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 unsigned long v_mapped_by_tlbcam(unsigned long va);
  65 extern unsigned long p_mapped_by_tlbcam(unsigned long 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 #ifdef CONFIG_PTE_64BIT
  72 /* Some processors use an 8kB pgdir because they have 8-byte Linux PTEs. */
  73 #define PGDIR_ORDER     1
  74 #else
  75 #define PGDIR_ORDER     0
  76 #endif
  77
  78 pgd_t *pgd_alloc(struct mm_struct *mm)
  79 {
  80         pgd_t *ret;
  81
  82         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
  83         return ret;
  84 }
  85
  86 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  87 {
  88         free_pages((unsigned long)pgd, PGDIR_ORDER);
  89 }
  90
  91 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  92 {
  93         pte_t *pte;
  94         extern int mem_init_done;
  95         extern void *early_get_page(void);
  96
  97         if (mem_init_done) {
  98                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
  99         } else {
 100                 pte = (pte_t *)early_get_page();
 101                 if (pte)
 102                         clear_page(pte);
 103         }
 104         return pte;
 105 }
 106
 107 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 108 {
 109         struct page *ptepage;
 110
 111 #ifdef CONFIG_HIGHPTE
 112         gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT | __GFP_ZERO;
 113 #else
 114         gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
 115 #endif
 116
 117         ptepage = alloc_pages(flags, 0);
 118         if (!ptepage)
 119                 return NULL;
 120         pgtable_page_ctor(ptepage);
 121         return ptepage;
 122 }
 123
 124 void __iomem *
 125 ioremap(phys_addr_t addr, unsigned long size)
 126 {
 127         return __ioremap(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED);
 128 }
 129 EXPORT_SYMBOL(ioremap);
 130
 131 void __iomem *
 132 ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
 133 {
 134         /* writeable implies dirty for kernel addresses */
 135         if (flags & _PAGE_RW)
 136                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 137
 138         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 139         flags &= ~(_PAGE_USER | _PAGE_EXEC | _PAGE_HWEXEC);
 140
 141         return __ioremap(addr, size, flags);
 142 }
 143 EXPORT_SYMBOL(ioremap_flags);
 144
 145 void __iomem *
 146 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 147 {
 148         unsigned long v, i;
 149         phys_addr_t p;
 150         int err;
 151
 152         /* Make sure we have the base flags */
 153         if ((flags & _PAGE_PRESENT) == 0)
 154                 flags |= _PAGE_KERNEL;
 155
 156         /* Non-cacheable page cannot be coherent */
 157         if (flags & _PAGE_NO_CACHE)
 158                 flags &= ~_PAGE_COHERENT;
 159
 160         /*
 161          * Choose an address to map it to.
 162          * Once the vmalloc system is running, we use it.
 163          * Before then, we use space going down from ioremap_base
 164          * (ioremap_bot records where we're up to).
 165          */
 166         p = addr & PAGE_MASK;
 167         size = PAGE_ALIGN(addr + size) - p;
 168
 169         /*
 170          * If the address lies within the first 16 MB, assume it's in ISA
 171          * memory space
 172          */
 173         if (p < 16*1024*1024)
 174                 p += _ISA_MEM_BASE;
 175
 176         /*
 177          * Don't allow anybody to remap normal RAM that we're using.
 178          * mem_init() sets high_memory so only do the check after that.
 179          */
 180         if (mem_init_done && (p < virt_to_phys(high_memory))) {
 181                 printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
 182                        (unsigned long long)p, __builtin_return_address(0));
 183                 return NULL;
 184         }
 185
 186         if (size == 0)
 187                 return NULL;
 188
 189         /*
 190          * Is it already mapped?  Perhaps overlapped by a previous
 191          * BAT mapping.  If the whole area is mapped then we're done,
 192          * otherwise remap it since we want to keep the virt addrs for
 193          * each request contiguous.
 194          *
 195          * We make the assumption here that if the bottom and top
 196          * of the range we want are mapped then it's mapped to the
 197          * same virt address (and this is contiguous).
 198          *  -- Cort
 199          */
 200         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 201                 goto out;
 202
 203         if ((v = p_mapped_by_tlbcam(p)))
 204                 goto out;
 205
 206         if (mem_init_done) {
 207                 struct vm_struct *area;
 208                 area = get_vm_area(size, VM_IOREMAP);
 209                 if (area == 0)
 210                         return NULL;
 211                 v = (unsigned long) area->addr;
 212         } else {
 213                 v = (ioremap_bot -= size);
 214         }
 215
 216         /*
 217          * Should check if it is a candidate for a BAT mapping
 218          */
 219
 220         err = 0;
 221         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 222                 err = map_page(v+i, p+i, flags);
 223         if (err) {
 224                 if (mem_init_done)
 225                         vunmap((void *)v);
 226                 return NULL;
 227         }
 228
 229 out:
 230         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 231 }
 232 EXPORT_SYMBOL(__ioremap);
 233
 234 void iounmap(volatile void __iomem *addr)
 235 {
 236         /*
 237          * If mapped by BATs then there is nothing to do.
