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/config.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/types.h>
  27 #include <linux/mm.h>
  28 #include <linux/vmalloc.h>
  29 #include <linux/init.h>
  30 #include <linux/highmem.h>
  31
  32 #include <asm/pgtable.h>
  33 #include <asm/pgalloc.h>
  34 #include <asm/io.h>
  35
  36 #include "mmu_decl.h"
  37
  38 unsigned long ioremap_base;
  39 unsigned long ioremap_bot;
  40 int io_bat_index;
  41
  42 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
  43 #define HAVE_BATS       1
  44 #endif
  45
  46 #if defined(CONFIG_FSL_BOOKE)
  47 #define HAVE_TLBCAM     1
  48 #endif
  49
  50 extern char etext[], _stext[];
  51
  52 #ifdef CONFIG_SMP
  53 extern void hash_page_sync(void);
  54 #endif
  55
  56 #ifdef HAVE_BATS
  57 extern unsigned long v_mapped_by_bats(unsigned long va);
  58 extern unsigned long p_mapped_by_bats(unsigned long pa);
  59 void setbat(int index, unsigned long virt, unsigned long phys,
  60             unsigned int size, int flags);
  61
  62 #else /* !HAVE_BATS */
  63 #define v_mapped_by_bats(x)     (0UL)
  64 #define p_mapped_by_bats(x)     (0UL)
  65 #endif /* HAVE_BATS */
  66
  67 #ifdef HAVE_TLBCAM
  68 extern unsigned int tlbcam_index;
  69 extern unsigned long v_mapped_by_tlbcam(unsigned long va);
  70 extern unsigned long p_mapped_by_tlbcam(unsigned long pa);
  71 #else /* !HAVE_TLBCAM */
  72 #define v_mapped_by_tlbcam(x)   (0UL)
  73 #define p_mapped_by_tlbcam(x)   (0UL)
  74 #endif /* HAVE_TLBCAM */
  75
  76 #ifdef CONFIG_PTE_64BIT
  77 /* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
  78 #define PGDIR_ORDER     1
  79 #else
  80 #define PGDIR_ORDER     0
  81 #endif
  82
  83 pgd_t *pgd_alloc(struct mm_struct *mm)
  84 {
  85         pgd_t *ret;
  86
  87         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
  88         return ret;
  89 }
  90
  91 void pgd_free(pgd_t *pgd)
  92 {
  93         free_pages((unsigned long)pgd, PGDIR_ORDER);
  94 }
  95
  96 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  97 {
  98         pte_t *pte;
  99         extern int mem_init_done;
 100         extern void *early_get_page(void);
 101
 102         if (mem_init_done) {
 103                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 104         } else {
 105                 pte = (pte_t *)early_get_page();
 106                 if (pte)
 107                         clear_page(pte);
 108         }
 109         return pte;
 110 }
 111
 112 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 113 {
 114         struct page *ptepage;
 115
 116 #ifdef CONFIG_HIGHPTE
 117         int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
 118 #else
 119         int flags = GFP_KERNEL | __GFP_REPEAT;
 120 #endif
 121
 122         ptepage = alloc_pages(flags, 0);
 123         if (ptepage)
 124                 clear_highpage(ptepage);
 125         return ptepage;
 126 }
 127
 128 void pte_free_kernel(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 page *ptepage)
 137 {
 138 #ifdef CONFIG_SMP
 139         hash_page_sync();
 140 #endif
 141         __free_page(ptepage);
 142 }
 143
 144 #ifndef CONFIG_PHYS_64BIT
 145 void __iomem *
 146 ioremap(phys_addr_t addr, unsigned long size)
 147 {
 148         return __ioremap(addr, size, _PAGE_NO_CACHE);
 149 }
 150 #else /* CONFIG_PHYS_64BIT */
 151 void __iomem *
 152 ioremap64(unsigned long long addr, unsigned long size)
 153 {
 154         return __ioremap(addr, size, _PAGE_NO_CACHE);
 155 }
 156
 157 void __iomem *
 158 ioremap(phys_addr_t addr, unsigned long size)
 159 {
 160         phys_addr_t addr64 = fixup_bigphys_addr(addr, size);
 161
 162         return ioremap64(addr64, size);
 163 }
 164 #endif /* CONFIG_PHYS_64BIT */
 165
 166 void __iomem *
 167 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 168 {
 169         unsigned long v, i;
 170         phys_addr_t p;
 171         int err;
 172
 173         /*
 174          * Choose an address to map it to.
 175          * Once the vmalloc system is running, we use it.
 176          * Before then, we use space going down from ioremap_base
 177          * (ioremap_bot records where we're up to).
