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 #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
  37 #include "mmu_decl.h"
  38
  39 unsigned long ioremap_base;
  40 unsigned long ioremap_bot;
  41 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
  42
  43 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
  44 #define HAVE_BATS       1
  45 #endif
  46
  47 #if defined(CONFIG_FSL_BOOKE)
  48 #define HAVE_TLBCAM     1
  49 #endif
  50
  51 extern char etext[], _stext[];
  52
  53 #ifdef HAVE_BATS
  54 extern phys_addr_t v_mapped_by_bats(unsigned long va);
  55 extern unsigned long p_mapped_by_bats(phys_addr_t pa);
  56 void setbat(int index, unsigned long virt, phys_addr_t phys,
  57             unsigned int size, int flags);
  58
  59 #else /* !HAVE_BATS */
  60 #define v_mapped_by_bats(x)     (0UL)
  61 #define p_mapped_by_bats(x)     (0UL)
  62 #endif /* HAVE_BATS */
  63
  64 #ifdef HAVE_TLBCAM
  65 extern unsigned int tlbcam_index;
  66 extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
  67 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
  68 #else /* !HAVE_TLBCAM */
  69 #define v_mapped_by_tlbcam(x)   (0UL)
  70 #define p_mapped_by_tlbcam(x)   (0UL)
  71 #endif /* HAVE_TLBCAM */
  72
  73 #define PGDIR_ORDER     (32 + PGD_T_LOG2 - PGDIR_SHIFT)
  74
  75 pgd_t *pgd_alloc(struct mm_struct *mm)
  76 {
  77         pgd_t *ret;
  78
  79         /* pgdir take page or two with 4K pages and a page fraction otherwise */
  80 #ifndef CONFIG_PPC_4K_PAGES
  81         ret = kzalloc(1 << PGDIR_ORDER, GFP_KERNEL);
  82 #else
  83         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  84                         PGDIR_ORDER - PAGE_SHIFT);
  85 #endif
  86         return ret;
  87 }
  88
  89 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  90 {
  91 #ifndef CONFIG_PPC_4K_PAGES
  92         kfree((void *)pgd);
  93 #else
  94         free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
  95 #endif
  96 }
  97
  98 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  99 {
 100         pte_t *pte;
 101         extern int mem_init_done;
 102         extern void *early_get_page(void);
 103
 104         if (mem_init_done) {
 105                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 106         } else {
 107                 pte = (pte_t *)early_get_page();
 108                 if (pte)
 109                         clear_page(pte);
 110         }
 111         return pte;
 112 }
 113
 114 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 115 {
 116         struct page *ptepage;
 117
 118         gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
 119
 120         ptepage = alloc_pages(flags, 0);
 121         if (!ptepage)
 122                 return NULL;
 123         pgtable_page_ctor(ptepage);
 124         return ptepage;
 125 }
 126
 127 void __iomem *
 128 ioremap(phys_addr_t addr, unsigned long size)
 129 {
 130         return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
 131                                 __builtin_return_address(0));
 132 }
 133 EXPORT_SYMBOL(ioremap);
 134
 135 void __iomem *
 136 ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
 137 {
 138         /* writeable implies dirty for kernel addresses */
 139         if (flags & _PAGE_RW)
 140                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 141
 142         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 143         flags &= ~(_PAGE_USER | _PAGE_EXEC);
 144
 145 #ifdef _PAGE_BAP_SR
 146         /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
 147          * which means that we just cleared supervisor access... oops ;-) This
 148          * restores it
 149          */
 150         flags |= _PAGE_BAP_SR;
 151 #endif
 152
 153         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 154 }
 155 EXPORT_SYMBOL(ioremap_flags);
 156
 157 void __iomem *
 158 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 159 {
 160         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 161 }
 162
 163 void __iomem *
 164 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
 165                  void *caller)
 166 {
 167         unsigned long v, i;
 168         phys_addr_t p;
 169         int err;
 170
 171         /* Make sure we have the base flags */
 172         if ((flags & _PAGE_PRESENT) == 0)
 173                 flags |= PAGE_KERNEL;
 174
 175         /* Non-cacheable page cannot be coherent */
 176         if (flags & _PAGE_NO_CACHE)
 177                 flags &= ~_PAGE_COHERENT;
 178
 179         /*
 180          * Choose an address to map it to.
