1 #include <linux/gfp.h> 2 #include <linux/initrd.h> 3 #include <linux/ioport.h> 4 #include <linux/swap.h> 5 #include <linux/memblock.h> 6 7 #include <asm/cacheflush.h> 8 #include <asm/e820.h> 9 #include <asm/init.h> 10 #include <asm/page.h> 11 #include <asm/page_types.h> 12 #include <asm/sections.h> 13 #include <asm/setup.h> 14 #include <asm/system.h> 15 #include <asm/tlbflush.h> 16 #include <asm/tlb.h> 17 #include <asm/proto.h> 18 19 unsigned long __initdata pgt_buf_start; 20 unsigned long __meminitdata pgt_buf_end; 21 unsigned long __meminitdata pgt_buf_top; 22 23 int after_bootmem; 24 25 int direct_gbpages 26 #ifdef CONFIG_DIRECT_GBPAGES 27 = 1 28 #endif 29 ; 30 31 static void __init find_early_table_space(unsigned long end, int use_pse, 32 int use_gbpages) 33 { 34 unsigned long puds, pmds, ptes, tables, start = 0, good_end = end; 35 phys_addr_t base; 36 37 puds = (end + PUD_SIZE - 1) >> PUD_SHIFT; 38 tables = roundup(puds * sizeof(pud_t), PAGE_SIZE); 39 40 if (use_gbpages) { 41 unsigned long extra; 42 43 extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT); 44 pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT; 45 } else 46 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT; 47 48 tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE); 49 50 if (use_pse) { 51 unsigned long extra; 52 53 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT); 54 #ifdef CONFIG_X86_32 55 extra += PMD_SIZE; 56 #endif 57 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT; 58 } else 59 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT; 60 61 tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE); 62 63 #ifdef CONFIG_X86_32 64 /* for fixmap */ 65 tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE); 66 #endif 67 good_end = max_pfn_mapped << PAGE_SHIFT; 68 69 base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE); 70 if (base == MEMBLOCK_ERROR) 71 panic("Cannot find space for the kernel page tables"); 72 73 pgt_buf_start = base >> PAGE_SHIFT; 74 pgt_buf_end = pgt_buf_start; 75 pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT); 76 77 printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n", 78 end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT); 79 } 80 81 void __init native_pagetable_reserve(u64 start, u64 end) 82 { 83 memblock_x86_reserve_range(start, end, "PGTABLE"); 84 } 85 86 struct map_range { 87 unsigned long start; 88 unsigned long end; 89 unsigned page_size_mask; 90 }; 91 92 #ifdef CONFIG_X86_32 93 #define NR_RANGE_MR 3 94 #else /* CONFIG_X86_64 */ 95 #define NR_RANGE_MR 5 96 #endif 97 98 static int __meminit save_mr(struct map_range *mr, int nr_range, 99 unsigned long start_pfn, unsigned long end_pfn, 100 unsigned long page_size_mask) 101 { 102 if (start_pfn < end_pfn) { 103 if (nr_range >= NR_RANGE_MR) 104 panic("run out of range for init_memory_mapping\n"); 105 mr[nr_range].start = start_pfn<<PAGE_SHIFT; 106 mr[nr_range].end = end_pfn<<PAGE_SHIFT; 107 mr[nr_range].page_size_mask = page_size_mask; 108 nr_range++; 109 } 110 111 return nr_range; 112 } 113 114 /* 115 * Setup the direct mapping of the physical memory at PAGE_OFFSET. 116 * This runs before bootmem is initialized and gets pages directly from 117 * the physical memory. To access them they are temporarily mapped. 118 */ 119 unsigned long __init_refok init_memory_mapping(unsigned long start, 120 unsigned long end) 121 { 122 unsigned long page_size_mask = 0; 123 unsigned long start_pfn, end_pfn; 124 unsigned long ret = 0; 125 unsigned long pos; 126 127 struct map_range mr[NR_RANGE_MR]; 128 int nr_range, i; 129 int use_pse, use_gbpages; 130 131 printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end); 132 133 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK) 134 /* 135 * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages. 136 * This will simplify cpa(), which otherwise needs to support splitting 137 * large pages into small in interrupt context, etc. 138 */ 139 use_pse = use_gbpages = 0; 140 #else 141 use_pse = cpu_has_pse; 142 