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 30 #include <asm/pgtable.h> 31 #include <asm/pgalloc.h> 32 #include <asm/fixmap.h> 33 #include <asm/io.h> 34 35 #include "mmu_decl.h" 36 37 unsigned long ioremap_base; 38 unsigned long ioremap_bot; 39 EXPORT_SYMBOL(ioremap_bot); /* aka VMALLOC_END */ 40 41 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3) 42 #define HAVE_BATS 1 43 #endif 44 45 #if defined(CONFIG_FSL_BOOKE) 46 #define HAVE_TLBCAM 1 47 #endif 48 49 extern char etext[], _stext[]; 50 51 #ifdef HAVE_BATS 52 extern phys_addr_t v_mapped_by_bats(unsigned long va); 53 extern unsigned long p_mapped_by_bats(phys_addr_t pa); 54 void setbat(int index, unsigned long virt, phys_addr_t phys, 55 unsigned int size, int flags); 56 57 #else /* !HAVE_BATS */ 58 #define v_mapped_by_bats(x) (0UL) 59 #define p_mapped_by_bats(x) (0UL) 60 #endif /* HAVE_BATS */ 61 62 #ifdef HAVE_TLBCAM 63 extern unsigned int tlbcam_index; 64 extern phys_addr_t v_mapped_by_tlbcam(unsigned long va); 65 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa); 66 #else /* !HAVE_TLBCAM */ 67 #define v_mapped_by_tlbcam(x) (0UL) 68 #define p_mapped_by_tlbcam(x) (0UL) 69 #endif /* HAVE_TLBCAM */ 70 71 #define PGDIR_ORDER (32 + PGD_T_LOG2 - PGDIR_SHIFT) 72 73 pgd_t *pgd_alloc(struct mm_struct *mm) 74 { 75 pgd_t *ret; 76 77 /* pgdir take page or two with 4K pages and a page fraction otherwise */ 78 #ifndef CONFIG_PPC_4K_PAGES 79 ret = (pgd_t *)kzalloc(1 << PGDIR_ORDER, GFP_KERNEL); 80 #else 81 ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 82 PGDIR_ORDER - PAGE_SHIFT); 83 #endif 84 return ret; 85 } 86 87 void pgd_free(struct mm_struct *mm, pgd_t *pgd) 88 { 89 #ifndef CONFIG_PPC_4K_PAGES 90 kfree((void *)pgd); 91 #else 92 free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT); 93 #endif 94 } 95 96 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) 97 { 98 pte_t *pte; 99 extern int mem_init_done; 100 extern void *early_get_page(void); 101 102 if (mem_init_done) { 103 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO); 104 } else { 105 pte = (pte_t *)early_get_page(); 106 if (pte) 107 clear_page(pte); 108 } 109 return pte; 110 } 111 112 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) 113 { 114 struct page *ptepage; 115 116 #ifdef CONFIG_HIGHPTE 117 gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT | __GFP_ZERO; 118 #else 119 gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO; 120 #endif 121 122 ptepage = alloc_pages(flags, 0); 123 if (!ptepage) 124 return NULL; 125 pgtable_page_ctor(ptepage); 126 return ptepage; 127 } 128 129 void __iomem * 130 ioremap(phys_addr_t addr, unsigned long size) 131 { 132 return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED, 133 __builtin_return_address(0)); 134 } 135 EXPORT_SYMBOL(ioremap); 136 137 void __iomem * 138 ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags) 139 { 140 /* writeable implies dirty for kernel addresses */ 141 if (flags & _PAGE_RW) 142 flags |= _PAGE_DIRTY | _PAGE_HWWRITE; 143 144 /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */ 145 flags &= ~(_PAGE_USER | _PAGE_EXEC | _PAGE_HWEXEC); 146 147 return __ioremap_caller(addr, size, flags, __builtin_return_address(0)); 148 } 149 EXPORT_SYMBOL(ioremap_flags); 150 151 void __iomem * 152 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags) 153 { 154 return __ioremap_caller(addr, size, flags, __builtin_return_address(0)); 155 } 156 157 void __iomem * 158 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags, 159 void *caller) 160 { 161 unsigned long v, i; 162 phys_addr_t p; 163 int err; 164 165 /* Make sure we have the base flags */ 166 if ((flags & _PAGE_PRESENT) == 0) 167 flags |= PAGE_KERNEL; 168 169 /* Non-cacheable page cannot be coherent */ 170 if (flags & _PAGE_NO_CACHE) 171 flags &= ~_PAGE_COHERENT; 172 173 /* 174 * Choose an address to map it to. 175 * Once the vmalloc system is running, we use it. 176 * Before then, we use space going down from ioremap_base 177 * (ioremap_bot records where we're up to). 178 */ 179 p = addr & PAGE_MASK; 180 size = PAGE_ALIGN(addr + size) - p; 181 182 /* 183 * If the address lies within the first 16 MB, assume it's in ISA 184 * memory space 185 */ 186 if (p < 16*1024*1024) 187 p += _ISA_MEM_BASE; 188 189 #ifndef CONFIG_CRASH_DUMP 190 /* 191 * Don't allow anybody to remap normal RAM that we're using. 192 * mem_init() sets high_memory so only do the check after that. 193 */ 194 if (mem_init_done && (p < virt_to_phys(high_memory))) { 195 printk("__ioremap(): phys addr 0x%llx is RAM lr %p\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 * BAT mapping. If the whole area is mapped then we're done, 207 * otherwise remap it since we want to keep the virt addrs for 208 * each request contiguous. 209 * 210 * We make the assumption here that if the bottom and top 211 * of the range we want are mapped then it's mapped to the 212 * same virt address (and this is contiguous). 213 * -- Cort 214 */ 215 if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ ) 216 goto out; 217 218 if ((v = p_mapped_by_tlbcam(p))) 219 goto out; 220 221 if (mem_init_done) { 222 struct vm_struct *area; 223 area = get_vm_area_caller(size, VM_IOREMAP, caller); 224 if (area == 0) 225 return NULL; 226 v = (unsigned long) area->addr; 227 } else { 228 v = (ioremap_bot -= size); 229 } 230 231 /* 232 * Should check if it is a candidate for a BAT mapping 233 */ 234 235 err = 0; 236 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 237 err = map_page(v+i, p+i, flags); 238 if (err) { 239 if (mem_init_done) 240 vunmap((void *)v); 241 return NULL; 242 } 243 244 out: 245 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 246 } 247 EXPORT_SYMBOL(__ioremap); 248 249 void iounmap(volatile void __iomem *addr) 250 { 251 /* 252 * If mapped by BATs then there is nothing to do. 253 * Calling vfree() generates a benign warning. 254 */ 255 if (v_mapped_by_bats((unsigned long)addr)) return; 256 257 if (addr > high_memory && (unsigned long) addr < ioremap_bot) 258 vunmap((void *) (PAGE_MASK & (unsigned long)addr)); 259 } 260 EXPORT_SYMBOL(iounmap); 261 262 int map_page(unsigned long va, phys_addr_t pa, int flags) 263 { 264 pmd_t *pd; 265 pte_t *pg; 266 int err = -ENOMEM; 267 268 /* Use upper 10 bits of VA to index the first level map */ 269 pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va); 270 /* Use middle 10 bits of VA to index the second-level map */ 271 pg = pte_alloc_kernel(pd, va); 272 if (pg != 0) { 273 err = 0; 274 /* The PTE should never be already set nor present in the 275 * hash table 276 */ 277 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) && 278 flags); 279 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, 280 __pgprot(flags))); 281 } 282 return err; 283 } 284 285 /* 286 * Map in a big chunk of physical memory starting at PAGE_OFFSET. 