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 #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 phys_addr_t v_mapped_by_tlbcam(unsigned long va);
  64 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
  65 #else /* !HAVE_TLBCAM */
  66 #define v_mapped_by_tlbcam(x)   (0UL)
  67 #define p_mapped_by_tlbcam(x)   (0UL)
  68 #endif /* HAVE_TLBCAM */
  69
  70 #define PGDIR_ORDER     (32 + PGD_T_LOG2 - PGDIR_SHIFT)
  71
  72 #ifndef CONFIG_PPC_4K_PAGES
  73 static struct kmem_cache *pgtable_cache;
  74
  75 void pgtable_cache_init(void)
  76 {
  77         pgtable_cache = kmem_cache_create("PGDIR cache", 1 << PGDIR_ORDER,
  78                                           1 << PGDIR_ORDER, 0, NULL);
  79         if (pgtable_cache == NULL)
  80                 panic("Couldn't allocate pgtable caches");
  81 }
  82 #endif
  83
  84 pgd_t *pgd_alloc(struct mm_struct *mm)
  85 {
  86         pgd_t *ret;
  87
  88         /* pgdir take page or two with 4K pages and a page fraction otherwise */
  89 #ifndef CONFIG_PPC_4K_PAGES
  90         ret = kmem_cache_alloc(pgtable_cache, GFP_KERNEL | __GFP_ZERO);
  91 #else
  92         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  93                         PGDIR_ORDER - PAGE_SHIFT);
  94 #endif
  95         return ret;
  96 }
  97
  98 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  99 {
 100 #ifndef CONFIG_PPC_4K_PAGES
 101         kmem_cache_free(pgtable_cache, (void *)pgd);
 102 #else
 103         free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
 104 #endif
 105 }
 106
 107 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 108 {
 109         pte_t *pte;
 110
 111         if (slab_is_available()) {
 112                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 113         } else {
 114                 pte = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
 115                 if (pte)
 116                         clear_page(pte);
 117         }
 118         return pte;
 119 }
 120
 121 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 122 {
 123         struct page *ptepage;
 124
 125         gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
 126
 127         ptepage = alloc_pages(flags, 0);
 128         if (!ptepage)
 129                 return NULL;
 130         if (!pgtable_page_ctor(ptepage)) {
 131                 __free_page(ptepage);
 132                 return NULL;
 133         }
 134         return ptepage;
 135 }
 136
 137 void __iomem *
 138 ioremap(phys_addr_t addr, unsigned long size)
 139 {
 140         return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
 141                                 __builtin_return_address(0));
 142 }
 143 EXPORT_SYMBOL(ioremap);
 144
 145 void __iomem *
 146 ioremap_wc(phys_addr_t addr, unsigned long size)
 147 {
 148         return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
 149                                 __builtin_return_address(0));
 150 }
 151 EXPORT_SYMBOL(ioremap_wc);
 152
 153 void __iomem *
 154 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
 155 {
 156         /* writeable implies dirty for kernel addresses */
 157         if ((flags & (_PAGE_RW | _PAGE_RO)) != _PAGE_RO)
 158                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 159
 160         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 161         flags &= ~(_PAGE_USER | _PAGE_EXEC);
 162
 163 #ifdef _PAGE_BAP_SR
 164         /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
 165          * which means that we just cleared supervisor access... oops ;-) This
 166          * restores it
 167          */
 168         flags |= _PAGE_BAP_SR;
 169 #endif
 170
 171         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 172 }
 173 EXPORT_SYMBOL(ioremap_prot);
 174
 175 void __iomem *
 176 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 177 {
 178         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 179 }
 180
 181 void __iomem *
 182 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
 183                  void *caller)
 184 {
 185         unsigned long v, i;
 186         phys_addr_t p;
 187         int err;
 188
 189         /* Make sure we have the base flags */
 190         if ((flags & _PAGE_PRESENT) == 0)
 191                 flags |= pgprot_val(PAGE_KERNEL);
 192
 193         /* Non-cacheable page cannot be coherent */
 194         if (flags & _PAGE_NO_CACHE)
 195                 flags &= ~_PAGE_COHERENT;
 196
 197         /*
 198          * Choose an address to map it to.
