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/io.h>
  33
  34 #include "mmu_decl.h"
  35
  36 unsigned long ioremap_base;
  37 unsigned long ioremap_bot;
  38 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
  39
  40 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
  41 #define HAVE_BATS       1
  42 #endif
  43
  44 #if defined(CONFIG_FSL_BOOKE)
  45 #define HAVE_TLBCAM     1
  46 #endif
  47
  48 extern char etext[], _stext[];
  49
  50 #ifdef CONFIG_SMP
  51 extern void hash_page_sync(void);
  52 #endif
  53
  54 #ifdef HAVE_BATS
  55 extern unsigned long v_mapped_by_bats(unsigned long va);
  56 extern unsigned long p_mapped_by_bats(unsigned long pa);
  57 void setbat(int index, unsigned long virt, unsigned long phys,
  58             unsigned int size, int flags);
  59
  60 #else /* !HAVE_BATS */
  61 #define v_mapped_by_bats(x)     (0UL)
  62 #define p_mapped_by_bats(x)     (0UL)
  63 #endif /* HAVE_BATS */
  64
  65 #ifdef HAVE_TLBCAM
  66 extern unsigned int tlbcam_index;
  67 extern unsigned long v_mapped_by_tlbcam(unsigned long va);
  68 extern unsigned long p_mapped_by_tlbcam(unsigned long pa);
  69 #else /* !HAVE_TLBCAM */
  70 #define v_mapped_by_tlbcam(x)   (0UL)
  71 #define p_mapped_by_tlbcam(x)   (0UL)
  72 #endif /* HAVE_TLBCAM */
  73
  74 #ifdef CONFIG_PTE_64BIT
  75 /* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
  76 #define PGDIR_ORDER     1
  77 #else
  78 #define PGDIR_ORDER     0
  79 #endif
  80
  81 pgd_t *pgd_alloc(struct mm_struct *mm)
  82 {
  83         pgd_t *ret;
  84
  85         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
  86         return ret;
  87 }
  88
  89 void pgd_free(pgd_t *pgd)
  90 {
  91         free_pages((unsigned long)pgd, PGDIR_ORDER);
  92 }
  93
  94 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  95 {
  96         pte_t *pte;
  97         extern int mem_init_done;
  98         extern void *early_get_page(void);
  99
 100         if (mem_init_done) {
 101                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 102         } else {
 103                 pte = (pte_t *)early_get_page();
 104                 if (pte)
 105                         clear_page(pte);
 106         }
 107         return pte;
 108 }
 109
 110 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 111 {
 112         struct page *ptepage;
 113
 114 #ifdef CONFIG_HIGHPTE
 115         gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
 116 #else
 117         gfp_t flags = GFP_KERNEL | __GFP_REPEAT;
 118 #endif
 119
 120         ptepage = alloc_pages(flags, 0);
 121         if (ptepage)
 122                 clear_highpage(ptepage);
 123         return ptepage;
 124 }
 125
 126 void pte_free_kernel(pte_t *pte)
 127 {
 128 #ifdef CONFIG_SMP
 129         hash_page_sync();
 130 #endif
 131         free_page((unsigned long)pte);
 132 }
 133
 134 void pte_free(struct page *ptepage)
 135 {
 136 #ifdef CONFIG_SMP
 137         hash_page_sync();
 138 #endif
 139         __free_page(ptepage);
 140 }
 141
 142 void __iomem *
 143 ioremap(phys_addr_t addr, unsigned long size)
 144 {
 145         return __ioremap(addr, size, _PAGE_NO_CACHE);
 146 }
 147 EXPORT_SYMBOL(ioremap);
 148
 149 void __iomem *
 150 ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
 151 {
 152         return __ioremap(addr, size, flags);
 153 }
 154 EXPORT_SYMBOL(ioremap_flags);
 155
 156 void __iomem *
 157 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 158 {
 159         unsigned long v, i;
 160         phys_addr_t p;
 161         int err;
 162
 163         /*
 164          * Choose an address to map it to.
 165          * Once the vmalloc system is running, we use it.
 166          * Before then, we use space going down from ioremap_base
 167          * (ioremap_bot records where we're up to).
 168          */
 169         p = addr & PAGE_MASK;
 170         size = PAGE_ALIGN(addr + size) - p;
 171
 172         /*
 173          * If the address lies within the first 16 MB, assume it's in ISA
 174          * memory space
 175          */
 176         if (p < 16*1024*1024)
 177                 p += _ISA_MEM_BASE;
 178
 179         /*
 180          * Don't allow anybody to remap normal RAM that we're using.
