1 /* 2 * This file contains the routines setting up the linux page tables. 3 * -- paulus 4 * 5 * Derived from arch/ppc/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 * 12 * Derived from "arch/i386/mm/init.c" 13 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 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 #include <linux/kernel.h> 23 #include <linux/module.h> 24 #include <linux/types.h> 25 #include <linux/mm.h> 26 #include <linux/vmalloc.h> 27 #include <linux/init.h> 28 #include <linux/highmem.h> 29 #include <linux/memblock.h> 30 #include <linux/slab.h> 31 32 #include <asm/pgtable.h> 33 #include <asm/pgalloc.h> 34 #include <asm/fixmap.h> 35 #include <asm/io.h> 36 #include <asm/setup.h> 37 38 #include "mmu_decl.h" 39 40 unsigned long ioremap_bot; 41 EXPORT_SYMBOL(ioremap_bot); /* aka VMALLOC_END */ 42 43 extern char etext[], _stext[], _sinittext[], _einittext[]; 44 45 #define PGDIR_ORDER (32 + PGD_T_LOG2 - PGDIR_SHIFT) 46 47 #ifndef CONFIG_PPC_4K_PAGES 48 static struct kmem_cache *pgtable_cache; 49 50 void pgtable_cache_init(void) 51 { 52 pgtable_cache = kmem_cache_create("PGDIR cache", 1 << PGDIR_ORDER, 53 1 << PGDIR_ORDER, 0, NULL); 54 if (pgtable_cache == NULL) 55 panic("Couldn't allocate pgtable caches"); 56 } 57 #endif 58 59 pgd_t *pgd_alloc(struct mm_struct *mm) 60 { 61 pgd_t *ret; 62 63 /* pgdir take page or two with 4K pages and a page fraction otherwise */ 64 #ifndef CONFIG_PPC_4K_PAGES 65 ret = kmem_cache_alloc(pgtable_cache, GFP_KERNEL | __GFP_ZERO); 66 #else 67 ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 68 PGDIR_ORDER - PAGE_SHIFT); 69 #endif 70 return ret; 71 } 72 73 void pgd_free(struct mm_struct *mm, pgd_t *pgd) 74 { 75 #ifndef CONFIG_PPC_4K_PAGES 76 kmem_cache_free(pgtable_cache, (void *)pgd); 77 #else 78 free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT); 79 #endif 80 } 81 82 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) 83 { 84 pte_t *pte; 85 86 if (slab_is_available()) { 87 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO); 88 } else { 89 pte = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE)); 90 if (pte) 91 clear_page(pte); 92 } 93 return pte; 94 } 95 96 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) 97 { 98 struct page *ptepage; 99 100 gfp_t flags = GFP_KERNEL | __GFP_ZERO; 101 102 ptepage = alloc_pages(flags, 0); 103 if (!ptepage) 104 return NULL; 105 if (!pgtable_page_ctor(ptepage)) { 106 __free_page(ptepage); 107 return NULL; 108 } 109 return ptepage; 110 } 111 112 void __iomem * 113 ioremap(phys_addr_t addr, unsigned long size) 114 { 115 return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED, 116 __builtin_return_address(0)); 117 } 118 EXPORT_SYMBOL(ioremap); 119 120 void __iomem * 121 ioremap_wc(phys_addr_t addr, unsigned long size) 122 { 123 return __ioremap_caller(addr, size, _PAGE_NO_CACHE, 124 __builtin_return_address(0)); 125 } 126 EXPORT_SYMBOL(ioremap_wc); 127 128 void __iomem * 129 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags) 130 { 131 /* writeable implies dirty for kernel addresses */ 132 if ((flags & (_PAGE_RW | _PAGE_RO)) != _PAGE_RO) 133 flags |= _PAGE_DIRTY | _PAGE_HWWRITE; 134 135 /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */ 136 flags &= ~(_PAGE_USER | _PAGE_EXEC); 137 138 #ifdef _PAGE_BAP_SR 139 /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format 140 * which means that we just cleared supervisor access... oops ;-) This 141 * restores it 142 */ 143 flags |= _PAGE_BAP_SR; 144 #endif 145 146 return __ioremap_caller(addr, size, flags, __builtin_return_address(0)); 