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 CONFIG_SMP
  52 extern void hash_page_sync(void);
  53 #endif
  54
  55 #ifdef HAVE_BATS
  56 extern unsigned long v_mapped_by_bats(unsigned long va);
  57 extern unsigned long p_mapped_by_bats(unsigned long pa);
  58 void setbat(int index, unsigned long virt, unsigned long phys,
  59             unsigned int size, int flags);
  60
  61 #else /* !HAVE_BATS */
  62 #define v_mapped_by_bats(x)     (0UL)
  63 #define p_mapped_by_bats(x)     (0UL)
  64 #endif /* HAVE_BATS */
  65
  66 #ifdef HAVE_TLBCAM
  67 extern unsigned int tlbcam_index;
  68 extern unsigned long v_mapped_by_tlbcam(unsigned long va);
  69 extern unsigned long p_mapped_by_tlbcam(unsigned long pa);
  70 #else /* !HAVE_TLBCAM */
  71 #define v_mapped_by_tlbcam(x)   (0UL)
  72 #define p_mapped_by_tlbcam(x)   (0UL)
  73 #endif /* HAVE_TLBCAM */
  74
  75 #ifdef CONFIG_PTE_64BIT
  76 /* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
  77 #define PGDIR_ORDER     1
  78 #else
  79 #define PGDIR_ORDER     0
  80 #endif
  81
  82 pgd_t *pgd_alloc(struct mm_struct *mm)
  83 {
  84         pgd_t *ret;
  85
  86         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
  87         return ret;
  88 }
  89
  90 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  91 {
  92         free_pages((unsigned long)pgd, PGDIR_ORDER);
  93 }
  94
  95 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  96 {
  97         pte_t *pte;
  98         extern int mem_init_done;
  99         extern void *early_get_page(void);
 100
 101         if (mem_init_done) {
 102                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 103         } else {
 104                 pte = (pte_t *)early_get_page();
 105                 if (pte)
 106                         clear_page(pte);
 107         }
 108         return pte;
 109 }
 110
 111 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 112 {
 113         struct page *ptepage;
 114
 115 #ifdef CONFIG_HIGHPTE
 116         gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT | __GFP_ZERO;
 117 #else
 118         gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
 119 #endif
 120
 121         ptepage = alloc_pages(flags, 0);
 122         if (!ptepage)
 123                 return NULL;
 124         pgtable_page_ctor(ptepage);
 125         return ptepage;
 126 }
 127
 128 void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 129 {
 130 #ifdef CONFIG_SMP
 131         hash_page_sync();
 132 #endif
 133         free_page((unsigned long)pte);
 134 }
 135
 136 void pte_free(struct mm_struct *mm, pgtable_t ptepage)
 137 {
 138 #ifdef CONFIG_SMP
 139         hash_page_sync();
 140 #endif
 141         pgtable_page_dtor(ptepage);
 142         __free_page(ptepage);
 143 }
 144
 145 void __iomem *
 146 ioremap(phys_addr_t addr, unsigned long size)
 147 {
 148         return __ioremap(addr, size, _PAGE_NO_CACHE);
 149 }
 150 EXPORT_SYMBOL(ioremap);
 151
 152 void __iomem *
 153 ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
 154 {
 155         return __ioremap(addr, size, flags);
 156 }
 157 EXPORT_SYMBOL(ioremap_flags);
 158
 159 void __iomem *
 160 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 161 {
 162         unsigned long v, i;
 163         phys_addr_t p;
 164         int err;
 165
 166         /*
 167          * Choose an address to map it to.
 168          * Once the vmalloc system is running, we use it.
 169          * Before then, we use space going down from ioremap_base
 170          * (ioremap_bot records where we're up to).
 171          */
 172         p = addr & PAGE_MASK;
 173         size = PAGE_ALIGN(addr + size) - p;
 174
 175         /*
 176          * If the address lies within the first 16 MB, assume it's in ISA
 177          * memory space
 178          */
 179         if (p < 16*1024*1024)
 180                 p += _ISA_MEM_BASE;
 181
 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
 192         if (size == 0)
 193                 return NULL;
 194
 195         /*
 196          * Is it already mapped?  Perhaps overlapped by a previous
 197          * BAT mapping.  If the whole area is mapped then we're done,
 198          * otherwise remap it since we want to keep the virt addrs for
 199          * each request contiguous.
 200          *
 201          * We make the assumption here that if the bottom and top
 202          * of the range we want are mapped then it's mapped to the
 203          * same virt address (and this is contiguous).
