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 int num_tlbcam_entries;
  70 extern unsigned long v_mapped_by_tlbcam(unsigned long va);
  71 extern unsigned long p_mapped_by_tlbcam(unsigned long pa);
  72 #else /* !HAVE_TLBCAM */
  73 #define v_mapped_by_tlbcam(x)   (0UL)
  74 #define p_mapped_by_tlbcam(x)   (0UL)
  75 #endif /* HAVE_TLBCAM */
  76
  77 #ifdef CONFIG_PTE_64BIT
  78 /* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
  79 #define PGDIR_ORDER     1
  80 #else
  81 #define PGDIR_ORDER     0
  82 #endif
  83
  84 pgd_t *pgd_alloc(struct mm_struct *mm)
  85 {
  86         pgd_t *ret;
  87
  88         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
  89         return ret;
  90 }
  91
  92 void pgd_free(pgd_t *pgd)
  93 {
  94         free_pages((unsigned long)pgd, PGDIR_ORDER);
  95 }
  96
  97 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  98 {
  99         pte_t *pte;
 100         extern int mem_init_done;
 101         extern void *early_get_page(void);
 102
 103         if (mem_init_done) {
 104                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 105         } else {
 106                 pte = (pte_t *)early_get_page();
 107                 if (pte)
 108                         clear_page(pte);
 109         }
 110         return pte;
 111 }
 112
 113 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 114 {
 115         struct page *ptepage;
 116
 117 #ifdef CONFIG_HIGHPTE
 118         int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
 119 #else
 120         int flags = GFP_KERNEL | __GFP_REPEAT;
 121 #endif
 122
 123         ptepage = alloc_pages(flags, 0);
 124         if (ptepage)
 125                 clear_highpage(ptepage);
 126         return ptepage;
 127 }
 128
 129 void pte_free_kernel(pte_t *pte)
 130 {
 131 #ifdef CONFIG_SMP
 132         hash_page_sync();
 133 #endif
 134         free_page((unsigned long)pte);
 135 }
 136
 137 void pte_free(struct page *ptepage)
 138 {
 139 #ifdef CONFIG_SMP
 140         hash_page_sync();
 141 #endif
 142         __free_page(ptepage);
 143 }
 144
 145 #ifndef CONFIG_PHYS_64BIT
 146 void __iomem *
 147 ioremap(phys_addr_t addr, unsigned long size)
 148 {
 149         return __ioremap(addr, size, _PAGE_NO_CACHE);
 150 }
 151 #else /* CONFIG_PHYS_64BIT */
 152 void __iomem *
 153 ioremap64(unsigned long long addr, unsigned long size)
 154 {
 155         return __ioremap(addr, size, _PAGE_NO_CACHE);
 156 }
 157
 158 void __iomem *
 159 ioremap(phys_addr_t addr, unsigned long size)
 160 {
 161         phys_addr_t addr64 = fixup_bigphys_addr(addr, size);
 162
 163         return ioremap64(addr64, size);
 164 }
 165 #endif /* CONFIG_PHYS_64BIT */
 166
 167 void __iomem *
 168 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 169 {
 170         unsigned long v, i;
 171         phys_addr_t p;
 172         int err;
 173
 174         /*
 175          * Choose an address to map it to.
 176          * Once the vmalloc system is running, we use it.
 177          * Before then, we use space going down from ioremap_base
 178          * (ioremap_bot records where we're up to).
 179          */
 180         p = addr & PAGE_MASK;
 181         size = PAGE_ALIGN(addr + size) - p;
 182
 183         /*
 184          * If the address lies within the first 16 MB, assume it's in ISA
 185          * memory space
 186          */
 187         if (p < 16*1024*1024)
 188                 p += _ISA_MEM_BASE;
 189
 190         /*
 191          * Don't allow anybody to remap normal RAM that we're using.
 192          * mem_init() sets high_memory so only do the check after that.
 193          */
 194         if ( mem_init_done && (p < virt_to_phys(high_memory)) )
 195         {
 196                 printk("__ioremap(): phys addr "PHYS_FMT" is RAM lr %p\n", p,
 197                        __builtin_return_address(0));
 198                 return NULL;
 199         }
 200
 201         if (size == 0)
 202                 return NULL;
 203
 204         /*
 205          * Is it already mapped?  Perhaps overlapped by a previous
 206          * BAT mapping.  If the whole area is mapped then we're done,
 207          * otherwise remap it since we want to keep the virt addrs for
 208          * each request contiguous.
