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 #include <asm/sections.h> 38 39 #include "mmu_decl.h" 40 41 unsigned long ioremap_bot; 42 EXPORT_SYMBOL(ioremap_bot); /* aka VMALLOC_END */ 43 44 extern char etext[], _stext[], _sinittext[], _einittext[]; 45 46 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) 47 { 48 pte_t *pte; 49 50 if (slab_is_available()) { 51 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO); 52 } else { 53 pte = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE)); 54 if (pte) 55 clear_page(pte); 56 } 57 return pte; 58 } 59 60 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) 61 { 62 struct page *ptepage; 63 64 gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT; 65 66 ptepage = alloc_pages(flags, 0); 67 if (!ptepage) 68 return NULL; 69 if (!pgtable_page_ctor(ptepage)) { 70 __free_page(ptepage); 71 return NULL; 72 } 73 return ptepage; 74 } 75 76 void __iomem * 77 ioremap(phys_addr_t addr, unsigned long size) 78 { 79 pgprot_t prot = pgprot_noncached(PAGE_KERNEL); 80 81 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 82 } 83 EXPORT_SYMBOL(ioremap); 84 85 void __iomem * 86 ioremap_wc(phys_addr_t addr, unsigned long size) 87 { 88 pgprot_t prot = pgprot_noncached_wc(PAGE_KERNEL); 89 90 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 91 } 92 EXPORT_SYMBOL(ioremap_wc); 93 94 void __iomem * 95 ioremap_wt(phys_addr_t addr, unsigned long size) 96 { 97 pgprot_t prot = pgprot_cached_wthru(PAGE_KERNEL); 98 99 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 100 } 101 EXPORT_SYMBOL(ioremap_wt); 102 103 void __iomem * 104 ioremap_coherent(phys_addr_t addr, unsigned long size) 105 { 106 pgprot_t prot = pgprot_cached(PAGE_KERNEL); 107 108 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 109 } 110 EXPORT_SYMBOL(ioremap_coherent); 111 112 void __iomem * 113 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags) 114 { 115 pte_t pte = __pte(flags); 116 117 /* writeable implies dirty for kernel addresses */ 118 if (pte_write(pte)) 119 pte = pte_mkdirty(pte); 120 121 /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */ 122 pte = pte_exprotect(pte); 123 pte = pte_mkprivileged(pte); 124 125 return __ioremap_caller(addr, size, pte_pgprot(pte), __builtin_return_address(0)); 126 } 127 EXPORT_SYMBOL(ioremap_prot); 128 129 void __iomem * 130 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags) 131 { 132 return __ioremap_caller(addr, size, __pgprot(flags), __builtin_return_address(0)); 133 } 134 135 void __iomem * 136 __ioremap_caller(phys_addr_t addr, unsigned long size, pgprot_t prot, void *caller) 137 { 138 unsigned long v, i; 139 phys_addr_t p; 140 int err; 141 142 /* 143 * Choose an address to map it to. 144 * Once the vmalloc system is running, we use it. 145 * Before then, we use space going down from IOREMAP_TOP 146 * (ioremap_bot records where we're up to). 147 */ 148 p = addr & PAGE_MASK; 149 size = PAGE_ALIGN(addr + size) - p; 150 151 /* 152 * If the address lies within the first 16 MB, assume it's in ISA 153 * memory space 154 */ 155 if (p < 16*1024*1024) 156 p += _ISA_MEM_BASE; 157 158 #ifndef CONFIG_CRASH_DUMP 159 /* 160 * Don't allow anybody to remap normal RAM that we're using. 161 * mem_init() sets high_memory so only do the check after that. 162 */ 163 if (slab_is_available() && (p < virt_to_phys(high_memory)) && 164 page_is_ram(__phys_to_pfn(p))) { 165 printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n", 166 (unsigned long long)p, __builtin_return_address(0)); 167 return NULL; 168 } 169 #endif 170 171 if (size == 0) 172 return NULL; 173 174 /* 175 * Is it already mapped? Perhaps overlapped by a previous 176 * mapping. 177 */ 178 v = p_block_mapped(p); 179 if (v) 180 goto out; 181 182 if (slab_is_available()) { 183 struct vm_struct *area; 184 area = get_vm_area_caller(size, VM_IOREMAP, caller); 185 if (area == 0) 186 return NULL; 187 area->phys_addr = p; 188 v = (unsigned long) area->addr; 189 } else { 190 v = (ioremap_bot -= size); 191 } 192 193 /* 194 * Should check if it is a candidate for a BAT mapping 195 */ 196 197 err = 0; 198 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 199 err = map_kernel_page(v + i, p + i, prot); 200 if (err) { 201 if (slab_is_available()) 202 vunmap((void *)v); 203 return NULL; 204 } 205 206 out: 207 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 208 } 209 EXPORT_SYMBOL(__ioremap); 210 211 void iounmap(volatile void __iomem *addr) 212 { 213 /* 214 * If mapped by BATs then there is nothing to do. 215 * Calling vfree() generates a benign warning. 