 204          *  -- Cort
 205          */
 206         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 207                 goto out;
 208
 209         if ((v = p_mapped_by_tlbcam(p)))
 210                 goto out;
 211
 212         if (mem_init_done) {
 213                 struct vm_struct *area;
 214                 area = get_vm_area(size, VM_IOREMAP);
 215                 if (area == 0)
 216                         return NULL;
 217                 v = (unsigned long) area->addr;
 218         } else {
 219                 v = (ioremap_bot -= size);
 220         }
 221
 222         if ((flags & _PAGE_PRESENT) == 0)
 223                 flags |= _PAGE_KERNEL;
 224         if (flags & _PAGE_NO_CACHE)
 225                 flags |= _PAGE_GUARDED;
 226
 227         /*
 228          * Should check if it is a candidate for a BAT mapping
 229          */
 230
 231         err = 0;
 232         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 233                 err = map_page(v+i, p+i, flags);
 234         if (err) {
 235                 if (mem_init_done)
 236                         vunmap((void *)v);
 237                 return NULL;
 238         }
 239
 240 out:
 241         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 242 }
 243 EXPORT_SYMBOL(__ioremap);
 244
 245 void iounmap(volatile void __iomem *addr)
 246 {
 247         /*
 248          * If mapped by BATs then there is nothing to do.
 249          * Calling vfree() generates a benign warning.
 250          */
 251         if (v_mapped_by_bats((unsigned long)addr)) return;
 252
 253         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 254                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 255 }
 256 EXPORT_SYMBOL(iounmap);
 257
 258 int map_page(unsigned long va, phys_addr_t pa, int flags)
 259 {
 260         pmd_t *pd;
 261         pte_t *pg;
 262         int err = -ENOMEM;
 263
 264         /* Use upper 10 bits of VA to index the first level map */
 265         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 266         /* Use middle 10 bits of VA to index the second-level map */
 267         pg = pte_alloc_kernel(pd, va);
 268         if (pg != 0) {
 269                 err = 0;
 270                 /* The PTE should never be already set nor present in the
 271                  * hash table
 272                  */
 273                 BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
 274                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 275                                                      __pgprot(flags)));
 276         }
 277         return err;
 278 }
 279
 280 /*
 281  * Map in all of physical memory starting at KERNELBASE.
 282  */
 283 void __init mapin_ram(void)
 284 {
 285         unsigned long v, s, f;
 286         phys_addr_t p;
 287         int ktext;
 288
 289         s = mmu_mapin_ram();
 290         v = KERNELBASE + s;
 291         p = memstart_addr + s;
 292         for (; s < total_lowmem; s += PAGE_SIZE) {
 293                 ktext = ((char *) v >= _stext && (char *) v < etext);
 294                 f = ktext ?_PAGE_RAM_TEXT : _PAGE_RAM;
 295                 map_page(v, p, f);
 296 #ifdef CONFIG_PPC_STD_MMU_32
 297                 if (ktext)
 298                         hash_preload(&init_mm, v, 0, 0x300);
 299 #endif
 300                 v += PAGE_SIZE;
 301                 p += PAGE_SIZE;
 302         }
 303 }
 304
 305 /* Scan the real Linux page tables and return a PTE pointer for
 306  * a virtual address in a context.
 307  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 308  * the PTE pointer is unmodified if PTE is not found.
 309  */
 310 int
 311 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 312 {
 313         pgd_t   *pgd;
 314         pud_t   *pud;
 315         pmd_t   *pmd;
 316         pte_t   *pte;
 317         int     retval = 0;
 318
 319         pgd = pgd_offset(mm, addr & PAGE_MASK);
 320         if (pgd) {
 321                 pud = pud_offset(pgd, addr & PAGE_MASK);
 322                 if (pud && pud_present(*pud)) {
 323                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 324                         if (pmd_present(*pmd)) {
 325                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 326                                 if (pte) {
 327                                         retval = 1;
 328                                         *ptep = pte;
 329                                         if (pmdp)
 330                                                 *pmdp = pmd;
 331                                         /* XXX caller needs to do pte_unmap, yuck */
 332                                 }
 333                         }
 334                 }
 335         }
 336         return(retval);
 337 }
 338
 339 #ifdef CONFIG_DEBUG_PAGEALLOC
 340
 341 static int __change_page_attr(struct page *page, pgprot_t prot)
 342 {
 343         pte_t *kpte;
 344         pmd_t *kpmd;
 345         unsigned long address;
 346
 347         BUG_ON(PageHighMem(page));
 348         address = (unsigned long)page_address(page);
 349
 350         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 351                 return 0;
 352         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 353                 return -EINVAL;
 354         set_pte_at(&init_mm, address, kpte, mk_pte(page, prot));
 355         wmb();
 356         flush_HPTE(0, address, pmd_val(*kpmd));
 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 = 0xfffff000;
 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, flags);
 406         fixmaps++;
 407 }
 408
 409 void __this_fixmap_does_not_exist(void)
 410 {
 411         WARN_ON(1);
 412 }