 209          *
 210          * We make the assumption here that if the bottom and top
 211          * of the range we want are mapped then it's mapped to the
 212          * same virt address (and this is contiguous).
 213          *  -- Cort
 214          */
 215         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 216                 goto out;
 217
 218         if ((v = p_mapped_by_tlbcam(p)))
 219                 goto out;
 220
 221         if (mem_init_done) {
 222                 struct vm_struct *area;
 223                 area = get_vm_area(size, VM_IOREMAP);
 224                 if (area == 0)
 225                         return NULL;
 226                 v = (unsigned long) area->addr;
 227         } else {
 228                 v = (ioremap_bot -= size);
 229         }
 230
 231         if ((flags & _PAGE_PRESENT) == 0)
 232                 flags |= _PAGE_KERNEL;
 233         if (flags & _PAGE_NO_CACHE)
 234                 flags |= _PAGE_GUARDED;
 235
 236         /*
 237          * Should check if it is a candidate for a BAT mapping
 238          */
 239
 240         err = 0;
 241         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 242                 err = map_page(v+i, p+i, flags);
 243         if (err) {
 244                 if (mem_init_done)
 245                         vunmap((void *)v);
 246                 return NULL;
 247         }
 248
 249 out:
 250         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 251 }
 252
 253 void iounmap(volatile void __iomem *addr)
 254 {
 255         /*
 256          * If mapped by BATs then there is nothing to do.
 257          * Calling vfree() generates a benign warning.
 258          */
 259         if (v_mapped_by_bats((unsigned long)addr)) return;
 260
 261         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 262                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 263 }
 264
 265 void __iomem *ioport_map(unsigned long port, unsigned int len)
 266 {
 267         return (void __iomem *) (port + _IO_BASE);
 268 }
 269
 270 void ioport_unmap(void __iomem *addr)
 271 {
 272         /* Nothing to do */
 273 }
 274 EXPORT_SYMBOL(ioport_map);
 275 EXPORT_SYMBOL(ioport_unmap);
 276
 277 int
 278 map_page(unsigned long va, phys_addr_t pa, int flags)
 279 {
 280         pmd_t *pd;
 281         pte_t *pg;
 282         int err = -ENOMEM;
 283
 284         spin_lock(&init_mm.page_table_lock);
 285         /* Use upper 10 bits of VA to index the first level map */
 286         pd = pmd_offset(pgd_offset_k(va), va);
 287         /* Use middle 10 bits of VA to index the second-level map */
 288         pg = pte_alloc_kernel(&init_mm, pd, va);
 289         if (pg != 0) {
 290                 err = 0;
 291                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
 292                 if (mem_init_done)
 293                         flush_HPTE(0, va, pmd_val(*pd));
 294         }
 295         spin_unlock(&init_mm.page_table_lock);
 296         return err;
 297 }
 298
 299 /*
 300  * Map in all of physical memory starting at KERNELBASE.
 301  */
 302 void __init mapin_ram(void)
 303 {
 304         unsigned long v, p, s, f;
 305
 306         s = mmu_mapin_ram();
 307         v = KERNELBASE + s;
 308         p = PPC_MEMSTART + s;
 309         for (; s < total_lowmem; s += PAGE_SIZE) {
 310                 if ((char *) v >= _stext && (char *) v < etext)
 311                         f = _PAGE_RAM_TEXT;
 312                 else
 313                         f = _PAGE_RAM;
 314                 map_page(v, p, f);
 315                 v += PAGE_SIZE;
 316                 p += PAGE_SIZE;
 317         }
 318 }
 319
 320 /* is x a power of 2? */
 321 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 322
 323 /* is x a power of 4? */
 324 #define is_power_of_4(x)        ((x) != 0 && (((x) & (x-1)) == 0) && (ffs(x) & 1))
 325
 326 /*
 327  * Set up a mapping for a block of I/O.
 328  * virt, phys, size must all be page-aligned.
 329  * This should only be called before ioremap is called.
 330  */
 331 void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
 332                              unsigned int size, int flags)
 333 {
 334         int i;
 335
 336         if (virt > KERNELBASE && virt < ioremap_bot)
 337                 ioremap_bot = ioremap_base = virt;
 338
 339 #ifdef HAVE_BATS
 340         /*
 341          * Use a BAT for this if possible...