216 */ 217 if (v_block_mapped((unsigned long)addr)) 218 return; 219 220 if (addr > high_memory && (unsigned long) addr < ioremap_bot) 221 vunmap((void *) (PAGE_MASK & (unsigned long)addr)); 222 } 223 EXPORT_SYMBOL(iounmap); 224 225 int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot) 226 { 227 pmd_t *pd; 228 pte_t *pg; 229 int err = -ENOMEM; 230 231 /* Use upper 10 bits of VA to index the first level map */ 232 pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va); 233 /* Use middle 10 bits of VA to index the second-level map */ 234 pg = pte_alloc_kernel(pd, va); 235 if (pg != 0) { 236 err = 0; 237 /* The PTE should never be already set nor present in the 238 * hash table 239 */ 240 BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot)); 241 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot)); 242 } 243 smp_wmb(); 244 return err; 245 } 246 247 /* 248 * Map in a chunk of physical memory starting at start. 249 */ 250 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top) 251 { 252 unsigned long v, s; 253 phys_addr_t p; 254 int ktext; 255 256 s = offset; 257 v = PAGE_OFFSET + s; 258 p = memstart_addr + s; 259 for (; s < top; s += PAGE_SIZE) { 260 ktext = ((char *)v >= _stext && (char *)v < etext) || 261 ((char *)v >= _sinittext && (char *)v < _einittext); 262 map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL); 263 #ifdef CONFIG_PPC_STD_MMU_32 264 if (ktext) 265 hash_preload(&init_mm, v, false, 0x300); 266 #endif 267 v += PAGE_SIZE; 268 p += PAGE_SIZE; 269 } 270 } 271 272 void __init mapin_ram(void) 273 { 274 unsigned long s, top; 275 276 #ifndef CONFIG_WII 277 top = total_lowmem; 278 s = mmu_mapin_ram(top); 279 __mapin_ram_chunk(s, top); 280 #else 281 if (!wii_hole_size) { 282 s = mmu_mapin_ram(total_lowmem); 283 __mapin_ram_chunk(s, total_lowmem); 284 } else { 285 top = wii_hole_start; 286 s = mmu_mapin_ram(top); 287 __mapin_ram_chunk(s, top); 288 289 top = memblock_end_of_DRAM(); 290 s = wii_mmu_mapin_mem2(top); 291 __mapin_ram_chunk(s, top); 292 } 293 #endif 294 } 295 296 /* Scan the real Linux page tables and return a PTE pointer for 297 * a virtual address in a context. 298 * Returns true (1) if PTE was found, zero otherwise. The pointer to 299 * the PTE pointer is unmodified if PTE is not found. 300 */ 301 static int 302 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) 303 { 304 pgd_t *pgd; 305 pud_t *pud; 306 pmd_t *pmd; 307 pte_t *pte; 308 int retval = 0; 309 310 pgd = pgd_offset(mm, addr & PAGE_MASK); 311 if (pgd) { 312 pud = pud_offset(pgd, addr & PAGE_MASK); 313 if (pud && pud_present(*pud)) { 314 pmd = pmd_offset(pud, addr & PAGE_MASK); 315 if (pmd_present(*pmd)) { 316 pte = pte_offset_map(pmd, addr & PAGE_MASK); 317 if (pte) { 318 retval = 1; 319 *ptep = pte; 320 if (pmdp) 321 *pmdp = pmd; 322 /* XXX caller needs to do pte_unmap, yuck */ 323 } 324 } 325 } 326 } 327 return(retval); 328 } 329 330 static int __change_page_attr_noflush(struct page *page, pgprot_t prot) 331 { 332 pte_t *kpte; 333 pmd_t *kpmd; 334 unsigned long address; 335 336 BUG_ON(PageHighMem(page)); 337 address = (unsigned long)page_address(page); 338 339 if (v_block_mapped(address)) 340 return 0; 341 if (!get_pteptr(&init_mm, address, &kpte, &kpmd)) 342 return -EINVAL; 343 __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0); 344 pte_unmap(kpte); 345 346 return 0; 347 } 348 349 /* 350 * Change the page attributes of an page in the linear mapping. 351 * 352 * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY 353 */ 354 static int change_page_attr(struct page *page, int numpages, pgprot_t prot) 355 { 356 int i, err = 0; 357 unsigned long flags; 358 struct page *start = page; 359 360 local_irq_save(flags); 361 for (i = 0; i < numpages; i++, page++) { 362 err = __change_page_attr_noflush(page, prot); 363 if (err) 364 break; 365 } 366 wmb(); 367 local_irq_restore(flags); 368 flush_tlb_kernel_range((unsigned long)page_address(start), 369 (unsigned long)page_address(page)); 370 return err; 371 } 372 373 void mark_initmem_nx(void) 374 { 375 struct page *page = virt_to_page(_sinittext); 376 unsigned long numpages = PFN_UP((unsigned long)_einittext) - 377 PFN_DOWN((unsigned long)_sinittext); 378 379 change_page_attr(page, numpages, PAGE_KERNEL); 380 } 381 382 #ifdef CONFIG_STRICT_KERNEL_RWX 383 void mark_rodata_ro(void) 384 { 385 struct page *page; 386 unsigned long numpages; 387 388 page = virt_to_page(_stext); 389 numpages = PFN_UP((unsigned long)_etext) - 390 PFN_DOWN((unsigned long)_stext); 391 392 change_page_attr(page, numpages, PAGE_KERNEL_ROX); 393 /* 394 * mark .rodata as read only. Use __init_begin rather than __end_rodata 395 * to cover NOTES and EXCEPTION_TABLE. 396 */ 397 page = virt_to_page(__start_rodata); 398 numpages = PFN_UP((unsigned long)__init_begin) - 399 PFN_DOWN((unsigned long)__start_rodata); 400 401 change_page_attr(page, numpages, PAGE_KERNEL_RO); 402 } 403 #endif 404 405 #ifdef CONFIG_DEBUG_PAGEALLOC 406 void __kernel_map_pages(struct page *page, int numpages, int enable) 407 { 408 if (PageHighMem(page)) 409 return; 410 411 change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); 412 } 413 #endif /* CONFIG_DEBUG_PAGEALLOC */ 414