 181          * mem_init() sets high_memory so only do the check after that.
 182          */
 183         if (mem_init_done && (p < virt_to_phys(high_memory))) {
 184                 printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
 185                        (unsigned long long)p, __builtin_return_address(0));
 186                 return NULL;
 187         }
 188
 189         if (size == 0)
 190                 return NULL;
 191
 192         /*
 193          * Is it already mapped?  Perhaps overlapped by a previous
 194          * BAT mapping.  If the whole area is mapped then we're done,
 195          * otherwise remap it since we want to keep the virt addrs for
 196          * each request contiguous.
 197          *
 198          * We make the assumption here that if the bottom and top
 199          * of the range we want are mapped then it's mapped to the
 200          * same virt address (and this is contiguous).
 201          *  -- Cort
 202          */
 203         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 204                 goto out;
 205
 206         if ((v = p_mapped_by_tlbcam(p)))
 207                 goto out;
 208
 209         if (mem_init_done) {
 210                 struct vm_struct *area;
 211                 area = get_vm_area(size, VM_IOREMAP);
 212                 if (area == 0)
 213                         return NULL;
 214                 v = (unsigned long) area->addr;
 215         } else {
 216                 v = (ioremap_bot -= size);
 217         }
 218
 219         if ((flags & _PAGE_PRESENT) == 0)
 220                 flags |= _PAGE_KERNEL;
 221         if (flags & _PAGE_NO_CACHE)
 222                 flags |= _PAGE_GUARDED;
 223
 224         /*
 225          * Should check if it is a candidate for a BAT mapping
 226          */
 227
 228         err = 0;
 229         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 230                 err = map_page(v+i, p+i, flags);
 231         if (err) {
 232                 if (mem_init_done)
 233                         vunmap((void *)v);
 234                 return NULL;
 235         }
 236
 237 out:
 238         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 239 }
 240 EXPORT_SYMBOL(__ioremap);
 241
 242 void iounmap(volatile void __iomem *addr)
 243 {
 244         /*
 245          * If mapped by BATs then there is nothing to do.
 246          * Calling vfree() generates a benign warning.
 247          */
 248         if (v_mapped_by_bats((unsigned long)addr)) return;
 249
 250         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 251                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 252 }
 253 EXPORT_SYMBOL(iounmap);
 254
 255 int map_page(unsigned long va, phys_addr_t pa, int flags)
 256 {
 257         pmd_t *pd;
 258         pte_t *pg;
 259         int err = -ENOMEM;
 260
 261         /* Use upper 10 bits of VA to index the first level map */
 262         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 263         /* Use middle 10 bits of VA to index the second-level map */
 264         pg = pte_alloc_kernel(pd, va);
 265         if (pg != 0) {
 266                 err = 0;
 267                 /* The PTE should never be already set nor present in the
 268                  * hash table
 269                  */
 270                 BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
 271                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 272                                                      __pgprot(flags)));
 273         }
 274         return err;
 275 }
 276
 277 /*
 278  * Map in all of physical memory starting at KERNELBASE.
 279  */
 280 void __init mapin_ram(void)
 281 {
 282         unsigned long v, p, s, f;
 283         int ktext;
 284
 285         s = mmu_mapin_ram();
 286         v = KERNELBASE + s;
 287         p = PPC_MEMSTART + 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         flush_HPTE(0, address, pmd_val(*kpmd));
 353         pte_unmap(kpte);
 354
 355         return 0;
 356 }
 357
 358 /*
 359  * Change the page attributes of an page in the linear mapping.
 360  *
 361  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 362  */
 363 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 364 {
 365         int i, err = 0;
 366         unsigned long flags;
 367
 368         local_irq_save(flags);
 369         for (i = 0; i < numpages; i++, page++) {
 370                 err = __change_page_attr(page, prot);
 371                 if (err)
 372                         break;
 373         }
 374         local_irq_restore(flags);
 375         return err;
 376 }
 377
 378
 379 void kernel_map_pages(struct page *page, int numpages, int enable)
 380 {
 381         if (PageHighMem(page))
 382                 return;
 383
 384         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 385 }
 386 #endif /* CONFIG_DEBUG_PAGEALLOC */