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_44x
  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         if ((ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGDIR_ORDER)) != NULL)
  89                 clear_pages(ret, PGDIR_ORDER);
  90         return ret;
  91 }
  92
  93 void pgd_free(pgd_t *pgd)
  94 {
  95         free_pages((unsigned long)pgd, PGDIR_ORDER);
  96 }
  97
  98 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  99 {
 100         pte_t *pte;
 101         extern int mem_init_done;
 102         extern void *early_get_page(void);
 103
 104         if (mem_init_done) {
 105                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
 106                 if (pte) {
 107                         struct page *ptepage = virt_to_page(pte);
 108                         ptepage->mapping = (void *) mm;
 109                         ptepage->index = address & PMD_MASK;
 110                 }
 111         } else
 112                 pte = (pte_t *)early_get_page();
 113         if (pte)
 114                 clear_page(pte);
 115         return pte;
 116 }
 117
 118 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 119 {
 120         struct page *ptepage;
 121
 122 #ifdef CONFIG_HIGHPTE
 123         int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
 124 #else
 125         int flags = GFP_KERNEL | __GFP_REPEAT;
 126 #endif
 127
 128         ptepage = alloc_pages(flags, 0);
 129         if (ptepage) {
 130                 ptepage->mapping = (void *) mm;
 131                 ptepage->index = address & PMD_MASK;
 132                 clear_highpage(ptepage);
 133         }
 134         return ptepage;
 135 }
 136
 137 void pte_free_kernel(pte_t *pte)
 138 {
 139 #ifdef CONFIG_SMP
 140         hash_page_sync();
 141 #endif
 142         virt_to_page(pte)->mapping = NULL;
 143         free_page((unsigned long)pte);
 144 }
 145
 146 void pte_free(struct page *ptepage)
 147 {
 148 #ifdef CONFIG_SMP
 149         hash_page_sync();
 150 #endif
 151         ptepage->mapping = NULL;
 152         __free_page(ptepage);
 153 }
 154
 155 #ifndef CONFIG_44x
 156 void *
 157 ioremap(phys_addr_t addr, unsigned long size)
 158 {
 159         return __ioremap(addr, size, _PAGE_NO_CACHE);
 160 }
 161 #else /* CONFIG_44x */
 162 void *
 163 ioremap64(unsigned long long addr, unsigned long size)
 164 {
 165         return __ioremap(addr, size, _PAGE_NO_CACHE);
 166 }
 167
 168 void *
 169 ioremap(phys_addr_t addr, unsigned long size)
 170 {
 171         phys_addr_t addr64 = fixup_bigphys_addr(addr, size);
 172
 173         return ioremap64(addr64, size);
 174 }
 175 #endif /* CONFIG_44x */
 176
 177 void *
 178 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 179 {
 180         unsigned long v, i;
 181         phys_addr_t p;
 182         int err;
 183
 184         /*
 185          * Choose an address to map it to.
 186          * Once the vmalloc system is running, we use it.
 187          * Before then, we use space going down from ioremap_base
 188          * (ioremap_bot records where we're up to).
 189          */
 190         p = addr & PAGE_MASK;
 191         size = PAGE_ALIGN(addr + size) - p;
 192
 193         /*
 194          * If the address lies within the first 16 MB, assume it's in ISA
 195          * memory space
 196          */
 197         if (p < 16*1024*1024)
 198                 p += _ISA_MEM_BASE;
 199
 200         /*
 201          * Don't allow anybody to remap normal RAM that we're using.
 202          * mem_init() sets high_memory so only do the check after that.
 203          */
 204         if ( mem_init_done && (p < virt_to_phys(high_memory)) )
 205         {
 206                 printk("__ioremap(): phys addr "PTE_FMT" is RAM lr %p\n", p,
 207                        __builtin_return_address(0));
 208                 return NULL;
 209         }
 210
 211         if (size == 0)
 212                 return NULL;
 213
 214         /*
 215          * Is it already mapped?  Perhaps overlapped by a previous
 216          * BAT mapping.  If the whole area is mapped then we're done,
 217          * otherwise remap it since we want to keep the virt addrs for
 218          * each request contiguous.
 219          *
 220          * We make the assumption here that if the bottom and top
 221          * of the range we want are mapped then it's mapped to the
 222          * same virt address (and this is contiguous).
