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