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  *  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 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
  41 int io_bat_index;
  42
  43 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
  44 #define HAVE_BATS       1
  45 #endif
  46
  47 #if defined(CONFIG_FSL_BOOKE)
  48 #define HAVE_TLBCAM     1
  49 #endif
  50
  51 extern char etext[], _stext[];
  52
  53 #ifdef CONFIG_SMP
  54 extern void hash_page_sync(void);
  55 #endif
  56
  57 #ifdef HAVE_BATS
  58 extern unsigned long v_mapped_by_bats(unsigned long va);
  59 extern unsigned long p_mapped_by_bats(unsigned long pa);
  60 void setbat(int index, unsigned long virt, unsigned long phys,
  61             unsigned int size, int flags);
  62
  63 #else /* !HAVE_BATS */
  64 #define v_mapped_by_bats(x)     (0UL)
  65 #define p_mapped_by_bats(x)     (0UL)
  66 #endif /* HAVE_BATS */
  67
  68 #ifdef HAVE_TLBCAM
  69 extern unsigned int tlbcam_index;
  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         gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
 119 #else
 120         gfp_t 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 EXPORT_SYMBOL(ioremap64);
 158
 159 void __iomem *
 160 ioremap(phys_addr_t addr, unsigned long size)
 161 {
 162         phys_addr_t addr64 = fixup_bigphys_addr(addr, size);
 163
 164         return ioremap64(addr64, size);
 165 }
 166 #endif /* CONFIG_PHYS_64BIT */
 167 EXPORT_SYMBOL(ioremap);
 168
 169 void __iomem *
 170 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 171 {
 172         unsigned long v, i;
 173         phys_addr_t p;
 174         int err;
 175
 176         /*
 177          * Choose an address to map it to.
 178          * Once the vmalloc system is running, we use it.
 179          * Before then, we use space going down from ioremap_base
 180          * (ioremap_bot records where we're up to).
 181          */
 182         p = addr & PAGE_MASK;
 183         size = PAGE_ALIGN(addr + size) - p;
 184
 185         /*
 186          * If the address lies within the first 16 MB, assume it's in ISA
 187          * memory space
 188          */
 189         if (p < 16*1024*1024)
 190                 p += _ISA_MEM_BASE;
 191
 192         /*
 193          * Don't allow anybody to remap normal RAM that we're using.
 194          * mem_init() sets high_memory so only do the check after that.
 195          */
 196         if (mem_init_done && (p < virt_to_phys(high_memory))) {
 197                 printk("__ioremap(): phys addr "PHYS_FMT" is RAM lr %p\n", p,
 198                        __builtin_return_address(0));
 199                 return NULL;
 200         }
 201
 202         if (size == 0)
 203                 return NULL;
 204
 205         /*
 206          * Is it already mapped?  Perhaps overlapped by a previous
 207          * BAT mapping.  If the whole area is mapped then we're done,
 208          * otherwise remap it since we want to keep the virt addrs for
 209          * each request contiguous.
 210          *
 211          * We make the assumption here that if the bottom and top
 212          * of the range we want are mapped then it's mapped to the
 213          * same virt address (and this is contiguous).
 214          *  -- Cort
 215          */
 216         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 217                 goto out;
 218
 219         if ((v = p_mapped_by_tlbcam(p)))
 220                 goto out;
 221
 222         if (mem_init_done) {
 223                 struct vm_struct *area;
 224                 area = get_vm_area(size, VM_IOREMAP);
 225                 if (area == 0)
 226                         return NULL;
 227                 v = (unsigned long) area->addr;
 228         } else {
 229                 v = (ioremap_bot -= size);
 230         }
 231
 232         if ((flags & _PAGE_PRESENT) == 0)
 233                 flags |= _PAGE_KERNEL;
 234         if (flags & _PAGE_NO_CACHE)
 235                 flags |= _PAGE_GUARDED;
 236
 237         /*
 238          * Should check if it is a candidate for a BAT mapping
 239          */
 240
 241         err = 0;
 242         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 243                 err = map_page(v+i, p+i, flags);
 244         if (err) {
 245                 if (mem_init_done)
 246                         vunmap((void *)v);
 247                 return NULL;
 248         }
 249
 250 out:
 251         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 252 }
 253 EXPORT_SYMBOL(__ioremap);
 254
 255 void iounmap(volatile void __iomem *addr)
 256 {
 257         /*
 258          * If mapped by BATs then there is nothing to do.
 259          * Calling vfree() generates a benign warning.
 260          */
 261         if (v_mapped_by_bats((unsigned long)addr)) return;
 262
 263         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 264                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 265 }
 266 EXPORT_SYMBOL(iounmap);
 267
 268 void __iomem *ioport_map(unsigned long port, unsigned int len)
 269 {
 270         return (void __iomem *) (port + _IO_BASE);
 271 }
 272
 273 void ioport_unmap(void __iomem *addr)
 274 {
 275         /* Nothing to do */
 276 }
 277 EXPORT_SYMBOL(ioport_map);
 278 EXPORT_SYMBOL(ioport_unmap);
 279
 280 int
 281 map_page(unsigned long va, phys_addr_t pa, int flags)
 282 {
 283         pmd_t *pd;
 284         pte_t *pg;
 285         int err = -ENOMEM;
 286
 287         /* Use upper 10 bits of VA to index the first level map */
 288         pd = pmd_offset(pgd_offset_k(va), va);
 289         /* Use middle 10 bits of VA to index the second-level map */
 290         pg = pte_alloc_kernel(pd, va);
 291         if (pg != 0) {
 292                 err = 0;
 293                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
 294                 if (mem_init_done)
 295                         flush_HPTE(0, va, pmd_val(*pd));
 296         }
 297         return err;
 298 }
 299
 300 /*
 301  * Map in all of physical memory starting at KERNELBASE.
