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 #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(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED);
 133 }
 134 EXPORT_SYMBOL(ioremap);
 135
 136 void __iomem *
 137 ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
 138 {
 139         /* writeable implies dirty for kernel addresses */
 140         if (flags & _PAGE_RW)
 141                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 142
 143         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 144         flags &= ~(_PAGE_USER | _PAGE_EXEC | _PAGE_HWEXEC);
 145
 146         return __ioremap(addr, size, flags);
 147 }
 148 EXPORT_SYMBOL(ioremap_flags);
 149
 150 void __iomem *
 151 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 152 {
 153         unsigned long v, i;
 154         phys_addr_t p;
 155         int err;
 156
 157         /* Make sure we have the base flags */
 158         if ((flags & _PAGE_PRESENT) == 0)
 159                 flags |= _PAGE_KERNEL;
 160
 161         /* Non-cacheable page cannot be coherent */
 162         if (flags & _PAGE_NO_CACHE)
 163                 flags &= ~_PAGE_COHERENT;
 164
 165         /*
 166          * Choose an address to map it to.
 167          * Once the vmalloc system is running, we use it.
 168          * Before then, we use space going down from ioremap_base
 169          * (ioremap_bot records where we're up to).
 170          */
 171         p = addr & PAGE_MASK;
 172         size = PAGE_ALIGN(addr + size) - p;
 173
 174         /*
 175          * If the address lies within the first 16 MB, assume it's in ISA
 176          * memory space
 177          */
 178         if (p < 16*1024*1024)
 179                 p += _ISA_MEM_BASE;
 180
 181 #ifndef CONFIG_CRASH_DUMP
 182         /*
 183          * Don't allow anybody to remap normal RAM that we're using.
 184          * mem_init() sets high_memory so only do the check after that.
 185          */
 186         if (mem_init_done && (p < virt_to_phys(high_memory))) {
 187                 printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
 188                        (unsigned long long)p, __builtin_return_address(0));
 189                 return NULL;
 190         }
 191 #endif
 192
 193         if (size == 0)
 194                 return NULL;
 195
 196         /*
 197          * Is it already mapped?  Perhaps overlapped by a previous
 198          * BAT mapping.  If the whole area is mapped then we're done,
 199          * otherwise remap it since we want to keep the virt addrs for
 200          * each request contiguous.
 201          *
 202          * We make the assumption here that if the bottom and top
 203          * of the range we want are mapped then it's mapped to the
 204          * same virt address (and this is contiguous).
 205          *  -- Cort
 206          */
 207         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 208                 goto out;
 209
 210         if ((v = p_mapped_by_tlbcam(p)))
 211                 goto out;
 212
 213         if (mem_init_done) {
 214                 struct vm_struct *area;
 215                 area = get_vm_area(size, VM_IOREMAP);
 216                 if (area == 0)
 217                         return NULL;
 218                 v = (unsigned long) area->addr;
 219         } else {
 220                 v = (ioremap_bot -= size);
 221         }
 222
 223         /*
 224          * Should check if it is a candidate for a BAT mapping
 225          */
 226
 227         err = 0;
 228         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 229                 err = map_page(v+i, p+i, flags);
 230         if (err) {
 231                 if (mem_init_done)
 232                         vunmap((void *)v);
 233                 return NULL;
 234         }
 235
 236 out:
 237         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 238 }
 239 EXPORT_SYMBOL(__ioremap);
 240
 241 void iounmap(volatile void __iomem *addr)
 242 {
 243         /*
 244          * If mapped by BATs then there is nothing to do.
 245          * Calling vfree() generates a benign warning.
 246          */
 247         if (v_mapped_by_bats((unsigned long)addr)) return;
 248
 249         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 250                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 251 }
 252 EXPORT_SYMBOL(iounmap);
 253
 254 int map_page(unsigned long va, phys_addr_t pa, int flags)
 255 {
 256         pmd_t *pd;
 257         pte_t *pg;
 258         int err = -ENOMEM;
 259
 260         /* Use upper 10 bits of VA to index the first level map */
 261         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 262         /* Use middle 10 bits of VA to index the second-level map */
 263         pg = pte_alloc_kernel(pd, va);
 264         if (pg != 0) {
 265                 err = 0;
 266                 /* The PTE should never be already set nor present in the
 267                  * hash table
 268                  */
 269                 BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
 270                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 271                                                      __pgprot(flags)));
 272         }
 273         return err;
 274 }
 275
 276 /*
 277  * Map in a big chunk of physical memory starting at PAGE_OFFSET.
