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 #include <asm/setup.h>
  37
  38 #include "mmu_decl.h"
  39
  40 unsigned long ioremap_base;
  41 unsigned long ioremap_bot;
  42 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
  43
  44 #ifdef CONFIG_6xx
  45 #define HAVE_BATS       1
  46 #endif
  47
  48 #if defined(CONFIG_FSL_BOOKE)
  49 #define HAVE_TLBCAM     1
  50 #endif
  51
  52 extern char etext[], _stext[];
  53
  54 #ifdef HAVE_BATS
  55 extern phys_addr_t v_mapped_by_bats(unsigned long va);
  56 extern unsigned long p_mapped_by_bats(phys_addr_t pa);
  57 void setbat(int index, unsigned long virt, phys_addr_t phys,
  58             unsigned int size, int flags);
  59
  60 #else /* !HAVE_BATS */
  61 #define v_mapped_by_bats(x)     (0UL)
  62 #define p_mapped_by_bats(x)     (0UL)
  63 #endif /* HAVE_BATS */
  64
  65 #ifdef HAVE_TLBCAM
  66 extern unsigned int tlbcam_index;
  67 extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
  68 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
  69 #else /* !HAVE_TLBCAM */
  70 #define v_mapped_by_tlbcam(x)   (0UL)
  71 #define p_mapped_by_tlbcam(x)   (0UL)
  72 #endif /* HAVE_TLBCAM */
  73
  74 #define PGDIR_ORDER     (32 + PGD_T_LOG2 - PGDIR_SHIFT)
  75
  76 pgd_t *pgd_alloc(struct mm_struct *mm)
  77 {
  78         pgd_t *ret;
  79
  80         /* pgdir take page or two with 4K pages and a page fraction otherwise */
  81 #ifndef CONFIG_PPC_4K_PAGES
  82         ret = kzalloc(1 << PGDIR_ORDER, GFP_KERNEL);
  83 #else
  84         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  85                         PGDIR_ORDER - PAGE_SHIFT);
  86 #endif
  87         return ret;
  88 }
  89
  90 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  91 {
  92 #ifndef CONFIG_PPC_4K_PAGES
  93         kfree((void *)pgd);
  94 #else
  95         free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
  96 #endif
  97 }
  98
  99 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 100 {
 101         pte_t *pte;
 102         extern int mem_init_done;
 103
 104         if (mem_init_done) {
 105                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 106         } else {
 107                 pte = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
 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         if (!pgtable_page_ctor(ptepage)) {
 124                 __free_page(ptepage);
 125                 return NULL;
 126         }
 127         return ptepage;
 128 }
 129
 130 void __iomem *
 131 ioremap(phys_addr_t addr, unsigned long size)
 132 {
 133         return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
 134                                 __builtin_return_address(0));
 135 }
 136 EXPORT_SYMBOL(ioremap);
 137
 138 void __iomem *
 139 ioremap_wc(phys_addr_t addr, unsigned long size)
 140 {
 141         return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
 142                                 __builtin_return_address(0));
 143 }
 144 EXPORT_SYMBOL(ioremap_wc);
 145
 146 void __iomem *
 147 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
 148 {
 149         /* writeable implies dirty for kernel addresses */
 150         if (flags & _PAGE_RW)
 151                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 152
 153         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 154         flags &= ~(_PAGE_USER | _PAGE_EXEC);
 155
 156 #ifdef _PAGE_BAP_SR
 157         /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
 158          * which means that we just cleared supervisor access... oops ;-) This
 159          * restores it
 160          */
 161         flags |= _PAGE_BAP_SR;
 162 #endif
 163
 164         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 165 }
 166 EXPORT_SYMBOL(ioremap_prot);
 167
 168 void __iomem *
 169 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 170 {
 171         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 172 }
 173
 174 void __iomem *
 175 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
 176                  void *caller)
 177 {
 178         unsigned long v, i;
 179         phys_addr_t p;
 180         int err;
 181
 182         /* Make sure we have the base flags */
 183         if ((flags & _PAGE_PRESENT) == 0)
 184                 flags |= PAGE_KERNEL;
 185
 186         /* Non-cacheable page cannot be coherent */
 187         if (flags & _PAGE_NO_CACHE)
 188                 flags &= ~_PAGE_COHERENT;
 189
 190         /*
 191          * Choose an address to map it to.
