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