 238          * Calling vfree() generates a benign warning.
 239          */
 240         if (v_mapped_by_bats((unsigned long)addr)) return;
 241
 242         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 243                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 244 }
 245 EXPORT_SYMBOL(iounmap);
 246
 247 int map_page(unsigned long va, phys_addr_t pa, int flags)
 248 {
 249         pmd_t *pd;
 250         pte_t *pg;
 251         int err = -ENOMEM;
 252
 253         /* Use upper 10 bits of VA to index the first level map */
 254         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 255         /* Use middle 10 bits of VA to index the second-level map */
 256         pg = pte_alloc_kernel(pd, va);
 257         if (pg != 0) {
 258                 err = 0;
 259                 /* The PTE should never be already set nor present in the
 260                  * hash table
 261                  */
 262                 BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
 263                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 264                                                      __pgprot(flags)));
 265         }
 266         return err;
 267 }
 268
 269 /*
 270  * Map in a big chunk of physical memory starting at KERNELBASE.
 271  */
 272 void __init mapin_ram(void)
 273 {
 274         unsigned long v, s, f;
 275         phys_addr_t p;
 276         int ktext;
 277
 278         s = mmu_mapin_ram();
 279         v = KERNELBASE + s;
 280         p = memstart_addr + s;
 281         for (; s < total_lowmem; s += PAGE_SIZE) {
 282                 ktext = ((char *) v >= _stext && (char *) v < etext);
 283                 f = ktext ?_PAGE_RAM_TEXT : _PAGE_RAM;
 284                 map_page(v, p, f);
 285 #ifdef CONFIG_PPC_STD_MMU_32
 286                 if (ktext)
 287                         hash_preload(&init_mm, v, 0, 0x300);
 288 #endif
 289                 v += PAGE_SIZE;
 290                 p += PAGE_SIZE;
 291         }
 292 }
 293
 294 /* Scan the real Linux page tables and return a PTE pointer for
 295  * a virtual address in a context.
 296  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 297  * the PTE pointer is unmodified if PTE is not found.
 298  */
 299 int
 300 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 301 {
 302         pgd_t   *pgd;
 303         pud_t   *pud;
 304         pmd_t   *pmd;
 305         pte_t   *pte;
 306         int     retval = 0;
 307
 308         pgd = pgd_offset(mm, addr & PAGE_MASK);
 309         if (pgd) {
 310                 pud = pud_offset(pgd, addr & PAGE_MASK);
 311                 if (pud && pud_present(*pud)) {
 312                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 313                         if (pmd_present(*pmd)) {
 314                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 315                                 if (pte) {
 316                                         retval = 1;
 317                                         *ptep = pte;
 318                                         if (pmdp)
 319                                                 *pmdp = pmd;
 320                                         /* XXX caller needs to do pte_unmap, yuck */
 321                                 }
 322                         }
 323                 }
 324         }
 325         return(retval);
 326 }
 327
 328 #ifdef CONFIG_DEBUG_PAGEALLOC
 329
 330 static int __change_page_attr(struct page *page, pgprot_t prot)
 331 {
 332         pte_t *kpte;
 333         pmd_t *kpmd;
 334         unsigned long address;
 335
 336         BUG_ON(PageHighMem(page));
 337         address = (unsigned long)page_address(page);
 338
 339         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 340                 return 0;
 341         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 342                 return -EINVAL;
 343         set_pte_at(&init_mm, address, kpte, mk_pte(page, prot));
 344         wmb();
 345 #ifdef CONFIG_PPC_STD_MMU
 346         flush_hash_pages(0, address, pmd_val(*kpmd), 1);
 347 #else
 348         flush_tlb_page(NULL, address);
 349 #endif
 350         pte_unmap(kpte);
 351
 352         return 0;
 353 }
 354
 355 /*
 356  * Change the page attributes of an page in the linear mapping.
 357  *
 358  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 359  */
 360 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 361 {
 362         int i, err = 0;
 363         unsigned long flags;
 364
 365         local_irq_save(flags);
 366         for (i = 0; i < numpages; i++, page++) {
 367                 err = __change_page_attr(page, prot);
 368                 if (err)
 369                         break;
 370         }
 371         local_irq_restore(flags);
 372         return err;
 373 }
 374
 375
 376 void kernel_map_pages(struct page *page, int numpages, int enable)
 377 {
 378         if (PageHighMem(page))
 379                 return;
 380
 381         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 382 }
 383 #endif /* CONFIG_DEBUG_PAGEALLOC */
 384
 385 static int fixmaps;
 386 unsigned long FIXADDR_TOP = 0xfffff000;
 387 EXPORT_SYMBOL(FIXADDR_TOP);
 388
 389 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 390 {
 391         unsigned long address = __fix_to_virt(idx);
 392
 393         if (idx >= __end_of_fixed_addresses) {
 394                 BUG();
 395                 return;
 396         }
 397
 398         map_page(address, phys, pgprot_val(flags));
 399         fixmaps++;
 400 }
 401
 402 void __this_fixmap_does_not_exist(void)
 403 {
 404         WARN_ON(1);
 405 }