arch/microblaze/mm/pgtable.c

   1 /*
   2  *  This file contains the routines setting up the linux page tables.
   3  *
   4  * Copyright (C) 2008 Michal Simek
   5  * Copyright (C) 2008 PetaLogix
   6  *
   7  *    Copyright (C) 2007 Xilinx, Inc.  All rights reserved.
   8  *
   9  *  Derived from arch/ppc/mm/pgtable.c:
  10  *    -- paulus
  11  *
  12  *  Derived from arch/ppc/mm/init.c:
  13  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  14  *
  15  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  16  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  17  *    Copyright (C) 1996 Paul Mackerras
  18  *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
  19  *
  20  *  Derived from "arch/i386/mm/init.c"
  21  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  22  *
  23  *  This file is subject to the terms and conditions of the GNU General
  24  *  Public License.  See the file COPYING in the main directory of this
  25  *  archive for more details.
  26  *
  27  */
  28
  29 #include <linux/export.h>
  30 #include <linux/kernel.h>
  31 #include <linux/types.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/init.h>
  34
  35 #include <asm/pgtable.h>
  36 #include <asm/pgalloc.h>
  37 #include <linux/io.h>
  38 #include <asm/mmu.h>
  39 #include <asm/sections.h>
  40 #include <asm/fixmap.h>
  41
  42 unsigned long ioremap_base;
  43 unsigned long ioremap_bot;
  44 EXPORT_SYMBOL(ioremap_bot);
  45
  46 #ifndef CONFIG_SMP
  47 struct pgtable_cache_struct quicklists;
  48 #endif
  49
  50 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
  51                 unsigned long flags)
  52 {
  53         unsigned long v, i;
  54         phys_addr_t p;
  55         int err;
  56
  57         /*
  58          * Choose an address to map it to.
  59          * Once the vmalloc system is running, we use it.
  60          * Before then, we use space going down from ioremap_base
  61          * (ioremap_bot records where we're up to).
  62          */
  63         p = addr & PAGE_MASK;
  64         size = PAGE_ALIGN(addr + size) - p;
  65
  66         /*
  67          * Don't allow anybody to remap normal RAM that we're using.
  68          * mem_init() sets high_memory so only do the check after that.
  69          *
  70          * However, allow remap of rootfs: TBD
  71          */
  72         if (mem_init_done &&
  73                 p >= memory_start && p < virt_to_phys(high_memory) &&
  74                 !(p >= virt_to_phys((unsigned long)&__bss_stop) &&
  75                 p < virt_to_phys((unsigned long)__bss_stop))) {
  76                 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %pf\n",
  77                         (unsigned long)p, __builtin_return_address(0));
  78                 return NULL;
  79         }
  80
  81         if (size == 0)
  82                 return NULL;
  83
  84         /*
  85          * Is it already mapped? If the whole area is mapped then we're
  86          * done, otherwise remap it since we want to keep the virt addrs for
  87          * each request contiguous.
  88          *
  89          * We make the assumption here that if the bottom and top
  90          * of the range we want are mapped then it's mapped to the
  91          * same virt address (and this is contiguous).
