max_t(unsigned long, align, minalign); 134 name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift); 135 new = kmem_cache_create(name, table_size, align, 0, ctor); 136 pgtable_cache[shift - 1] = new; 137 pr_debug("Allocated pgtable cache for order %d\n", shift); 138 } 139 140 141 void pgtable_cache_init(void) 142 { 143 pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor); 144 pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor); 145 if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_CACHE_INDEX)) 146 panic("Couldn't allocate pgtable caches"); 147 /* In all current configs, when the PUD index exists it's the 148 * same size as either the pgd or pmd index. Verify that the 149 * initialization above has also created a PUD cache. This 150 * will need re-examiniation if we add new possibilities for 151 * the pagetable layout. */ 152 BUG_ON(PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE)); 153 } 154 155 #ifdef CONFIG_SPARSEMEM_VMEMMAP 156 /* 157 * Given an address within the vmemmap, determine the pfn of the page that 158 * represents the start of the section it is within. Note that we have to 159 * do this by hand as the proffered address may not be correctly aligned. 160 * Subtraction of non-aligned pointers produces undefined results. 161 */ 162 static unsigned long __meminit vmemmap_section_start(unsigned long page) 163 { 164 unsigned long offset = page - ((unsigned long)(vmemmap)); 165 166 /* Return the pfn of the start of the section. */ 167 return (offset / sizeof(struct page)) & PAGE_SECTION_MASK; 168 } 169 170 /* 171 * Check if this vmemmap page is already initialised. If any section 172 * which overlaps this vmemmap page is initialised then this page is 173 * initialised already. 174 */ 175 static int __meminit vmemmap_populated(unsigned long start, int page_size) 176 { 177 unsigned long end = start + page_size; 178 179 for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page))) 180 if (pfn_valid(vmemmap_section_start(start))) 181 return 1; 182 183 return 0; 184 } 185 186 /* On hash-based CPUs, the vmemmap is bolted in the hash table. 187 * 188 * On Book3E CPUs, the vmemmap is currently mapped in the top half of 189 * the vmalloc space using normal page tables, though the size of 190 * pages encoded in the PTEs can be different 191 */ 192 193 #ifdef CONFIG_PPC_BOOK3E 194 static void __meminit vmemmap_create_mapping(unsigned long start, 195 unsigned long page_size, 196 unsigned long phys) 197 { 198 /* Create a PTE encoding without page size */ 199 unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED | 200 _PAGE_KERNEL_RW; 201 202 /* PTEs only contain page size encodings up to 32M */ 203 BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf); 204 205 /* Encode the size in the PTE */ 206 flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8; 207 208 /* For each PTE for that area, map things. Note that we don't 209 * increment phys because all PTEs are of the large size and 210 * thus must have the low bits clear 211 */ 212 for (i = 0; i < page_size; i += PAGE_SIZE) 213 BUG_ON(map_kernel_page(start + i, phys, flags)); 214 } 215 #else /* CONFIG_PPC_BOOK3E */ 216 static void __meminit vmemmap_create_mapping(unsigned long start, 217 unsigned long page_size, 218 unsigned long phys) 219 { 220 int mapped = htab_bolt_mapping(start, start + page_size, phys, 221 pgprot_val(PAGE_KERNEL), 222 mmu_vmemmap_psize, 223 mmu_kernel_ssize); 224 BUG_ON(mapped < 0); 225 } 226 #endif /* CONFIG_PPC_BOOK3E */ 227 228 struct vmemmap_backing *vmemmap_list; 229 230 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node) 231 { 232 static struct vmemmap_backing *next; 233 static int num_left; 234 235 /* allocate a page when required and hand out chunks */ 236 if (!next || !num_left) { 237 next = vmemmap_alloc_block(PAGE_SIZE, node); 238 if (unlikely(!next)) { 239 WARN_ON(1); 240 return NULL; 241 } 242 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing); 243 } 244 245 num_left--; 246 247 return next++; 248 } 249 250 static __meminit void vmemmap_list_populate(unsigned long phys, 251 unsigned long start, 252 int node) 253 { 254 struct vmemmap_backing *vmem_back; 255 256 vmem_back = vmemmap_list_alloc(node); 257 if (unlikely(!vmem_back)) { 258 WARN_ON(1); 259 return; 260 } 261 262 vmem_back->phys = phys; 263 vmem_back->virt_addr = start; 264 vmem_back->list = vmemmap_list; 265 266 vmemmap_list = vmem_back; 267 } 268 269 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) 270 { 271 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 272 273 /* Align to the page size of the linear mapping. */ 274 start = _ALIGN_DOWN(start, page_size); 275 276 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node); 277 278 for (; start < end; start += page_size) { 279 void *p; 280 281 if (vmemmap_populated(start, page_size)) 282 continue; 283 284 p = vmemmap_alloc_block(page_size, node); 285 if (!p) 286 return -ENOMEM; 287 288 vmemmap_list_populate(__pa(p), start, node); 289 290 pr_debug(" * %016lx..%016lx allocated at %p\n", 291 start, start + page_size, p); 292 293 vmemmap_create_mapping(start, page_size, __pa(p)); 294 } 295 296 return 0; 297 } 298 299 void vmemmap_free(unsigned long start, unsigned long end) 300 { 301 } 302 303 void register_page_bootmem_memmap(unsigned long section_nr, 304 struct page *start_page, unsigned long size) 305 { 306 } 307 308 /* 309 * We do not have access to the sparsemem vmemmap, so we fallback to 310 * walking the list of sparsemem blocks which we already maintain for 311 * the sake of crashdump. In the long run, we might want to maintain 312 * a tree if performance of that linear walk becomes a problem. 313 * 314 * realmode_pfn_to_page functions can fail due to: 315 * 1) As real sparsemem blocks do not lay in RAM continously (they 316 * are in virtual address space which is not available in the real mode), 317 * the requested page struct can be split between blocks so get_page/put_page 318 * may fail. 319 * 2) When huge pages are used, the get_page/put_page API will fail 320 * in real mode as the linked addresses in the page struct are virtual 321 * too. 322 */ 323 struct page *realmode_pfn_to_page(unsigned long pfn) 324 { 325 struct vmemmap_backing *vmem_back; 326 struct page *page; 327 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 328 unsigned long pg_va = (unsigned long) pfn_to_page(pfn); 329 330 for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) { 331 if (pg_va < vmem_back->virt_addr) 332 continue; 333 334 /* Check that page struct is not split between real pages */ 335 if ((pg_va + sizeof(struct page)) > 336 (vmem_back->virt_addr + page_size)) 337 return NULL; 338 339 page = (struct page *) (vmem_back->phys + pg_va - 340 vmem_back->virt_addr); 341 return page; 342 } 343 344 return NULL; 345 } 346 EXPORT_SYMBOL_GPL(realmode_pfn_to_page); 347 348 #elif defined(CONFIG_FLATMEM) 349 350 struct page *realmode_pfn_to_page(unsigned long pfn) 351 { 352 struct page *page = pfn_to_page(pfn); 353 return page; 354 } 355 EXPORT_SYMBOL_GPL(realmode_pfn_to_page); 356 357 #endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */ 358