 342          */
 343         if (io_bat_index < 2 && is_power_of_2(size)
 344             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 345                 setbat(io_bat_index, virt, phys, size, flags);
 346                 ++io_bat_index;
 347                 return;
 348         }
 349 #endif /* HAVE_BATS */
 350
 351 #ifdef HAVE_TLBCAM
 352         /*
 353          * Use a CAM for this if possible...
 354          */
 355         if (tlbcam_index < num_tlbcam_entries && is_power_of_4(size)
 356             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 357                 settlbcam(tlbcam_index, virt, phys, size, flags, 0);
 358                 ++tlbcam_index;
 359                 return;
 360         }
 361 #endif /* HAVE_TLBCAM */
 362
 363         /* No BATs available, put it in the page tables. */
 364         for (i = 0; i < size; i += PAGE_SIZE)
 365                 map_page(virt + i, phys + i, flags);
 366 }
 367
 368 /* Scan the real Linux page tables and return a PTE pointer for
 369  * a virtual address in a context.
 370  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 371  * the PTE pointer is unmodified if PTE is not found.
 372  */
 373 int
 374 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
 375 {
 376         pgd_t   *pgd;
 377         pmd_t   *pmd;
 378         pte_t   *pte;
 379         int     retval = 0;
 380
 381         pgd = pgd_offset(mm, addr & PAGE_MASK);
 382         if (pgd) {
 383                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 384                 if (pmd_present(*pmd)) {
 385                         pte = pte_offset_map(pmd, addr & PAGE_MASK);
 386                         if (pte) {
 387                                 retval = 1;
 388                                 *ptep = pte;
 389                                 /* XXX caller needs to do pte_unmap, yuck */
 390                         }
 391                 }
 392         }
 393         return(retval);
 394 }
 395
 396 /* Find physical address for this virtual address.  Normally used by
 397  * I/O functions, but anyone can call it.
 398  */
 399 unsigned long iopa(unsigned long addr)
 400 {
 401         unsigned long pa;
 402
 403         /* I don't know why this won't work on PMacs or CHRP.  It
 404          * appears there is some bug, or there is some implicit
 405          * mapping done not properly represented by BATs or in page
 406          * tables.......I am actively working on resolving this, but
 407          * can't hold up other stuff.  -- Dan
 408          */
 409         pte_t *pte;
 410         struct mm_struct *mm;
 411
 412         /* Check the BATs */
 413         pa = v_mapped_by_bats(addr);
 414         if (pa)
 415                 return pa;
 416
 417         /* Allow mapping of user addresses (within the thread)
 418          * for DMA if necessary.
 419          */
 420         if (addr < TASK_SIZE)
 421                 mm = current->mm;
 422         else
 423                 mm = &init_mm;
 424
 425         pa = 0;
 426         if (get_pteptr(mm, addr, &pte)) {
 427                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 428                 pte_unmap(pte);
 429         }
 430
 431         return(pa);
 432 }
 433
 434 /* This is will find the virtual address for a physical one....
 435  * Swiped from APUS, could be dangerous :-).
 436  * This is only a placeholder until I really find a way to make this
 437  * work.  -- Dan
 438  */
 439 unsigned long
 440 mm_ptov (unsigned long paddr)
 441 {
 442         unsigned long ret;
 443 #if 0
 444         if (paddr < 16*1024*1024)
 445                 ret = ZTWO_VADDR(paddr);
 446         else {
 447                 int i;
 448
 449                 for (i = 0; i < kmap_chunk_count;){
 450                         unsigned long phys = kmap_chunks[i++];
 451                         unsigned long size = kmap_chunks[i++];
 452                         unsigned long virt = kmap_chunks[i++];
 453                         if (paddr >= phys
 454                             && paddr < (phys + size)){
 455                                 ret = virt + paddr - phys;
 456                                 goto exit;
 457                         }
 458                 }
 459
 460                 ret = (unsigned long) __va(paddr);
 461         }
 462 exit:
 463 #ifdef DEBUGPV
 464         printk ("PTOV(%lx)=%lx\n", paddr, ret);
 465 #endif
 466 #else
 467         ret = (unsigned long)paddr + KERNELBASE;
 468 #endif
 469         return ret;
 470 }
 471