arch/ppc/mm/pgtable.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  *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
  12  *
  13  *  Derived from "arch/i386/mm/init.c"
  14  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  15  *
  16  *  This program is free software; you can redistribute it and/or
  17  *  modify it under the terms of the GNU General Public License
  18  *  as published by the Free Software Foundation; either version
  19  *  2 of the License, or (at your option) any later version.
  20  *
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/types.h>
  26 #include <linux/mm.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/init.h>
  29 #include <linux/highmem.h>
  30
  31 #include <asm/pgtable.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/io.h>
  34
  35 #include "mmu_decl.h"
  36
  37 unsigned long ioremap_base;
  38 unsigned long ioremap_bot;
  39 int io_bat_index;
  40
  41 #if defined(CONFIG_6xx)
  42 #define HAVE_BATS       1
  43 #endif
  44
  45 extern char etext[], _stext[];
  46
  47 #ifdef CONFIG_SMP
  48 extern void hash_page_sync(void);
  49 #endif
  50
  51 #ifdef HAVE_BATS
  52 extern unsigned long v_mapped_by_bats(unsigned long va);
  53 extern unsigned long p_mapped_by_bats(unsigned long pa);
  54 void setbat(int index, unsigned long virt, unsigned long 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 CONFIG_PTE_64BIT
  63 /* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
  64 #define PGDIR_ORDER     1
  65 #else
  66 #define PGDIR_ORDER     0
  67 #endif
  68
  69 pgd_t *pgd_alloc(struct mm_struct *mm)
  70 {
  71         pgd_t *ret;
  72
  73         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
  74         return ret;
  75 }
  76
  77 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  78 {
  79         free_pages((unsigned long)pgd, PGDIR_ORDER);
  80 }
  81
  82 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  83 {
  84         pte_t *pte;
  85         extern int mem_init_done;
  86         extern void *early_get_page(void);
  87
  88         if (mem_init_done) {
  89                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
  90         } else {
  91                 pte = (pte_t *)early_get_page();
  92                 if (pte)
  93                         clear_page(pte);
  94         }
  95         return pte;
  96 }
  97
  98 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
  99 {
 100         struct page *ptepage;
 101
 102 #ifdef CONFIG_HIGHPTE
 103         gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
 104 #else
 105         gfp_t flags = GFP_KERNEL | __GFP_REPEAT;
 106 #endif
 107
 108         ptepage = alloc_pages(flags, 0);
 109         if (ptepage)
 110                 clear_highpage(ptepage);
 111         return ptepage;
 112 }
 113
 114 void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 115 {
 116 #ifdef CONFIG_SMP
 117         hash_page_sync();
 118 #endif
 119         free_page((unsigned long)pte);
 120 }
 121
 122 void pte_free(struct mm_struct *mm, struct page *ptepage)
 123 {
 124 #ifdef CONFIG_SMP
 125         hash_page_sync();
 126 #endif
 127         __free_page(ptepage);
 128 }
 129
 130 #ifndef CONFIG_PHYS_64BIT
 131 void __iomem *
 132 ioremap(phys_addr_t addr, unsigned long size)
 133 {
 134         return __ioremap(addr, size, _PAGE_NO_CACHE);
 135 }
 136 #else /* CONFIG_PHYS_64BIT */
 137 void __iomem *
 138 ioremap64(unsigned long long addr, unsigned long size)
 139 {
 140         return __ioremap(addr, size, _PAGE_NO_CACHE);
 141 }
 142
 143 void __iomem *
 144 ioremap(phys_addr_t addr, unsigned long size)
 145 {
 146         phys_addr_t addr64 = fixup_bigphys_addr(addr, size);
 147
 148         return ioremap64(addr64, size);
 149 }
 150 #endif /* CONFIG_PHYS_64BIT */
 151
 152 void __iomem *
 153 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 154 {
 155         unsigned long v, i;
 156         phys_addr_t p;
 157         int err;
 158
 159         /*
 160          * Choose an address to map it to.