 223          *  -- Cort
 224          */
 225         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 226                 goto out;
 227
 228         if ((v = p_mapped_by_tlbcam(p)))
 229                 goto out;
 230
 231         if (mem_init_done) {
 232                 struct vm_struct *area;
 233                 area = get_vm_area(size, VM_IOREMAP);
 234                 if (area == 0)
 235                         return NULL;
 236                 v = (unsigned long) area->addr;
 237         } else {
 238                 v = (ioremap_bot -= size);
 239         }
 240
 241         if ((flags & _PAGE_PRESENT) == 0)
 242                 flags |= _PAGE_KERNEL;
 243         if (flags & _PAGE_NO_CACHE)
 244                 flags |= _PAGE_GUARDED;
 245
 246         /*
 247          * Should check if it is a candidate for a BAT mapping
 248          */
 249
 250         err = 0;
 251         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 252                 err = map_page(v+i, p+i, flags);
 253         if (err) {
 254                 if (mem_init_done)
 255                         vunmap((void *)v);
 256                 return NULL;
 257         }
 258
 259 out:
 260         return (void *) (v + ((unsigned long)addr & ~PAGE_MASK));
 261 }
 262
 263 void iounmap(void *addr)
 264 {
 265         /*
 266          * If mapped by BATs then there is nothing to do.
 267          * Calling vfree() generates a benign warning.
 268          */
 269         if (v_mapped_by_bats((unsigned long)addr)) return;
 270
 271         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 272                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 273 }
 274
 275 void __iomem *ioport_map(unsigned long port, unsigned int len)
 276 {
 277         return (void __iomem *) (port + _IO_BASE);
 278 }
 279
 280 void ioport_unmap(void __iomem *addr)
 281 {
 282         /* Nothing to do */
 283 }
 284 EXPORT_SYMBOL(ioport_map);
 285 EXPORT_SYMBOL(ioport_unmap);
 286
 287 int
 288 map_page(unsigned long va, phys_addr_t pa, int flags)
 289 {
 290         pmd_t *pd;
 291         pte_t *pg;
 292         int err = -ENOMEM;
 293
 294         spin_lock(&init_mm.page_table_lock);
 295         /* Use upper 10 bits of VA to index the first level map */
 296         pd = pmd_offset(pgd_offset_k(va), va);
 297         /* Use middle 10 bits of VA to index the second-level map */
 298         pg = pte_alloc_kernel(&init_mm, pd, va);
 299         if (pg != 0) {
 300                 err = 0;
 301                 set_pte(pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
 302                 if (mem_init_done)
 303                         flush_HPTE(0, va, pmd_val(*pd));
 304         }
 305         spin_unlock(&init_mm.page_table_lock);
 306         return err;
 307 }
 308
 309 /*
 310  * Map in all of physical memory starting at KERNELBASE.
 311  */
 312 void __init mapin_ram(void)
 313 {
 314         unsigned long v, p, s, f;
 315
 316         s = mmu_mapin_ram();
 317         v = KERNELBASE + s;
 318         p = PPC_MEMSTART + s;
 319         for (; s < total_lowmem; s += PAGE_SIZE) {
 320                 if ((char *) v >= _stext && (char *) v < etext)
 321                         f = _PAGE_RAM_TEXT;
 322                 else
 323                         f = _PAGE_RAM;
 324                 map_page(v, p, f);
 325                 v += PAGE_SIZE;
 326                 p += PAGE_SIZE;
 327         }
 328 }
 329
 330 /* is x a power of 2? */
 331 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 332
 333 /* is x a power of 4? */
 334 #define is_power_of_4(x)        ((x) != 0 && (((x) & (x-1)) == 0) && (ffs(x) & 1))
 335
 336 /*
 337  * Set up a mapping for a block of I/O.
 338  * virt, phys, size must all be page-aligned.
 339  * This should only be called before ioremap is called.
 340  */
 341 void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
 342                              unsigned int size, int flags)
 343 {
 344         int i;
 345
 346         if (virt > KERNELBASE && virt < ioremap_bot)
 347                 ioremap_bot = ioremap_base = virt;
 348
 349 #ifdef HAVE_BATS
 350         /*
 351          * Use a BAT for this if possible...
