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