287 */ 288 void __init mapin_ram(void) 289 { 290 unsigned long v, s, f; 291 phys_addr_t p; 292 int ktext; 293 294 s = mmu_mapin_ram(); 295 v = PAGE_OFFSET + s; 296 p = memstart_addr + s; 297 for (; s < total_lowmem; s += PAGE_SIZE) { 298 ktext = ((char *) v >= _stext && (char *) v < etext); 299 f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL; 300 map_page(v, p, f); 301 #ifdef CONFIG_PPC_STD_MMU_32 302 if (ktext) 303 hash_preload(&init_mm, v, 0, 0x300); 304 #endif 305 v += PAGE_SIZE; 306 p += PAGE_SIZE; 307 } 308 } 309 310 /* Scan the real Linux page tables and return a PTE pointer for 311 * a virtual address in a context. 312 * Returns true (1) if PTE was found, zero otherwise. The pointer to 313 * the PTE pointer is unmodified if PTE is not found. 314 */ 315 int 316 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) 317 { 318 pgd_t *pgd; 319 pud_t *pud; 320 pmd_t *pmd; 321 pte_t *pte; 322 int retval = 0; 323 324 pgd = pgd_offset(mm, addr & PAGE_MASK); 325 if (pgd) { 326 pud = pud_offset(pgd, addr & PAGE_MASK); 327 if (pud && pud_present(*pud)) { 328 pmd = pmd_offset(pud, addr & PAGE_MASK); 329 if (pmd_present(*pmd)) { 330 pte = pte_offset_map(pmd, addr & PAGE_MASK); 331 if (pte) { 332 retval = 1; 333 *ptep = pte; 334 if (pmdp) 335 *pmdp = pmd; 336 /* XXX caller needs to do pte_unmap, yuck */ 337 } 338 } 339 } 340 } 341 return(retval); 342 } 343 344 #ifdef CONFIG_DEBUG_PAGEALLOC 345 346 static int __change_page_attr(struct page *page, pgprot_t prot) 347 { 348 pte_t *kpte; 349 pmd_t *kpmd; 350 unsigned long address; 351 352 BUG_ON(PageHighMem(page)); 353 address = (unsigned long)page_address(page); 354 355 if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address)) 356 return 0; 357 if (!get_pteptr(&init_mm, address, &kpte, &kpmd)) 358 return -EINVAL; 359 set_pte_at(&init_mm, address, kpte, mk_pte(page, prot)); 360 wmb(); 361 #ifdef CONFIG_PPC_STD_MMU 362 flush_hash_pages(0, address, pmd_val(*kpmd), 1); 363 #else 364 flush_tlb_page(NULL, address); 365 #endif 366 pte_unmap(kpte); 367 368 return 0; 369 } 370 371 /* 372 * Change the page attributes of an page in the linear mapping. 373 * 374 * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY 375 */ 376 static int change_page_attr(struct page *page, int numpages, pgprot_t prot) 377 { 378 int i, err = 0; 379 unsigned long flags; 380 381 local_irq_save(flags); 382 for (i = 0; i < numpages; i++, page++) { 383 err = __change_page_attr(page, prot); 384 if (err) 385 break; 386 } 387 local_irq_restore(flags); 388 return err; 389 } 390 391 392 void kernel_map_pages(struct page *page, int numpages, int enable) 393 { 394 if (PageHighMem(page)) 395 return; 396 397 change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); 398 } 399 #endif /* CONFIG_DEBUG_PAGEALLOC */ 400 401 static int fixmaps; 402 unsigned long FIXADDR_TOP = (-PAGE_SIZE); 403 EXPORT_SYMBOL(FIXADDR_TOP); 404 405 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) 406 { 407 unsigned long address = __fix_to_virt(idx); 408 409 if (idx >= __end_of_fixed_addresses) { 410 BUG(); 411 return; 412 } 413 414 map_page(address, phys, pgprot_val(flags)); 415 fixmaps++; 416 } 417 418 void __this_fixmap_does_not_exist(void) 419 { 420 WARN_ON(1); 421 } 422