147 } 148 EXPORT_SYMBOL(ioremap_prot); 149 150 void __iomem * 151 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags) 152 { 153 return __ioremap_caller(addr, size, flags, __builtin_return_address(0)); 154 } 155 156 void __iomem * 157 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags, 158 void *caller) 159 { 160 unsigned long v, i; 161 phys_addr_t p; 162 int err; 163 164 /* Make sure we have the base flags */ 165 if ((flags & _PAGE_PRESENT) == 0) 166 flags |= pgprot_val(PAGE_KERNEL); 167 168 /* Non-cacheable page cannot be coherent */ 169 if (flags & _PAGE_NO_CACHE) 170 flags &= ~_PAGE_COHERENT; 171 172 /* 173 * Choose an address to map it to. 174 * Once the vmalloc system is running, we use it. 175 * Before then, we use space going down from IOREMAP_TOP 176 * (ioremap_bot records where we're up to). 177 */ 178 p = addr & PAGE_MASK; 179 size = PAGE_ALIGN(addr + size) - p; 180 181 /* 182 * If the address lies within the first 16 MB, assume it's in ISA 183 * memory space 184 */ 185 if (p < 16*1024*1024) 186 p += _ISA_MEM_BASE; 187 188 #ifndef CONFIG_CRASH_DUMP 189 /* 190 * Don't allow anybody to remap normal RAM that we're using. 191 * mem_init() sets high_memory so only do the check after that. 192 */ 193 if (slab_is_available() && (p < virt_to_phys(high_memory)) && 194 !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) { 195 printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n", 196 (unsigned long long)p, __builtin_return_address(0)); 197 return NULL; 198 } 199 #endif 200 201 if (size == 0) 202 return NULL; 203 204 /* 205 * Is it already mapped? Perhaps overlapped by a previous 206 * mapping. 207 */ 208 v = p_block_mapped(p); 209 if (v) 210 goto out; 211 212 if (slab_is_available()) { 213 struct vm_struct *area; 214 area = get_vm_area_caller(size, VM_IOREMAP, caller); 215 if (area == 0) 216 return NULL; 217 area->phys_addr = p; 218 v = (unsigned long) area->addr; 219 } else { 220 v = (ioremap_bot -= size); 221 } 222 223 /* 224 * Should check if it is a candidate for a BAT mapping 225 */ 226 227 err = 0; 228 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 229 err = map_page(v+i, p+i, flags); 230 if (err) { 231 if (slab_is_available()) 232 vunmap((void *)v); 233 return NULL; 234 } 235 236 out: 237 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 238 } 239 EXPORT_SYMBOL(__ioremap); 240 241 void iounmap(volatile void __iomem *addr) 242 { 243 /* 244 * If mapped by BATs then there is nothing to do. 245 * Calling vfree() generates a benign warning. 246 */ 247 if (v_block_mapped((unsigned long)addr)) 248 return; 249 250 if (addr > high_memory && (unsigned long) addr < ioremap_bot) 251 vunmap((void *) (PAGE_MASK & (unsigned long)addr)); 252 } 253 EXPORT_SYMBOL(iounmap); 254 255 int map_page(unsigned long va, phys_addr_t pa, int flags) 256 { 257 pmd_t *pd; 258 pte_t *pg; 259 int err = -ENOMEM; 260 261 /* Use upper 10 bits of VA to index the first level map */ 262 pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va); 263 /* Use middle 10 bits of VA to index the second-level map */ 264 pg = pte_alloc_kernel(pd, va); 265 if (pg != 0) { 266 err = 0; 267 /* The PTE should never be already set nor present in the 268 * hash table 269 */ 270 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) && 271 flags); 272 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 273 __pgprot(flags))); 274 } 275 smp_wmb(); 276 return err; 277 } 278 279 /* 280 * Map in a chunk of physical memory starting at start. 