 161          * Once the vmalloc system is running, we use it.
 162          * Before then, we use space going down from ioremap_base
 163          * (ioremap_bot records where we're up to).
 164          */
 165         p = addr & PAGE_MASK;
 166         size = PAGE_ALIGN(addr + size) - p;
 167
 168         /*
 169          * If the address lies within the first 16 MB, assume it's in ISA
 170          * memory space
 171          */
 172         if (p < 16*1024*1024)
 173                 p += _ISA_MEM_BASE;
 174
 175         /*
 176          * Don't allow anybody to remap normal RAM that we're using.
 177          * mem_init() sets high_memory so only do the check after that.
 178          */
 179         if ( mem_init_done && (p < virt_to_phys(high_memory)) )
 180         {
 181                 printk("__ioremap(): phys addr "PHYS_FMT" is RAM lr %p\n", p,
 182                        __builtin_return_address(0));
 183                 return NULL;
 184         }
 185
 186         if (size == 0)
 187                 return NULL;
 188
 189         /*
 190          * Is it already mapped?  Perhaps overlapped by a previous
 191          * BAT mapping.  If the whole area is mapped then we're done,
 192          * otherwise remap it since we want to keep the virt addrs for
 193          * each request contiguous.
 194          *
 195          * We make the assumption here that if the bottom and top
 196          * of the range we want are mapped then it's mapped to the
 197          * same virt address (and this is contiguous).
 198          *  -- Cort
 199          */
 200         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 201                 goto out;
 202
 203         if (mem_init_done) {
 204                 struct vm_struct *area;
 205                 area = get_vm_area(size, VM_IOREMAP);
 206                 if (area == 0)
 207                         return NULL;
 208                 v = (unsigned long) area->addr;
 209         } else {
 210                 v = (ioremap_bot -= size);
 211         }
 212
 213         if ((flags & _PAGE_PRESENT) == 0)
 214                 flags |= _PAGE_KERNEL;
 215         if (flags & _PAGE_NO_CACHE)
 216                 flags |= _PAGE_GUARDED;
 217
 218         /*
 219          * Should check if it is a candidate for a BAT mapping
 220          */
 221
 222         err = 0;
 223         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 224                 err = map_page(v+i, p+i, flags);
 225         if (err) {
 226                 if (mem_init_done)
 227                         vunmap((void *)v);
 228                 return NULL;
 229         }
 230
 231 out:
 232         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 233 }
 234
 235 void iounmap(volatile void __iomem *addr)
 236 {
 237         /*
 238          * If mapped by BATs then there is nothing to do.
 239          * Calling vfree() generates a benign warning.
 240          */
 241         if (v_mapped_by_bats((unsigned long)addr)) return;
 242
 243         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 244                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 245 }
 246
 247 void __iomem *ioport_map(unsigned long port, unsigned int len)
 248 {
 249         return (void __iomem *) (port + _IO_BASE);
 250 }
 251
 252 void ioport_unmap(void __iomem *addr)
 253 {
 254         /* Nothing to do */
 255 }
 256 EXPORT_SYMBOL(ioport_map);
 257 EXPORT_SYMBOL(ioport_unmap);
 258
 259 int
 260 map_page(unsigned long va, phys_addr_t pa, int flags)
 261 {
 262         pmd_t *pd;
 263         pte_t *pg;
 264         int err = -ENOMEM;
 265
 266         /* Use upper 10 bits of VA to index the first level map */
 267         pd = pmd_offset(pgd_offset_k(va), va);
 268         /* Use middle 10 bits of VA to index the second-level map */
 269         pg = pte_alloc_kernel(pd, va);
 270         if (pg != 0) {
 271                 err = 0;
 272                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
 273                 if (mem_init_done)
 274                         flush_HPTE(0, va, pmd_val(*pd));
 275         }
 276         return err;
 277 }
 278
 279 /*
 280  * Map in all of physical memory starting at KERNELBASE.