 199          * Once the vmalloc system is running, we use it.
 200          * Before then, we use space going down from ioremap_base
 201          * (ioremap_bot records where we're up to).
 202          */
 203         p = addr & PAGE_MASK;
 204         size = PAGE_ALIGN(addr + size) - p;
 205
 206         /*
 207          * If the address lies within the first 16 MB, assume it's in ISA
 208          * memory space
 209          */
 210         if (p < 16*1024*1024)
 211                 p += _ISA_MEM_BASE;
 212
 213 #ifndef CONFIG_CRASH_DUMP
 214         /*
 215          * Don't allow anybody to remap normal RAM that we're using.
 216          * mem_init() sets high_memory so only do the check after that.
 217          */
 218         if (slab_is_available() && (p < virt_to_phys(high_memory)) &&
 219             !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
 220                 printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
 221                        (unsigned long long)p, __builtin_return_address(0));
 222                 return NULL;
 223         }
 224 #endif
 225
 226         if (size == 0)
 227                 return NULL;
 228
 229         /*
 230          * Is it already mapped?  Perhaps overlapped by a previous
 231          * BAT mapping.  If the whole area is mapped then we're done,
 232          * otherwise remap it since we want to keep the virt addrs for
 233          * each request contiguous.
 234          *
 235          * We make the assumption here that if the bottom and top
 236          * of the range we want are mapped then it's mapped to the
 237          * same virt address (and this is contiguous).
 238          *  -- Cort
 239          */
 240         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 241                 goto out;
 242
 243         if ((v = p_mapped_by_tlbcam(p)))
 244                 goto out;
 245
 246         if (slab_is_available()) {
 247                 struct vm_struct *area;
 248                 area = get_vm_area_caller(size, VM_IOREMAP, caller);
 249                 if (area == 0)
 250                         return NULL;
 251                 area->phys_addr = p;
 252                 v = (unsigned long) area->addr;
 253         } else {
 254                 v = (ioremap_bot -= size);
 255         }
 256
 257         /*
 258          * Should check if it is a candidate for a BAT mapping
 259          */
 260
 261         err = 0;
 262         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 263                 err = map_page(v+i, p+i, flags);
 264         if (err) {
 265                 if (slab_is_available())
 266                         vunmap((void *)v);
 267                 return NULL;
 268         }
 269
 270 out:
 271         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 272 }
 273 EXPORT_SYMBOL(__ioremap);
 274
 275 void iounmap(volatile void __iomem *addr)
 276 {
 277         /*
 278          * If mapped by BATs then there is nothing to do.
 279          * Calling vfree() generates a benign warning.
 280          */
 281         if (v_mapped_by_bats((unsigned long)addr)) return;
 282
 283         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 284                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 285 }
 286 EXPORT_SYMBOL(iounmap);
 287
 288 int map_page(unsigned long va, phys_addr_t pa, int flags)
 289 {
 290         pmd_t *pd;
 291         pte_t *pg;
 292         int err = -ENOMEM;
 293
 294         /* Use upper 10 bits of VA to index the first level map */
 295         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 296         /* Use middle 10 bits of VA to index the second-level map */
 297         pg = pte_alloc_kernel(pd, va);
 298         if (pg != 0) {
 299                 err = 0;
 300                 /* The PTE should never be already set nor present in the
 301                  * hash table
 302                  */
 303                 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
 304                        flags);
 305                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 306                                                      __pgprot(flags)));
 307         }
 308         smp_wmb();
 309         return err;
 310 }
 311
 312 /*
 313  * Map in a chunk of physical memory starting at start.