 181          * Once the vmalloc system is running, we use it.
 182          * Before then, we use space going down from ioremap_base
 183          * (ioremap_bot records where we're up to).
 184          */
 185         p = addr & PAGE_MASK;
 186         size = PAGE_ALIGN(addr + size) - p;
 187
 188         /*
 189          * If the address lies within the first 16 MB, assume it's in ISA
 190          * memory space
 191          */
 192         if (p < 16*1024*1024)
 193                 p += _ISA_MEM_BASE;
 194
 195 #ifndef CONFIG_CRASH_DUMP
 196         /*
 197          * Don't allow anybody to remap normal RAM that we're using.
 198          * mem_init() sets high_memory so only do the check after that.
 199          */
 200         if (mem_init_done && (p < virt_to_phys(high_memory)) &&
 201             !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
 202                 printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
 203                        (unsigned long long)p, __builtin_return_address(0));
 204                 return NULL;
 205         }
 206 #endif
 207
 208         if (size == 0)
 209                 return NULL;
 210
 211         /*
 212          * Is it already mapped?  Perhaps overlapped by a previous
 213          * BAT mapping.  If the whole area is mapped then we're done,
 214          * otherwise remap it since we want to keep the virt addrs for
 215          * each request contiguous.
 216          *
 217          * We make the assumption here that if the bottom and top
 218          * of the range we want are mapped then it's mapped to the
 219          * same virt address (and this is contiguous).
 220          *  -- Cort
 221          */
 222         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 223                 goto out;
 224
 225         if ((v = p_mapped_by_tlbcam(p)))
 226                 goto out;
 227
 228         if (mem_init_done) {
 229                 struct vm_struct *area;
 230                 area = get_vm_area_caller(size, VM_IOREMAP, caller);
 231                 if (area == 0)
 232                         return NULL;
 233                 area->phys_addr = p;
 234                 v = (unsigned long) area->addr;
 235         } else {
 236                 v = (ioremap_bot -= size);
 237         }
 238
 239         /*
 240          * Should check if it is a candidate for a BAT mapping
 241          */
 242
 243         err = 0;
 244         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 245                 err = map_page(v+i, p+i, flags);
 246         if (err) {
 247                 if (mem_init_done)
 248                         vunmap((void *)v);
 249                 return NULL;
 250         }
 251
 252 out:
 253         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 254 }
 255 EXPORT_SYMBOL(__ioremap);
 256
 257 void iounmap(volatile void __iomem *addr)
 258 {
 259         /*
 260          * If mapped by BATs then there is nothing to do.
 261          * Calling vfree() generates a benign warning.
 262          */
 263         if (v_mapped_by_bats((unsigned long)addr)) return;
 264
 265         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 266                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 267 }
 268 EXPORT_SYMBOL(iounmap);
 269
 270 int map_page(unsigned long va, phys_addr_t pa, int flags)
 271 {
 272         pmd_t *pd;
 273         pte_t *pg;
 274         int err = -ENOMEM;
 275
 276         /* Use upper 10 bits of VA to index the first level map */
 277         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 278         /* Use middle 10 bits of VA to index the second-level map */
 279         pg = pte_alloc_kernel(pd, va);
 280         if (pg != 0) {
 281                 err = 0;
 282                 /* The PTE should never be already set nor present in the
 283                  * hash table
 284                  */
 285                 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
 286                        flags);
 287                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 288                                                      __pgprot(flags)));
 289         }
 290         return err;
 291 }
 292
 293 /*
 294  * Map in a chunk of physical memory starting at start.
