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/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 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
  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 __init_refok 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         gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
 118 #else
 119         gfp_t 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 void __iomem *
 145 ioremap(phys_addr_t addr, unsigned long size)
 146 {
 147         return __ioremap(addr, size, _PAGE_NO_CACHE);
 148 }
 149 EXPORT_SYMBOL(ioremap);
 150
 151 void __iomem *
 152 ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
 153 {
 154         return __ioremap(addr, size, flags);
 155 }
 156 EXPORT_SYMBOL(ioremap_flags);
 157
 158 void __iomem *
 159 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 160 {
 161         unsigned long v, i;
 162         phys_addr_t p;
 163         int err;
 164
 165         /*
 166          * Choose an address to map it to.
 167          * Once the vmalloc system is running, we use it.
 168          * Before then, we use space going down from ioremap_base
 169          * (ioremap_bot records where we're up to).
 170          */
 171         p = addr & PAGE_MASK;
 172         size = PAGE_ALIGN(addr + size) - p;
 173
 174         /*
 175          * If the address lies within the first 16 MB, assume it's in ISA
 176          * memory space
 177          */
 178         if (p < 16*1024*1024)
 179                 p += _ISA_MEM_BASE;
 180
 181         /*
 182          * Don't allow anybody to remap normal RAM that we're using.
 183          * mem_init() sets high_memory so only do the check after that.
 184          */
 185         if (mem_init_done && (p < virt_to_phys(high_memory))) {
 186                 printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
 187                        (unsigned long long)p, __builtin_return_address(0));
 188                 return NULL;
 189         }
 190
 191         if (size == 0)
 192                 return NULL;
 193
 194         /*
 195          * Is it already mapped?  Perhaps overlapped by a previous
 196          * BAT mapping.  If the whole area is mapped then we're done,
 197          * otherwise remap it since we want to keep the virt addrs for
 198          * each request contiguous.
 199          *
 200          * We make the assumption here that if the bottom and top
 201          * of the range we want are mapped then it's mapped to the
 202          * same virt address (and this is contiguous).
 203          *  -- Cort
 204          */
 205         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 206                 goto out;
 207
 208         if ((v = p_mapped_by_tlbcam(p)))
 209                 goto out;
 210
 211         if (mem_init_done) {
 212                 struct vm_struct *area;
 213                 area = get_vm_area(size, VM_IOREMAP);
 214                 if (area == 0)
 215                         return NULL;
 216                 v = (unsigned long) area->addr;
 217         } else {
 218                 v = (ioremap_bot -= size);
 219         }
 220
 221         if ((flags & _PAGE_PRESENT) == 0)
 222                 flags |= _PAGE_KERNEL;
 223         if (flags & _PAGE_NO_CACHE)
 224                 flags |= _PAGE_GUARDED;
 225
 226         /*
 227          * Should check if it is a candidate for a BAT mapping
 228          */
 229
 230         err = 0;
 231         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 232                 err = map_page(v+i, p+i, flags);
 233         if (err) {
 234                 if (mem_init_done)
 235                         vunmap((void *)v);
 236                 return NULL;
 237         }
 238
 239 out:
 240         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 241 }
 242 EXPORT_SYMBOL(__ioremap);
 243
 244 void iounmap(volatile void __iomem *addr)
 245 {
 246         /*
 247          * If mapped by BATs then there is nothing to do.
 248          * Calling vfree() generates a benign warning.
 249          */
 250         if (v_mapped_by_bats((unsigned long)addr)) return;
 251
 252         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 253                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 254 }
 255 EXPORT_SYMBOL(iounmap);
 256
 257 int map_page(unsigned long va, phys_addr_t pa, int flags)
 258 {
 259         pmd_t *pd;
 260         pte_t *pg;
 261         int err = -ENOMEM;
 262
 263         /* Use upper 10 bits of VA to index the first level map */
 264         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 265         /* Use middle 10 bits of VA to index the second-level map */
 266         pg = pte_alloc_kernel(pd, va);
 267         if (pg != 0) {
 268                 err = 0;
 269                 /* The PTE should never be already set nor present in the
 270                  * hash table
 271                  */
 272                 BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
 273                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 274                                                      __pgprot(flags)));
 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         int ktext;
 286
 287         s = mmu_mapin_ram();
 288         v = KERNELBASE + s;
 289         p = PPC_MEMSTART + s;
 290         for (; s < total_lowmem; s += PAGE_SIZE) {
 291                 ktext = ((char *) v >= _stext && (char *) v < etext);
 292                 f = ktext ?_PAGE_RAM_TEXT : _PAGE_RAM;
 293                 map_page(v, p, f);
 294 #ifdef CONFIG_PPC_STD_MMU_32
 295                 if (ktext)
 296                         hash_preload(&init_mm, v, 0, 0x300);
 297 #endif
 298                 v += PAGE_SIZE;
 299                 p += PAGE_SIZE;
 300         }
 301 }
 302
 303 /* is x a power of 4? */
 304 #define is_power_of_4(x)        is_power_of_2(x) && (ffs(x) & 1)
 305
 306 /* Scan the real Linux page tables and return a PTE pointer for
 307  * a virtual address in a context.
 308  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 309  * the PTE pointer is unmodified if PTE is not found.
 310  */
 311 int
 312 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 313 {
 314         pgd_t   *pgd;
 315         pud_t   *pud;
 316         pmd_t   *pmd;
 317         pte_t   *pte;
 318         int     retval = 0;
 319
 320         pgd = pgd_offset(mm, addr & PAGE_MASK);
 321         if (pgd) {
 322                 pud = pud_offset(pgd, addr & PAGE_MASK);
 323                 if (pud && pud_present(*pud)) {
 324                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 325                         if (pmd_present(*pmd)) {
 326                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 327                                 if (pte) {
 328                                         retval = 1;
 329                                         *ptep = pte;
 330                                         if (pmdp)
 331                                                 *pmdp = pmd;
 332                                         /* XXX caller needs to do pte_unmap, yuck */
 333                                 }
 334                         }
 335                 }
 336         }
 337         return(retval);
 338 }
 339
 340 #ifdef CONFIG_DEBUG_PAGEALLOC
 341
 342 static int __change_page_attr(struct page *page, pgprot_t prot)
 343 {
 344         pte_t *kpte;
 345         pmd_t *kpmd;
 346         unsigned long address;
 347
 348         BUG_ON(PageHighMem(page));
 349         address = (unsigned long)page_address(page);
 350
 351         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 352                 return 0;
 353         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 354                 return -EINVAL;
 355         set_pte_at(&init_mm, address, kpte, mk_pte(page, prot));
 356         wmb();
 357         flush_HPTE(0, address, pmd_val(*kpmd));
 358         pte_unmap(kpte);
 359
 360         return 0;
 361 }
 362
 363 /*
 364  * Change the page attributes of an page in the linear mapping.
 365  *
 366  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 367  */
 368 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 369 {
 370         int i, err = 0;
 371         unsigned long flags;
 372
 373         local_irq_save(flags);
 374         for (i = 0; i < numpages; i++, page++) {
 375                 err = __change_page_attr(page, prot);
 376                 if (err)
 377                         break;
 378         }
 379         local_irq_restore(flags);
 380         return err;
 381 }
 382
 383
 384 void kernel_map_pages(struct page *page, int numpages, int enable)
 385 {
 386         if (PageHighMem(page))
 387                 return;
 388
 389         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 390 }
 391 #endif /* CONFIG_DEBUG_PAGEALLOC */