 178          */
 179         p = addr & PAGE_MASK;
 180         size = PAGE_ALIGN(addr + size) - p;
 181
 182         /*
 183          * If the address lies within the first 16 MB, assume it's in ISA
 184          * memory space
 185          */
 186         if (p < 16*1024*1024)
 187                 p += _ISA_MEM_BASE;
 188
 189         /*
 190          * Don't allow anybody to remap normal RAM that we're using.
 191          * mem_init() sets high_memory so only do the check after that.
 192          */
 193         if ( mem_init_done && (p < virt_to_phys(high_memory)) )
 194         {
 195                 printk("__ioremap(): phys addr "PHYS_FMT" is RAM lr %p\n", p,
 196                        __builtin_return_address(0));
 197                 return NULL;
 198         }
 199
 200         if (size == 0)
 201                 return NULL;
 202
 203         /*
 204          * Is it already mapped?  Perhaps overlapped by a previous
 205          * BAT mapping.  If the whole area is mapped then we're done,
 206          * otherwise remap it since we want to keep the virt addrs for
 207          * each request contiguous.
 208          *
 209          * We make the assumption here that if the bottom and top
 210          * of the range we want are mapped then it's mapped to the
 211          * same virt address (and this is contiguous).
 212          *  -- Cort
 213          */
 214         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 215                 goto out;
 216
 217         if ((v = p_mapped_by_tlbcam(p)))
 218                 goto out;
 219
 220         if (mem_init_done) {
 221                 struct vm_struct *area;
 222                 area = get_vm_area(size, VM_IOREMAP);
 223                 if (area == 0)
 224                         return NULL;
 225                 v = (unsigned long) area->addr;
 226         } else {
 227                 v = (ioremap_bot -= size);
 228         }
 229
 230         if ((flags & _PAGE_PRESENT) == 0)
 231                 flags |= _PAGE_KERNEL;
 232         if (flags & _PAGE_NO_CACHE)
 233                 flags |= _PAGE_GUARDED;
 234
 235         /*
 236          * Should check if it is a candidate for a BAT mapping
 237          */
 238
 239         err = 0;
 240         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 241                 err = map_page(v+i, p+i, flags);
 242         if (err) {
 243                 if (mem_init_done)
 244                         vunmap((void *)v);
 245                 return NULL;
 246         }
 247
 248 out:
 249         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 250 }
 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
 264 void __iomem *ioport_map(unsigned long port, unsigned int len)
 265 {
 266         return (void __iomem *) (port + _IO_BASE);
 267 }
 268
 269 void ioport_unmap(void __iomem *addr)
 270 {
 271         /* Nothing to do */
 272 }
 273 EXPORT_SYMBOL(ioport_map);
 274 EXPORT_SYMBOL(ioport_unmap);
 275
 276 int
 277 map_page(unsigned long va, phys_addr_t pa, int flags)
 278 {
 279         pmd_t *pd;
 280         pte_t *pg;
 281         int err = -ENOMEM;
 282
 283         spin_lock(&init_mm.page_table_lock);
 284         /* Use upper 10 bits of VA to index the first level map */
 285         pd = pmd_offset(pgd_offset_k(va), va);
 286         /* Use middle 10 bits of VA to index the second-level map */
 287         pg = pte_alloc_kernel(&init_mm, pd, va);
 288         if (pg != 0) {
 289                 err = 0;
 290                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
 291                 if (mem_init_done)
 292                         flush_HPTE(0, va, pmd_val(*pd));
 293         }
 294         spin_unlock(&init_mm.page_table_lock);
 295         return err;
 296 }
 297
 298 /*
 299  * Map in all of physical memory starting at KERNELBASE.
 300  */
 301 void __init mapin_ram(void)
 302 {
 303         unsigned long v, p, s, f;
 304
 305         s = mmu_mapin_ram();
 306         v = KERNELBASE + s;
 307         p = PPC_MEMSTART + s;
 308         for (; s < total_lowmem; s += PAGE_SIZE) {
 309                 if ((char *) v >= _stext && (char *) v < etext)
 310                         f = _PAGE_RAM_TEXT;
 311                 else
 312                         f = _PAGE_RAM;
 313                 map_page(v, p, f);
 314                 v += PAGE_SIZE;
 315                 p += PAGE_SIZE;
 316         }
 317 }
 318
 319 /* is x a power of 2? */
 320 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 321
 322 /* is x a power of 4? */
 323 #define is_power_of_4(x)        ((x) != 0 && (((x) & (x-1)) == 0) && (ffs(x) & 1))
 324
 325 /*
 326  * Set up a mapping for a block of I/O.