 278  */
 279 void __init mapin_ram(void)
 280 {
 281         unsigned long v, s, f;
 282         phys_addr_t p;
 283         int ktext;
 284
 285         s = mmu_mapin_ram();
 286         v = PAGE_OFFSET + s;
 287         p = memstart_addr + s;
 288         for (; s < total_lowmem; s += PAGE_SIZE) {
 289                 ktext = ((char *) v >= _stext && (char *) v < etext);
 290                 f = ktext ?_PAGE_RAM_TEXT : _PAGE_RAM;
 291                 map_page(v, p, f);
 292 #ifdef CONFIG_PPC_STD_MMU_32
 293                 if (ktext)
 294                         hash_preload(&init_mm, v, 0, 0x300);
 295 #endif
 296                 v += PAGE_SIZE;
 297                 p += PAGE_SIZE;
 298         }
 299 }
 300
 301 /* Scan the real Linux page tables and return a PTE pointer for
 302  * a virtual address in a context.
 303  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 304  * the PTE pointer is unmodified if PTE is not found.
 305  */
 306 int
 307 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 308 {
 309         pgd_t   *pgd;
 310         pud_t   *pud;
 311         pmd_t   *pmd;
 312         pte_t   *pte;
 313         int     retval = 0;
 314
 315         pgd = pgd_offset(mm, addr & PAGE_MASK);
 316         if (pgd) {
 317                 pud = pud_offset(pgd, addr & PAGE_MASK);
 318                 if (pud && pud_present(*pud)) {
 319                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 320                         if (pmd_present(*pmd)) {
 321                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 322                                 if (pte) {
 323                                         retval = 1;
 324                                         *ptep = pte;
 325                                         if (pmdp)
 326                                                 *pmdp = pmd;
 327                                         /* XXX caller needs to do pte_unmap, yuck */
 328                                 }
 329                         }
 330                 }
 331         }
 332         return(retval);
 333 }
 334
 335 #ifdef CONFIG_DEBUG_PAGEALLOC
 336
 337 static int __change_page_attr(struct page *page, pgprot_t prot)
 338 {
 339         pte_t *kpte;
 340         pmd_t *kpmd;
 341         unsigned long address;
 342
 343         BUG_ON(PageHighMem(page));
 344         address = (unsigned long)page_address(page);
 345
 346         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 347                 return 0;
 348         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 349                 return -EINVAL;
 350         set_pte_at(&init_mm, address, kpte, mk_pte(page, prot));
 351         wmb();
 352 #ifdef CONFIG_PPC_STD_MMU
 353         flush_hash_pages(0, address, pmd_val(*kpmd), 1);
 354 #else
 355         flush_tlb_page(NULL, address);
 356 #endif
 357         pte_unmap(kpte);
 358
 359         return 0;
 360 }
 361
 362 /*
 363  * Change the page attributes of an page in the linear mapping.
 364  *
 365  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 366  */
 367 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 368 {
 369         int i, err = 0;
 370         unsigned long flags;
 371
 372         local_irq_save(flags);
 373         for (i = 0; i < numpages; i++, page++) {
 374                 err = __change_page_attr(page, prot);
 375                 if (err)
 376                         break;
 377         }
 378         local_irq_restore(flags);
 379         return err;
 380 }
 381
 382
 383 void kernel_map_pages(struct page *page, int numpages, int enable)
 384 {
 385         if (PageHighMem(page))
 386                 return;
 387
 388         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 389 }
 390 #endif /* CONFIG_DEBUG_PAGEALLOC */
 391
 392 static int fixmaps;
 393 unsigned long FIXADDR_TOP = (-PAGE_SIZE);
 394 EXPORT_SYMBOL(FIXADDR_TOP);
 395
 396 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 397 {
 398         unsigned long address = __fix_to_virt(idx);
 399
 400         if (idx >= __end_of_fixed_addresses) {
 401                 BUG();
 402                 return;
 403         }
 404
 405         map_page(address, phys, pgprot_val(flags));
 406         fixmaps++;
 407 }
 408
 409 void __this_fixmap_does_not_exist(void)
 410 {
 411         WARN_ON(1);
 412 }