 192          * Once the vmalloc system is running, we use it.
 193          * Before then, we use space going down from ioremap_base
 194          * (ioremap_bot records where we're up to).
 195          */
 196         p = addr & PAGE_MASK;
 197         size = PAGE_ALIGN(addr + size) - p;
 198
 199         /*
 200          * If the address lies within the first 16 MB, assume it's in ISA
 201          * memory space
 202          */
 203         if (p < 16*1024*1024)
 204                 p += _ISA_MEM_BASE;
 205
 206 #ifndef CONFIG_CRASH_DUMP
 207         /*
 208          * Don't allow anybody to remap normal RAM that we're using.
 209          * mem_init() sets high_memory so only do the check after that.
 210          */
 211         if (mem_init_done && (p < virt_to_phys(high_memory)) &&
 212             !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
 213                 printk("__ioremap(): phys addr 0x%llx is RAM lr %pf\n",
 214                        (unsigned long long)p, __builtin_return_address(0));
 215                 return NULL;
 216         }
 217 #endif
 218
 219         if (size == 0)
 220                 return NULL;
 221
 222         /*
 223          * Is it already mapped?  Perhaps overlapped by a previous
 224          * BAT mapping.  If the whole area is mapped then we're done,
 225          * otherwise remap it since we want to keep the virt addrs for
 226          * each request contiguous.
 227          *
 228          * We make the assumption here that if the bottom and top
 229          * of the range we want are mapped then it's mapped to the
 230          * same virt address (and this is contiguous).
 231          *  -- Cort
 232          */
 233         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 234                 goto out;
 235
 236         if ((v = p_mapped_by_tlbcam(p)))
 237                 goto out;
 238
 239         if (mem_init_done) {
 240                 struct vm_struct *area;
 241                 area = get_vm_area_caller(size, VM_IOREMAP, caller);
 242                 if (area == 0)
 243                         return NULL;
 244                 area->phys_addr = p;
 245                 v = (unsigned long) area->addr;
 246         } else {
 247                 v = (ioremap_bot -= size);
 248         }
 249
 250         /*
 251          * Should check if it is a candidate for a BAT mapping
 252          */
 253
 254         err = 0;
 255         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 256                 err = map_page(v+i, p+i, flags);
 257         if (err) {
 258                 if (mem_init_done)
 259                         vunmap((void *)v);
 260                 return NULL;
 261         }
 262
 263 out:
 264         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 265 }
 266 EXPORT_SYMBOL(__ioremap);
 267
 268 void iounmap(volatile void __iomem *addr)
 269 {
 270         /*
 271          * If mapped by BATs then there is nothing to do.
 272          * Calling vfree() generates a benign warning.
 273          */
 274         if (v_mapped_by_bats((unsigned long)addr)) return;
 275
 276         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 277                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 278 }
 279 EXPORT_SYMBOL(iounmap);
 280
 281 int map_page(unsigned long va, phys_addr_t pa, int flags)
 282 {
 283         pmd_t *pd;
 284         pte_t *pg;
 285         int err = -ENOMEM;
 286
 287         /* Use upper 10 bits of VA to index the first level map */
 288         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 289         /* Use middle 10 bits of VA to index the second-level map */
 290         pg = pte_alloc_kernel(pd, va);
 291         if (pg != 0) {
 292                 err = 0;
 293                 /* The PTE should never be already set nor present in the
 294                  * hash table
 295                  */
 296                 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
 297                        flags);
 298                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 299                                                      __pgprot(flags)));
 300         }
 301         smp_wmb();
 302         return err;
 303 }
 304
 305 /*
 306  * Map in a chunk of physical memory starting at start.