  92          *  -- Cort
  93          */
  94
  95         if (mem_init_done) {
  96                 struct vm_struct *area;
  97                 area = get_vm_area(size, VM_IOREMAP);
  98                 if (area == NULL)
  99                         return NULL;
 100                 v = (unsigned long) area->addr;
 101         } else {
 102                 v = (ioremap_bot -= size);
 103         }
 104
 105         if ((flags & _PAGE_PRESENT) == 0)
 106                 flags |= _PAGE_KERNEL;
 107         if (flags & _PAGE_NO_CACHE)
 108                 flags |= _PAGE_GUARDED;
 109
 110         err = 0;
 111         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 112                 err = map_page(v + i, p + i, flags);
 113         if (err) {
 114                 if (mem_init_done)
 115                         vfree((void *)v);
 116                 return NULL;
 117         }
 118
 119         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 120 }
 121
 122 void __iomem *ioremap(phys_addr_t addr, unsigned long size)
 123 {
 124         return __ioremap(addr, size, _PAGE_NO_CACHE);
 125 }
 126 EXPORT_SYMBOL(ioremap);
 127
 128 void iounmap(void __iomem *addr)
 129 {
 130         if ((__force void *)addr > high_memory &&
 131                                         (unsigned long) addr < ioremap_bot)
 132                 vfree((void *) (PAGE_MASK & (unsigned long) addr));
 133 }
 134 EXPORT_SYMBOL(iounmap);
 135
 136
 137 int map_page(unsigned long va, phys_addr_t pa, int flags)
 138 {
 139         pmd_t *pd;
 140         pte_t *pg;
 141         int err = -ENOMEM;
 142         /* Use upper 10 bits of VA to index the first level map */
 143         pd = pmd_offset(pgd_offset_k(va), va);
 144         /* Use middle 10 bits of VA to index the second-level map */
 145         pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
 146         /* pg = pte_alloc_kernel(&init_mm, pd, va); */
 147
 148         if (pg != NULL) {
 149                 err = 0;
 150                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 151                                 __pgprot(flags)));
 152                 if (unlikely(mem_init_done))
 153                         _tlbie(va);
 154         }
 155         return err;
 156 }
 157
 158 /*
 159  * Map in all of physical memory starting at CONFIG_KERNEL_START.
 160  */
 161 void __init mapin_ram(void)
 162 {
 163         unsigned long v, p, s, f;
 164
 165         v = CONFIG_KERNEL_START;
 166         p = memory_start;
 167         for (s = 0; s < lowmem_size; s += PAGE_SIZE) {
 168                 f = _PAGE_PRESENT | _PAGE_ACCESSED |
 169                                 _PAGE_SHARED | _PAGE_HWEXEC;
 170                 if ((char *) v < _stext || (char *) v >= _etext)
 171                         f |= _PAGE_WRENABLE;
 172                 else
 173                         /* On the MicroBlaze, no user access
 174                            forces R/W kernel access */
 175                         f |= _PAGE_USER;
 176                 map_page(v, p, f);
 177                 v += PAGE_SIZE;
 178                 p += PAGE_SIZE;
 179         }
 180 }
 181
 182 /* is x a power of 2? */
 183 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 184
 185 /* Scan the real Linux page tables and return a PTE pointer for
 186  * a virtual address in a context.
 187  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 188  * the PTE pointer is unmodified if PTE is not found.
 189  */
 190 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
 191 {
 192         pgd_t   *pgd;
 193         pmd_t   *pmd;
 194         pte_t   *pte;
 195         int     retval = 0;
 196
 197         pgd = pgd_offset(mm, addr & PAGE_MASK);
 198         if (pgd) {
 199                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 200                 if (pmd_present(*pmd)) {
 201                         pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
 202                         if (pte) {
 203                                 retval = 1;
 204                                 *ptep = pte;
 205                         }
 206                 }
 207         }
 208         return retval;
 209 }
 210
 211 /* Find physical address for this virtual address.  Normally used by
 212  * I/O functions, but anyone can call it.
 213  */
 214 unsigned long iopa(unsigned long addr)
 215 {
 216         unsigned long pa;
 217
 218         pte_t *pte;
 219         struct mm_struct *mm;
 220
 221         /* Allow mapping of user addresses (within the thread)
 222          * for DMA if necessary.
 223          */
 224         if (addr < TASK_SIZE)
 225                 mm = current->mm;
 226         else
 227                 mm = &init_mm;
 228
 229         pa = 0;
 230         if (get_pteptr(mm, addr, &pte))
 231                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 232
 233         return pa;
 234 }
 235
 236 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
 237                 unsigned long address)
 238 {
 239         pte_t *pte;
 240         if (mem_init_done) {
 241                 pte = (pte_t *)__get_free_page(GFP_KERNEL |
 242                                         __GFP_REPEAT | __GFP_ZERO);
 243         } else {
 244                 pte = (pte_t *)early_get_page();
 245                 if (pte)
 246                         clear_page(pte);
 247         }
 248         return pte;
 249 }
 250
 251 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 252 {
 253         unsigned long address = __fix_to_virt(idx);
 254
 255         if (idx >= __end_of_fixed_addresses)
 256                 BUG();
 257
 258         map_page(address, phys, pgprot_val(flags));
 259 }