 314  */
 315 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 316 {
 317         unsigned long v, s, f;
 318         phys_addr_t p;
 319         int ktext;
 320
 321         s = offset;
 322         v = PAGE_OFFSET + s;
 323         p = memstart_addr + s;
 324         for (; s < top; s += PAGE_SIZE) {
 325                 ktext = ((char *) v >= _stext && (char *) v < etext);
 326                 f = ktext ? pgprot_val(PAGE_KERNEL_TEXT) : pgprot_val(PAGE_KERNEL);
 327                 map_page(v, p, f);
 328 #ifdef CONFIG_PPC_STD_MMU_32
 329                 if (ktext)
 330                         hash_preload(&init_mm, v, 0, 0x300);
 331 #endif
 332                 v += PAGE_SIZE;
 333                 p += PAGE_SIZE;
 334         }
 335 }
 336
 337 void __init mapin_ram(void)
 338 {
 339         unsigned long s, top;
 340
 341 #ifndef CONFIG_WII
 342         top = total_lowmem;
 343         s = mmu_mapin_ram(top);
 344         __mapin_ram_chunk(s, top);
 345 #else
 346         if (!wii_hole_size) {
 347                 s = mmu_mapin_ram(total_lowmem);
 348                 __mapin_ram_chunk(s, total_lowmem);
 349         } else {
 350                 top = wii_hole_start;
 351                 s = mmu_mapin_ram(top);
 352                 __mapin_ram_chunk(s, top);
 353
 354                 top = memblock_end_of_DRAM();
 355                 s = wii_mmu_mapin_mem2(top);
 356                 __mapin_ram_chunk(s, top);
 357         }
 358 #endif
 359 }
 360
 361 /* Scan the real Linux page tables and return a PTE pointer for
 362  * a virtual address in a context.
 363  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 364  * the PTE pointer is unmodified if PTE is not found.
 365  */
 366 int
 367 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 368 {
 369         pgd_t   *pgd;
 370         pud_t   *pud;
 371         pmd_t   *pmd;
 372         pte_t   *pte;
 373         int     retval = 0;
 374
 375         pgd = pgd_offset(mm, addr & PAGE_MASK);
 376         if (pgd) {
 377                 pud = pud_offset(pgd, addr & PAGE_MASK);
 378                 if (pud && pud_present(*pud)) {
 379                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 380                         if (pmd_present(*pmd)) {
 381                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 382                                 if (pte) {
 383                                         retval = 1;
 384                                         *ptep = pte;
 385                                         if (pmdp)
 386                                                 *pmdp = pmd;
 387                                         /* XXX caller needs to do pte_unmap, yuck */
 388                                 }
 389                         }
 390                 }
 391         }
 392         return(retval);
 393 }
 394
 395 #ifdef CONFIG_DEBUG_PAGEALLOC
 396
 397 static int __change_page_attr(struct page *page, pgprot_t prot)
 398 {
 399         pte_t *kpte;
 400         pmd_t *kpmd;
 401         unsigned long address;
 402
 403         BUG_ON(PageHighMem(page));
 404         address = (unsigned long)page_address(page);
 405
 406         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 407                 return 0;
 408         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 409                 return -EINVAL;
 410         __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
 411         wmb();
 412         flush_tlb_page(NULL, address);
 413         pte_unmap(kpte);
 414
 415         return 0;
 416 }
 417
 418 /*
 419  * Change the page attributes of an page in the linear mapping.
 420  *
 421  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 422  */
 423 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 424 {
 425         int i, err = 0;
 426         unsigned long flags;
 427
 428         local_irq_save(flags);
 429         for (i = 0; i < numpages; i++, page++) {
 430                 err = __change_page_attr(page, prot);
 431                 if (err)
 432                         break;
 433         }
 434         local_irq_restore(flags);
 435         return err;
 436 }
 437
 438
 439 void __kernel_map_pages(struct page *page, int numpages, int enable)
 440 {
 441         if (PageHighMem(page))
 442                 return;
 443
 444         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 445 }
 446 #endif /* CONFIG_DEBUG_PAGEALLOC */
 447
 448 static int fixmaps;
 449
 450 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 451 {
 452         unsigned long address = __fix_to_virt(idx);
 453
 454         if (idx >= __end_of_fixed_addresses) {
 455                 BUG();
 456                 return;
 457         }
 458
 459         map_page(address, phys, pgprot_val(flags));
 460         fixmaps++;
 461 }
 462
 463 void __this_fixmap_does_not_exist(void)
 464 {
 465         WARN_ON(1);
 466 }