 307  */
 308 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 309 {
 310         unsigned long v, s, f;
 311         phys_addr_t p;
 312         int ktext;
 313
 314         s = offset;
 315         v = PAGE_OFFSET + s;
 316         p = memstart_addr + s;
 317         for (; s < top; s += PAGE_SIZE) {
 318                 ktext = ((char *) v >= _stext && (char *) v < etext);
 319                 f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL;
 320                 map_page(v, p, f);
 321 #ifdef CONFIG_PPC_STD_MMU_32
 322                 if (ktext)
 323                         hash_preload(&init_mm, v, 0, 0x300);
 324 #endif
 325                 v += PAGE_SIZE;
 326                 p += PAGE_SIZE;
 327         }
 328 }
 329
 330 void __init mapin_ram(void)
 331 {
 332         unsigned long s, top;
 333
 334 #ifndef CONFIG_WII
 335         top = total_lowmem;
 336         s = mmu_mapin_ram(top);
 337         __mapin_ram_chunk(s, top);
 338 #else
 339         if (!wii_hole_size) {
 340                 s = mmu_mapin_ram(total_lowmem);
 341                 __mapin_ram_chunk(s, total_lowmem);
 342         } else {
 343                 top = wii_hole_start;
 344                 s = mmu_mapin_ram(top);
 345                 __mapin_ram_chunk(s, top);
 346
 347                 top = memblock_end_of_DRAM();
 348                 s = wii_mmu_mapin_mem2(top);
 349                 __mapin_ram_chunk(s, top);
 350         }
 351 #endif
 352 }
 353
 354 /* Scan the real Linux page tables and return a PTE pointer for
 355  * a virtual address in a context.
 356  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 357  * the PTE pointer is unmodified if PTE is not found.
 358  */
 359 int
 360 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 361 {
 362         pgd_t   *pgd;
 363         pud_t   *pud;
 364         pmd_t   *pmd;
 365         pte_t   *pte;
 366         int     retval = 0;
 367
 368         pgd = pgd_offset(mm, addr & PAGE_MASK);
 369         if (pgd) {
 370                 pud = pud_offset(pgd, addr & PAGE_MASK);
 371                 if (pud && pud_present(*pud)) {
 372                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 373                         if (pmd_present(*pmd)) {
 374                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 375                                 if (pte) {
 376                                         retval = 1;
 377                                         *ptep = pte;
 378                                         if (pmdp)
 379                                                 *pmdp = pmd;
 380                                         /* XXX caller needs to do pte_unmap, yuck */
 381                                 }
 382                         }
 383                 }
 384         }
 385         return(retval);
 386 }
 387
 388 #ifdef CONFIG_DEBUG_PAGEALLOC
 389
 390 static int __change_page_attr(struct page *page, pgprot_t prot)
 391 {
 392         pte_t *kpte;
 393         pmd_t *kpmd;
 394         unsigned long address;
 395
 396         BUG_ON(PageHighMem(page));
 397         address = (unsigned long)page_address(page);
 398
 399         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 400                 return 0;
 401         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 402                 return -EINVAL;
 403         __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
 404         wmb();
 405         flush_tlb_page(NULL, address);
 406         pte_unmap(kpte);
 407
 408         return 0;
 409 }
 410
 411 /*
 412  * Change the page attributes of an page in the linear mapping.
 413  *
 414  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 415  */
 416 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 417 {
 418         int i, err = 0;
 419         unsigned long flags;
 420
 421         local_irq_save(flags);
 422         for (i = 0; i < numpages; i++, page++) {
 423                 err = __change_page_attr(page, prot);
 424                 if (err)
 425                         break;
 426         }
 427         local_irq_restore(flags);
 428         return err;
 429 }
 430
 431
 432 void __kernel_map_pages(struct page *page, int numpages, int enable)
 433 {
 434         if (PageHighMem(page))
 435                 return;
 436
 437         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 438 }
 439 #endif /* CONFIG_DEBUG_PAGEALLOC */
 440
 441 static int fixmaps;
 442
 443 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 444 {
 445         unsigned long address = __fix_to_virt(idx);
 446
 447         if (idx >= __end_of_fixed_addresses) {
 448                 BUG();
 449                 return;
 450         }
 451
 452         map_page(address, phys, pgprot_val(flags));
 453         fixmaps++;
 454 }
 455
 456 void __this_fixmap_does_not_exist(void)
 457 {
 458         WARN_ON(1);
 459 }