281 */ 282 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top) 283 { 284 unsigned long v, s, f; 285 phys_addr_t p; 286 int ktext; 287 288 s = offset; 289 v = PAGE_OFFSET + s; 290 p = memstart_addr + s; 291 for (; s < top; s += PAGE_SIZE) { 292 ktext = ((char *)v >= _stext && (char *)v < etext) || 293 ((char *)v >= _sinittext && (char *)v < _einittext); 294 f = ktext ? pgprot_val(PAGE_KERNEL_TEXT) : pgprot_val(PAGE_KERNEL); 295 map_page(v, p, f); 296 #ifdef CONFIG_PPC_STD_MMU_32 297 if (ktext) 298 hash_preload(&init_mm, v, 0, 0x300); 299 #endif 300 v += PAGE_SIZE; 301 p += PAGE_SIZE; 302 } 303 } 304 305 void __init mapin_ram(void) 306 { 307 unsigned long s, top; 308 309 #ifndef CONFIG_WII 310 top = total_lowmem; 311 s = mmu_mapin_ram(top); 312 __mapin_ram_chunk(s, top); 313 #else 314 if (!wii_hole_size) { 315 s = mmu_mapin_ram(total_lowmem); 316 __mapin_ram_chunk(s, total_lowmem); 317 } else { 318 top = wii_hole_start; 319 s = mmu_mapin_ram(top); 320 __mapin_ram_chunk(s, top); 321 322 top = memblock_end_of_DRAM(); 323 s = wii_mmu_mapin_mem2(top); 324 __mapin_ram_chunk(s, top); 325 } 326 #endif 327 } 328 329 /* Scan the real Linux page tables and return a PTE pointer for 330 * a virtual address in a context. 331 * Returns true (1) if PTE was found, zero otherwise. The pointer to 332 * the PTE pointer is unmodified if PTE is not found. 333 */ 334 int 335 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) 336 { 337 pgd_t *pgd; 338 pud_t *pud; 339 pmd_t *pmd; 340 pte_t *pte; 341 int retval = 0; 342 343 pgd = pgd_offset(mm, addr & PAGE_MASK); 344 if (pgd) { 345 pud = pud_offset(pgd, addr & PAGE_MASK); 346 if (pud && pud_present(*pud)) { 347 pmd = pmd_offset(pud, addr & PAGE_MASK); 348 if (pmd_present(*pmd)) { 349 pte = pte_offset_map(pmd, addr & PAGE_MASK); 350 if (pte) { 351 retval = 1; 352 *ptep = pte; 353 if (pmdp) 354 *pmdp = pmd; 355 /* XXX caller needs to do pte_unmap, yuck */ 356 } 357 } 358 } 359 } 360 return(retval); 361 } 362 363 #ifdef CONFIG_DEBUG_PAGEALLOC 364 365 static int __change_page_attr(struct page *page, pgprot_t prot) 366 { 367 pte_t *kpte; 368 pmd_t *kpmd; 369 unsigned long address; 370 371 BUG_ON(PageHighMem(page)); 372 address = (unsigned long)page_address(page); 373 374 if (v_block_mapped(address)) 375 return 0; 376 if (!get_pteptr(&init_mm, address, &kpte, &kpmd)) 377 return -EINVAL; 378 __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0); 379 wmb(); 380 flush_tlb_page(NULL, address); 381 pte_unmap(kpte); 382 383 return 0; 384 } 385 386 /* 387 * Change the page attributes of an page in the linear mapping. 388 * 389 * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY 390 */ 391 static int change_page_attr(struct page *page, int numpages, pgprot_t prot) 392 { 393 int i, err = 0; 394 unsigned long flags; 395 396 local_irq_save(flags); 397 for (i = 0; i < numpages; i++, page++) { 398 err = __change_page_attr(page, prot); 399 if (err) 400 break; 401 } 402 local_irq_restore(flags); 403 return err; 404 } 405 406 407 void __kernel_map_pages(struct page *page, int numpages, int enable) 408 { 409 if (PageHighMem(page)) 410 return; 411 412 change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); 413 } 414 #endif /* CONFIG_DEBUG_PAGEALLOC */ 415 416 static int fixmaps; 417 418 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) 419 { 420 unsigned long address = __fix_to_virt(idx); 421 422 if (idx >= __end_of_fixed_addresses) { 423 BUG(); 424 return; 425 } 426 427 map_page(address, phys, pgprot_val(flags)); 428 fixmaps++; 429 } 430 431 void __this_fixmap_does_not_exist(void) 432 { 433 WARN_ON(1); 434 } 435