use_gbpages = direct_gbpages; 143 #endif 144 145 /* Enable PSE if available */ 146 if (cpu_has_pse) 147 set_in_cr4(X86_CR4_PSE); 148 149 /* Enable PGE if available */ 150 if (cpu_has_pge) { 151 set_in_cr4(X86_CR4_PGE); 152 __supported_pte_mask |= _PAGE_GLOBAL; 153 } 154 155 if (use_gbpages) 156 page_size_mask |= 1 << PG_LEVEL_1G; 157 if (use_pse) 158 page_size_mask |= 1 << PG_LEVEL_2M; 159 160 memset(mr, 0, sizeof(mr)); 161 nr_range = 0; 162 163 /* head if not big page alignment ? */ 164 start_pfn = start >> PAGE_SHIFT; 165 pos = start_pfn << PAGE_SHIFT; 166 #ifdef CONFIG_X86_32 167 /* 168 * Don't use a large page for the first 2/4MB of memory 169 * because there are often fixed size MTRRs in there 170 * and overlapping MTRRs into large pages can cause 171 * slowdowns. 172 */ 173 if (pos == 0) 174 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT); 175 else 176 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT) 177 << (PMD_SHIFT - PAGE_SHIFT); 178 #else /* CONFIG_X86_64 */ 179 end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT) 180 << (PMD_SHIFT - PAGE_SHIFT); 181 #endif 182 if (end_pfn > (end >> PAGE_SHIFT)) 183 end_pfn = end >> PAGE_SHIFT; 184 if (start_pfn < end_pfn) { 185 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0); 186 pos = end_pfn << PAGE_SHIFT; 187 } 188 189 /* big page (2M) range */ 190 start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT) 191 << (PMD_SHIFT - PAGE_SHIFT); 192 #ifdef CONFIG_X86_32 193 end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT); 194 #else /* CONFIG_X86_64 */ 195 end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT) 196 << (PUD_SHIFT - PAGE_SHIFT); 197 if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT))) 198 end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)); 199 #endif 200 201 if (start_pfn < end_pfn) { 202 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 203 page_size_mask & (1<<PG_LEVEL_2M)); 204 pos = end_pfn << PAGE_SHIFT; 205 } 206 207 #ifdef CONFIG_X86_64 208 /* big page (1G) range */ 209 start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT) 210 << (PUD_SHIFT - PAGE_SHIFT); 211 end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT); 212 if (start_pfn < end_pfn) { 213 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 214 page_size_mask & 215 ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G))); 216 pos = end_pfn << PAGE_SHIFT; 217 } 218 219 /* tail is not big page (1G) alignment */ 220 start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT) 221 << (PMD_SHIFT - PAGE_SHIFT); 222 end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT); 223 if (start_pfn < end_pfn) { 224 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 225 page_size_mask & (1<<PG_LEVEL_2M)); 226 pos = end_pfn << PAGE_SHIFT; 227 } 228 #endif 229 230 /* tail is not big page (2M) alignment */ 231 start_pfn = pos>>PAGE_SHIFT; 232 end_pfn = end>>PAGE_SHIFT; 233 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0); 234 235 /* try to merge same page size and continuous */ 236 for (i = 0; nr_range > 1 && i < nr_range - 1; i++) { 237 unsigned long old_start; 238 if (mr[i].end != mr[i+1].start || 239 mr[i].page_size_mask != mr[i+1].page_size_mask) 240 continue; 241 /* move it */ 242 old_start = mr[i].start; 243 memmove(&mr[i], &mr[i+1], 244 (nr_range - 1 - i) * sizeof(struct map_range)); 245 mr[i--].start = old_start; 246 nr_range--; 247 } 248 249 for (i = 0; i < nr_range; i++) 250 printk(KERN_DEBUG " %010lx - %010lx page %s\n", 251 mr[i].start, mr[i].end, 252 (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":( 253 (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k")); 254 255 /* 256 * Find space for the kernel direct mapping tables. 257 * 258 * Later we should allocate these tables in the local node of the 259 * memory mapped. Unfortunately this is done currently before the 260 * nodes are discovered. 