 302  */
 303 void __init mapin_ram(void)
 304 {
 305         unsigned long v, p, s, f;
 306
 307         s = mmu_mapin_ram();
 308         v = KERNELBASE + s;
 309         p = PPC_MEMSTART + s;
 310         for (; s < total_lowmem; s += PAGE_SIZE) {
 311                 if ((char *) v >= _stext && (char *) v < etext)
 312                         f = _PAGE_RAM_TEXT;
 313                 else
 314                         f = _PAGE_RAM;
 315                 map_page(v, p, f);
 316                 v += PAGE_SIZE;
 317                 p += PAGE_SIZE;
 318         }
 319 }
 320
 321 /* is x a power of 2? */
 322 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 323
 324 /* is x a power of 4? */
 325 #define is_power_of_4(x)        ((x) != 0 && (((x) & (x-1)) == 0) && (ffs(x) & 1))
 326
 327 /*
 328  * Set up a mapping for a block of I/O.
 329  * virt, phys, size must all be page-aligned.
 330  * This should only be called before ioremap is called.
 331  */
 332 void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
 333                              unsigned int size, int flags)
 334 {
 335         int i;
 336
 337         if (virt > KERNELBASE && virt < ioremap_bot)
 338                 ioremap_bot = ioremap_base = virt;
 339
 340 #ifdef HAVE_BATS
 341         /*
 342          * Use a BAT for this if possible...
 343          */
 344         if (io_bat_index < 2 && is_power_of_2(size)
 345             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 346                 setbat(io_bat_index, virt, phys, size, flags);
 347                 ++io_bat_index;
 348                 return;
 349         }
 350 #endif /* HAVE_BATS */
 351
 352 #ifdef HAVE_TLBCAM
 353         /*
 354          * Use a CAM for this if possible...
 355          */
 356         if (tlbcam_index < num_tlbcam_entries && is_power_of_4(size)
 357             && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
 358                 settlbcam(tlbcam_index, virt, phys, size, flags, 0);
 359                 ++tlbcam_index;
 360                 return;
 361         }
 362 #endif /* HAVE_TLBCAM */
 363
 364         /* No BATs available, put it in the page tables. */
 365         for (i = 0; i < size; i += PAGE_SIZE)
 366                 map_page(virt + i, phys + i, flags);
 367 }
 368
 369 /* Scan the real Linux page tables and return a PTE pointer for
 370  * a virtual address in a context.
 371  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 372  * the PTE pointer is unmodified if PTE is not found.
 373  */
 374 int
 375 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 376 {
 377         pgd_t   *pgd;
 378         pmd_t   *pmd;
 379         pte_t   *pte;
 380         int     retval = 0;
 381
 382         pgd = pgd_offset(mm, addr & PAGE_MASK);
 383         if (pgd) {
 384                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 385                 if (pmd_present(*pmd)) {
 386                         pte = pte_offset_map(pmd, addr & PAGE_MASK);
 387                         if (pte) {
 388                                 retval = 1;
 389                                 *ptep = pte;
 390                                 if (pmdp)
 391                                         *pmdp = pmd;
 392                                 /* XXX caller needs to do pte_unmap, yuck */
 393                         }
 394                 }
 395         }
 396         return(retval);
 397 }
 398
 399 /* Find physical address for this virtual address.  Normally used by
 400  * I/O functions, but anyone can call it.
 401  */
 402 unsigned long iopa(unsigned long addr)
 403 {
 404         unsigned long pa;
 405
 406         /* I don't know why this won't work on PMacs or CHRP.  It
 407          * appears there is some bug, or there is some implicit
 408          * mapping done not properly represented by BATs or in page
 409          * tables.......I am actively working on resolving this, but
 410          * can't hold up other stuff.  -- Dan
 411          */
 412         pte_t *pte;
 413         struct mm_struct *mm;
 414
 415         /* Check the BATs */
 416         pa = v_mapped_by_bats(addr);
 417         if (pa)
 418                 return pa;
 419
 420         /* Allow mapping of user addresses (within the thread)
 421          * for DMA if necessary.
 422          */
 423         if (addr < TASK_SIZE)
 424                 mm = current->mm;
 425         else
 426                 mm = &init_mm;
 427
 428         pa = 0;
 429         if (get_pteptr(mm, addr, &pte, NULL)) {
 430                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 431                 pte_unmap(pte);
 432         }
 433
 434         return(pa);
 435 }
 436
 437 /* This is will find the virtual address for a physical one....
 438  * Swiped from APUS, could be dangerous :-).
 439  * This is only a placeholder until I really find a way to make this
 440  * work.  -- Dan
 441  */
 442 unsigned long
 443 mm_ptov (unsigned long paddr)
 444 {
 445         unsigned long ret;
 446 #if 0
 447         if (paddr < 16*1024*1024)
 448                 ret = ZTWO_VADDR(paddr);
 449         else {
 450                 int i;
 451
 452                 for (i = 0; i < kmap_chunk_count;){
 453                         unsigned long phys = kmap_chunks[i++];
 454                         unsigned long size = kmap_chunks[i++];
 455                         unsigned long virt = kmap_chunks[i++];
 456                         if (paddr >= phys
 457                             && paddr < (phys + size)){
 458                                 ret = virt + paddr - phys;
 459                                 goto exit;
 460                         }
 461                 }
 462
 463                 ret = (unsigned long) __va(paddr);
 464         }
 465 exit:
 466 #ifdef DEBUGPV
 467         printk ("PTOV(%lx)=%lx\n", paddr, ret);
 468 #endif
 469 #else
 470         ret = (unsigned long)paddr + KERNELBASE;
 471 #endif
 472         return ret;
 473 }
 474