arch/powerpc/mm/pgtable_32.c

   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 }