261 */ 262 if (!after_bootmem) 263 find_early_table_space(end, use_pse, use_gbpages); 264 265 for (i = 0; i < nr_range; i++) 266 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end, 267 mr[i].page_size_mask); 268 269 #ifdef CONFIG_X86_32 270 early_ioremap_page_table_range_init(); 271 272 load_cr3(swapper_pg_dir); 273 #endif 274 275 __flush_tlb_all(); 276 277 /* 278 * Reserve the kernel pagetable pages we used (pgt_buf_start - 279 * pgt_buf_end) and free the other ones (pgt_buf_end - pgt_buf_top) 280 * so that they can be reused for other purposes. 281 * 282 * On native it just means calling memblock_x86_reserve_range, on Xen it 283 * also means marking RW the pagetable pages that we allocated before 284 * but that haven't been used. 285 * 286 * In fact on xen we mark RO the whole range pgt_buf_start - 287 * pgt_buf_top, because we have to make sure that when 288 * init_memory_mapping reaches the pagetable pages area, it maps 289 * RO all the pagetable pages, including the ones that are beyond 290 * pgt_buf_end at that time. 291 */ 292 if (!after_bootmem && pgt_buf_end > pgt_buf_start) 293 x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start), 294 PFN_PHYS(pgt_buf_end)); 295 296 if (!after_bootmem) 297 early_memtest(start, end); 298 299 return ret >> PAGE_SHIFT; 300 } 301 302 303 /* 304 * devmem_is_allowed() checks to see if /dev/mem access to a certain address 305 * is valid. The argument is a physical page number. 306 * 307 * 308 * On x86, access has to be given to the first megabyte of ram because that area 309 * contains bios code and data regions used by X and dosemu and similar apps. 310 * Access has to be given to non-kernel-ram areas as well, these contain the PCI 311 * mmio resources as well as potential bios/acpi data regions. 312 */ 313 int devmem_is_allowed(unsigned long pagenr) 314 { 315 if (pagenr <= 256) 316 return 1; 317 if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) 318 return 0; 319 if (!page_is_ram(pagenr)) 320 return 1; 321 return 0; 322 } 323 324 void free_init_pages(char *what, unsigned long begin, unsigned long end) 325 { 326 unsigned long addr; 327 unsigned long begin_aligned, end_aligned; 328 329 /* Make sure boundaries are page aligned */ 330 begin_aligned = PAGE_ALIGN(begin); 331 end_aligned = end & PAGE_MASK; 332 333 if (WARN_ON(begin_aligned != begin || end_aligned != end)) { 334 begin = begin_aligned; 335 end = end_aligned; 336 } 337 338 if (begin >= end) 339 return; 340 341 addr = begin; 342 343 /* 344 * If debugging page accesses then do not free this memory but 345 * mark them not present - any buggy init-section access will 346 * create a kernel page fault: 347 */ 348 #ifdef CONFIG_DEBUG_PAGEALLOC 349 printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n", 350 begin, end); 351 set_memory_np(begin, (end - begin) >> PAGE_SHIFT); 352 #else 353 /* 354 * We just marked the kernel text read only above, now that 355 * we are going to free part of that, we need to make that 356 * writeable and non-executable first. 357 */ 358 set_memory_nx(begin, (end - begin) >> PAGE_SHIFT); 359 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT); 360 361 printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10); 362 363 for (; addr < end; addr += PAGE_SIZE) { 364 ClearPageReserved(virt_to_page(addr)); 365 init_page_count(virt_to_page(addr)); 366 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE); 367 free_page(addr); 368 totalram_pages++; 369 } 370 #endif 371 } 372 373 void free_initmem(void) 374 { 375 free_init_pages("unused kernel memory", 376 (unsigned long)(&__init_begin), 377 (unsigned long)(&__init_end)); 378 } 379 380 #ifdef CONFIG_BLK_DEV_INITRD 381 void free_initrd_mem(unsigned long start, unsigned long end) 382 { 383 /* 384 * end could be not aligned, and We can not align that, 385 * decompresser could be confused by aligned initrd_end 386 * We already reserve the end partial page before in 387 * - i386_start_kernel() 388 * - x86_64_start_kernel() 389 * - relocate_initrd() 390 * So here We can do PAGE_ALIGN() safely to get partial page to be freed 391 */ 392 free_init_pages("initrd memory", start, PAGE_ALIGN(end)); 393 } 394 #endif 395