 327  * virt, phys, size must all be page-aligned.
 328  * This should only be called before ioremap is called.
 329  */
 330 void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
 331                              unsigned int size, int flags)
 332 {
 333         int i;
 334
 335         if (virt > KERNELBASE && virt < ioremap_bot)
 336                 ioremap_bot = ioremap_base = virt;
 337
 338 #ifdef HAVE_BATS
 339         /*
 340          * Use a BAT for this if possible...
 341          */
 342         if (io_bat_index < 2 && is_power_of_2(size)
 343             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 344                 setbat(io_bat_index, virt, phys, size, flags);
 345                 ++io_bat_index;
 346                 return;
 347         }
 348 #endif /* HAVE_BATS */
 349
 350 #ifdef HAVE_TLBCAM
 351         /*
 352          * Use a CAM for this if possible...
 353          */
 354         if (tlbcam_index < num_tlbcam_entries && is_power_of_4(size)
 355             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 356                 settlbcam(tlbcam_index, virt, phys, size, flags, 0);
 357                 ++tlbcam_index;
 358                 return;
 359         }
 360 #endif /* HAVE_TLBCAM */
 361
 362         /* No BATs available, put it in the page tables. */
 363         for (i = 0; i < size; i += PAGE_SIZE)
 364                 map_page(virt + i, phys + i, flags);
 365 }
 366
 367 /* Scan the real Linux page tables and return a PTE pointer for
 368  * a virtual address in a context.
 369  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 370  * the PTE pointer is unmodified if PTE is not found.
 371  */
 372 int
 373 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
 374 {
 375         pgd_t   *pgd;
 376         pmd_t   *pmd;
 377         pte_t   *pte;
 378         int     retval = 0;
 379
 380         pgd = pgd_offset(mm, addr & PAGE_MASK);
 381         if (pgd) {
 382                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 383                 if (pmd_present(*pmd)) {
 384                         pte = pte_offset_map(pmd, addr & PAGE_MASK);
 385                         if (pte) {
 386                                 retval = 1;
 387                                 *ptep = pte;
 388                                 /* XXX caller needs to do pte_unmap, yuck */
 389                         }
 390                 }
 391         }
 392         return(retval);
 393 }
 394
 395 /* Find physical address for this virtual address.  Normally used by
 396  * I/O functions, but anyone can call it.
 397  */
 398 unsigned long iopa(unsigned long addr)
 399 {
 400         unsigned long pa;
 401
 402         /* I don't know why this won't work on PMacs or CHRP.  It
 403          * appears there is some bug, or there is some implicit
 404          * mapping done not properly represented by BATs or in page
 405          * tables.......I am actively working on resolving this, but
 406          * can't hold up other stuff.  -- Dan
 407          */
 408         pte_t *pte;
 409         struct mm_struct *mm;
 410
 411         /* Check the BATs */
 412         pa = v_mapped_by_bats(addr);
 413         if (pa)
 414                 return pa;
 415
 416         /* Allow mapping of user addresses (within the thread)
 417          * for DMA if necessary.
 418          */
 419         if (addr < TASK_SIZE)
 420                 mm = current->mm;
 421         else
 422                 mm = &init_mm;
 423
 424         pa = 0;
 425         if (get_pteptr(mm, addr, &pte)) {
 426                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 427                 pte_unmap(pte);
 428         }
 429
 430         return(pa);
 431 }
 432
 433 /* This is will find the virtual address for a physical one....
 434  * Swiped from APUS, could be dangerous :-).
 435  * This is only a placeholder until I really find a way to make this
 436  * work.  -- Dan
 437  */
 438 unsigned long
 439 mm_ptov (unsigned long paddr)
 440 {
 441         unsigned long ret;
 442 #if 0
 443         if (paddr < 16*1024*1024)
 444                 ret = ZTWO_VADDR(paddr);
 445         else {
 446                 int i;
 447
 448                 for (i = 0; i < kmap_chunk_count;){
 449                         unsigned long phys = kmap_chunks[i++];
 450                         unsigned long size = kmap_chunks[i++];
 451                         unsigned long virt = kmap_chunks[i++];
 452                         if (paddr >= phys
 453                             && paddr < (phys + size)){
 454                                 ret = virt + paddr - phys;
 455                                 goto exit;
 456                         }
 457                 }
 458
 459                 ret = (unsigned long) __va(paddr);
 460         }
 461 exit:
 462 #ifdef DEBUGPV
 463         printk ("PTOV(%lx)=%lx\n", paddr, ret);
 464 #endif
 465 #else
 466         ret = (unsigned long)paddr + KERNELBASE;
 467 #endif
 468         return ret;
 469 }
 470