 352          */
 353         if (io_bat_index < 2 && is_power_of_2(size)
 354             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 355                 setbat(io_bat_index, virt, phys, size, flags);
 356                 ++io_bat_index;
 357                 return;
 358         }
 359 #endif /* HAVE_BATS */
 360
 361 #ifdef HAVE_TLBCAM
 362         /*
 363          * Use a CAM for this if possible...
 364          */
 365         if (tlbcam_index < num_tlbcam_entries && is_power_of_4(size)
 366             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 367                 settlbcam(tlbcam_index, virt, phys, size, flags, 0);
 368                 ++tlbcam_index;
 369                 return;
 370         }
 371 #endif /* HAVE_TLBCAM */
 372
 373         /* No BATs available, put it in the page tables. */
 374         for (i = 0; i < size; i += PAGE_SIZE)
 375                 map_page(virt + i, phys + i, flags);
 376 }
 377
 378 /* Scan the real Linux page tables and return a PTE pointer for
 379  * a virtual address in a context.
 380  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 381  * the PTE pointer is unmodified if PTE is not found.
 382  */
 383 int
 384 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
 385 {
 386         pgd_t   *pgd;
 387         pmd_t   *pmd;
 388         pte_t   *pte;
 389         int     retval = 0;
 390
 391         pgd = pgd_offset(mm, addr & PAGE_MASK);
 392         if (pgd) {
 393                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 394                 if (pmd_present(*pmd)) {
 395                         pte = pte_offset_map(pmd, addr & PAGE_MASK);
 396                         if (pte) {
 397                                 retval = 1;
 398                                 *ptep = pte;
 399                                 /* XXX caller needs to do pte_unmap, yuck */
 400                         }
 401                 }
 402         }
 403         return(retval);
 404 }
 405
 406 /* Find physical address for this virtual address.  Normally used by
 407  * I/O functions, but anyone can call it.
 408  */
 409 unsigned long iopa(unsigned long addr)
 410 {
 411         unsigned long pa;
 412
 413         /* I don't know why this won't work on PMacs or CHRP.  It
 414          * appears there is some bug, or there is some implicit
 415          * mapping done not properly represented by BATs or in page
 416          * tables.......I am actively working on resolving this, but
 417          * can't hold up other stuff.  -- Dan
 418          */
 419         pte_t *pte;
 420         struct mm_struct *mm;
 421
 422         /* Check the BATs */
 423         pa = v_mapped_by_bats(addr);
 424         if (pa)
 425                 return pa;
 426
 427         /* Allow mapping of user addresses (within the thread)
 428          * for DMA if necessary.
 429          */
 430         if (addr < TASK_SIZE)
 431                 mm = current->mm;
 432         else
 433                 mm = &init_mm;
 434
 435         pa = 0;
 436         if (get_pteptr(mm, addr, &pte)) {
 437                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 438                 pte_unmap(pte);
 439         }
 440
 441         return(pa);
 442 }
 443
 444 /* This is will find the virtual address for a physical one....
 445  * Swiped from APUS, could be dangerous :-).
 446  * This is only a placeholder until I really find a way to make this
 447  * work.  -- Dan
 448  */
 449 unsigned long
 450 mm_ptov (unsigned long paddr)
 451 {
 452         unsigned long ret;
 453 #if 0
 454         if (paddr < 16*1024*1024)
 455                 ret = ZTWO_VADDR(paddr);
 456         else {
 457                 int i;
 458
 459                 for (i = 0; i < kmap_chunk_count;){
 460                         unsigned long phys = kmap_chunks[i++];
 461                         unsigned long size = kmap_chunks[i++];
 462                         unsigned long virt = kmap_chunks[i++];
 463                         if (paddr >= phys
 464                             && paddr < (phys + size)){
 465                                 ret = virt + paddr - phys;
 466                                 goto exit;
 467                         }
 468                 }
 469
 470                 ret = (unsigned long) __va(paddr);
 471         }
 472 exit:
 473 #ifdef DEBUGPV
 474         printk ("PTOV(%lx)=%lx\n", paddr, ret);
 475 #endif
 476 #else
 477         ret = (unsigned long)paddr + KERNELBASE;
 478 #endif
 479         return ret;
 480 }
 481