 281  */
 282 void __init mapin_ram(void)
 283 {
 284         unsigned long v, p, s, f;
 285
 286         s = mmu_mapin_ram();
 287         v = KERNELBASE + s;
 288         p = PPC_MEMSTART + s;
 289         for (; s < total_lowmem; s += PAGE_SIZE) {
 290                 if ((char *) v >= _stext && (char *) v < etext)
 291                         f = _PAGE_RAM_TEXT;
 292                 else
 293                         f = _PAGE_RAM;
 294                 map_page(v, p, f);
 295                 v += PAGE_SIZE;
 296                 p += PAGE_SIZE;
 297         }
 298 }
 299
 300 /* is x a power of 4? */
 301 #define is_power_of_4(x)        is_power_of_2(x) && (ffs(x) & 1)
 302
 303 /*
 304  * Set up a mapping for a block of I/O.
 305  * virt, phys, size must all be page-aligned.
 306  * This should only be called before ioremap is called.
 307  */
 308 void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
 309                              unsigned int size, int flags)
 310 {
 311         int i;
 312
 313         if (virt > KERNELBASE && virt < ioremap_bot)
 314                 ioremap_bot = ioremap_base = virt;
 315
 316 #ifdef HAVE_BATS
 317         /*
 318          * Use a BAT for this if possible...
 319          */
 320         if (io_bat_index < 2 && is_power_of_2(size)
 321             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 322                 setbat(io_bat_index, virt, phys, size, flags);
 323                 ++io_bat_index;
 324                 return;
 325         }
 326 #endif /* HAVE_BATS */
 327
 328         /* No BATs available, put it in the page tables. */
 329         for (i = 0; i < size; i += PAGE_SIZE)
 330                 map_page(virt + i, phys + i, flags);
 331 }
 332
 333 /* Scan the real Linux page tables and return a PTE pointer for
 334  * a virtual address in a context.
 335  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 336  * the PTE pointer is unmodified if PTE is not found.
 337  */
 338 int
 339 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 340 {
 341         pgd_t   *pgd;
 342         pmd_t   *pmd;
 343         pte_t   *pte;
 344         int     retval = 0;
 345
 346         pgd = pgd_offset(mm, addr & PAGE_MASK);
 347         if (pgd) {
 348                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 349                 if (pmd_present(*pmd)) {
 350                         pte = pte_offset_map(pmd, addr & PAGE_MASK);
 351                         if (pte) {
 352                                 retval = 1;
 353                                 *ptep = pte;
 354                                 if (pmdp)
 355                                         *pmdp = pmd;
 356                                 /* XXX caller needs to do pte_unmap, yuck */
 357                         }
 358                 }
 359         }
 360         return(retval);
 361 }
 362
 363 /* Find physical address for this virtual address.  Normally used by
 364  * I/O functions, but anyone can call it.
 365  */
 366 unsigned long iopa(unsigned long addr)
 367 {
 368         unsigned long pa;
 369
 370         /* I don't know why this won't work on PMacs or CHRP.  It
 371          * appears there is some bug, or there is some implicit
 372          * mapping done not properly represented by BATs or in page
 373          * tables.......I am actively working on resolving this, but
 374          * can't hold up other stuff.  -- Dan
 375          */
 376         pte_t *pte;
 377         struct mm_struct *mm;
 378
 379         /* Check the BATs */
 380         pa = v_mapped_by_bats(addr);
 381         if (pa)
 382                 return pa;
 383
 384         /* Allow mapping of user addresses (within the thread)
 385          * for DMA if necessary.
 386          */
 387         if (addr < TASK_SIZE)
 388                 mm = current->mm;
 389         else
 390                 mm = &init_mm;
 391
 392         pa = 0;
 393         if (get_pteptr(mm, addr, &pte, NULL)) {
 394                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 395                 pte_unmap(pte);
 396         }
 397
 398         return(pa);
 399 }
 400