 295  */
 296 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 297 {
 298         unsigned long v, s, f;
 299         phys_addr_t p;
 300         int ktext;
 301
 302         s = offset;
 303         v = PAGE_OFFSET + s;
 304         p = memstart_addr + s;
 305         for (; s < top; s += PAGE_SIZE) {
 306                 ktext = ((char *) v >= _stext && (char *) v < etext);
 307                 f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL;
 308                 map_page(v, p, f);
 309 #ifdef CONFIG_PPC_STD_MMU_32
 310                 if (ktext)
 311                         hash_preload(&init_mm, v, 0, 0x300);
 312 #endif
 313                 v += PAGE_SIZE;
 314                 p += PAGE_SIZE;
 315         }
 316 }
 317
 318 void __init mapin_ram(void)
 319 {
 320         unsigned long s, top;
 321
 322 #ifndef CONFIG_WII
 323         top = total_lowmem;
 324         s = mmu_mapin_ram(top);
 325         __mapin_ram_chunk(s, top);
 326 #else
 327         if (!wii_hole_size) {
 328                 s = mmu_mapin_ram(total_lowmem);
 329                 __mapin_ram_chunk(s, total_lowmem);
 330         } else {
 331                 top = wii_hole_start;
 332                 s = mmu_mapin_ram(top);
 333                 __mapin_ram_chunk(s, top);
 334
 335                 top = memblock_end_of_DRAM();
 336                 s = wii_mmu_mapin_mem2(top);
 337                 __mapin_ram_chunk(s, top);
 338         }
 339 #endif
 340 }
 341
 342 /* Scan the real Linux page tables and return a PTE pointer for
 343  * a virtual address in a context.
 344  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 345  * the PTE pointer is unmodified if PTE is not found.
 346  */
 347 int
 348 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 349 {
 350         pgd_t   *pgd;
 351         pud_t   *pud;
 352         pmd_t   *pmd;
 353         pte_t   *pte;
 354         int     retval = 0;
 355
 356         pgd = pgd_offset(mm, addr & PAGE_MASK);
 357         if (pgd) {
 358                 pud = pud_offset(pgd, addr & PAGE_MASK);
 359                 if (pud && pud_present(*pud)) {
 360                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 361                         if (pmd_present(*pmd)) {
 362                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 363                                 if (pte) {
 364                                         retval = 1;
 365                                         *ptep = pte;
 366                                         if (pmdp)
 367                                                 *pmdp = pmd;
 368                                         /* XXX caller needs to do pte_unmap, yuck */
 369                                 }
 370                         }
 371                 }
 372         }
 373         return(retval);
 374 }
 375
 376 #ifdef CONFIG_DEBUG_PAGEALLOC
 377
 378 static int __change_page_attr(struct page *page, pgprot_t prot)
 379 {
 380         pte_t *kpte;
 381         pmd_t *kpmd;
 382         unsigned long address;
 383
 384         BUG_ON(PageHighMem(page));
 385         address = (unsigned long)page_address(page);
 386
 387         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 388                 return 0;
 389         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 390                 return -EINVAL;
 391         __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
 392         wmb();
 393         flush_tlb_page(NULL, address);
 394         pte_unmap(kpte);
 395
 396         return 0;
 397 }
 398
 399 /*
 400  * Change the page attributes of an page in the linear mapping.
 401  *
 402  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 403  */
 404 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 405 {
 406         int i, err = 0;
 407         unsigned long flags;
 408
 409         local_irq_save(flags);
 410         for (i = 0; i < numpages; i++, page++) {
 411                 err = __change_page_attr(page, prot);
 412                 if (err)
 413                         break;
 414         }
 415         local_irq_restore(flags);
 416         return err;
 417 }
 418
 419
 420 void kernel_map_pages(struct page *page, int numpages, int enable)
 421 {
 422         if (PageHighMem(page))
 423                 return;
 424
 425         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 426 }
 427 #endif /* CONFIG_DEBUG_PAGEALLOC */
 428
 429 static int fixmaps;
 430
 431 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 432 {
 433         unsigned long address = __fix_to_virt(idx);
 434
 435         if (idx >= __end_of_fixed_addresses) {
 436                 BUG();
 437                 return;
 438         }
 439
 440         map_page(address, phys, pgprot_val(flags));
 441         fixmaps++;
 442 }
 443
 444 void __this_fixmap_does_not_exist(void)
 445 {
 446         WARN_ON(1);
 447 }