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 #include <linux/mm_types.h>
  35
  36 #include <asm/pgtable.h>
  37 #include <asm/pgalloc.h>
  38 #include <linux/io.h>
  39 #include <asm/mmu.h>
  40 #include <asm/sections.h>
  41 #include <asm/fixmap.h>
  42
  43 unsigned long ioremap_base;
  44 unsigned long ioremap_bot;
  45 EXPORT_SYMBOL(ioremap_bot);
  46
  47 #ifndef CONFIG_SMP
  48 struct pgtable_cache_struct quicklists;
  49 #endif
  50
  51 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
  52                 unsigned long flags)
  53 {
  54         unsigned long v, i;
  55         phys_addr_t p;
  56         int err;
  57
  58         /*
  59          * Choose an address to map it to.
  60          * Once the vmalloc system is running, we use it.
  61          * Before then, we use space going down from ioremap_base
  62          * (ioremap_bot records where we're up to).
  63          */
  64         p = addr & PAGE_MASK;
  65         size = PAGE_ALIGN(addr + size) - p;
  66
  67         /*
  68          * Don't allow anybody to remap normal RAM that we're using.
  69          * mem_init() sets high_memory so only do the check after that.
  70          *
  71          * However, allow remap of rootfs: TBD
  72          */
  73
  74         if (mem_init_done &&
  75                 p >= memory_start && p < virt_to_phys(high_memory) &&
  76                 !(p >= __virt_to_phys((phys_addr_t)__bss_stop) &&
  77                 p < __virt_to_phys((phys_addr_t)__bss_stop))) {
  78                 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %pf\n",
  79                         (unsigned long)p, __builtin_return_address(0));
  80                 return NULL;
  81         }
  82
  83         if (size == 0)
  84                 return NULL;
  85
  86         /*
  87          * Is it already mapped? If the whole area is mapped then we're
  88          * done, otherwise remap it since we want to keep the virt addrs for
  89          * each request contiguous.
  90          *
  91          * We make the assumption here that if the bottom and top
  92          * of the range we want are mapped then it's mapped to the
  93          * same virt address (and this is contiguous).
  94          *  -- Cort
  95          */
  96
  97         if (mem_init_done) {
  98                 struct vm_struct *area;
  99                 area = get_vm_area(size, VM_IOREMAP);
 100                 if (area == NULL)
 101                         return NULL;
 102                 v = (unsigned long) area->addr;
 103         } else {
 104                 v = (ioremap_bot -= size);
 105         }
 106
 107         if ((flags & _PAGE_PRESENT) == 0)
 108                 flags |= _PAGE_KERNEL;
 109         if (flags & _PAGE_NO_CACHE)
 110                 flags |= _PAGE_GUARDED;
 111
 112         err = 0;
 113         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 114                 err = map_page(v + i, p + i, flags);
 115         if (err) {
 116                 if (mem_init_done)
 117                         vfree((void *)v);
 118                 return NULL;
 119         }
 120
 121         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 122 }
 123
 124 void __iomem *ioremap(phys_addr_t addr, unsigned long size)
 125 {
 126         return __ioremap(addr, size, _PAGE_NO_CACHE);
 127 }
 128 EXPORT_SYMBOL(ioremap);
 129
 130 void iounmap(volatile void __iomem *addr)
 131 {
 132         if ((__force void *)addr > high_memory &&
 133                                         (unsigned long) addr < ioremap_bot)
 134                 vfree((void *) (PAGE_MASK & (unsigned long) addr));
 135 }
 136 EXPORT_SYMBOL(iounmap);
 137
 138
 139 int map_page(unsigned long va, phys_addr_t pa, int flags)
 140 {
 141         pmd_t *pd;
 142         pte_t *pg;
 143         int err = -ENOMEM;
 144         /* Use upper 10 bits of VA to index the first level map */
 145         pd = pmd_offset(pgd_offset_k(va), va);
 146         /* Use middle 10 bits of VA to index the second-level map */
 147         pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
 148         /* pg = pte_alloc_kernel(&init_mm, pd, va); */
 149
 150         if (pg != NULL) {
 151                 err = 0;
 152                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 153                                 __pgprot(flags)));
 154                 if (unlikely(mem_init_done))
 155                         _tlbie(va);
 156         }
 157         return err;
 158 }
 159
 160 /*
 161  * Map in all of physical memory starting at CONFIG_KERNEL_START.
 162  */
 163 void __init mapin_ram(void)
 164 {
 165         unsigned long v, p, s, f;
 166
 167         v = CONFIG_KERNEL_START;
 168         p = memory_start;
 169         for (s = 0; s < lowmem_size; s += PAGE_SIZE) {
 170                 f = _PAGE_PRESENT | _PAGE_ACCESSED |
 171                                 _PAGE_SHARED | _PAGE_HWEXEC;
 172                 if ((char *) v < _stext || (char *) v >= _etext)
 173                         f |= _PAGE_WRENABLE;
 174                 else
 175                         /* On the MicroBlaze, no user access
 176                            forces R/W kernel access */
 177                         f |= _PAGE_USER;
 178                 map_page(v, p, f);
 179                 v += PAGE_SIZE;
 180                 p += PAGE_SIZE;
 181         }
 182 }
 183
 184 /* is x a power of 2? */
 185 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 186
 187 /* Scan the real Linux page tables and return a PTE pointer for
 188  * a virtual address in a context.
 189  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 190  * the PTE pointer is unmodified if PTE is not found.
 191  */
 192 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
 193 {
 194         pgd_t   *pgd;
 195         pmd_t   *pmd;
 196         pte_t   *pte;
 197         int     retval = 0;
 198
 199         pgd = pgd_offset(mm, addr & PAGE_MASK);
 200         if (pgd) {
 201                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 202                 if (pmd_present(*pmd)) {
 203                         pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
 204                         if (pte) {
 205                                 retval = 1;
 206                                 *ptep = pte;
 207                         }
 208                 }
 209         }
 210         return retval;
 211 }
 212
 213 /* Find physical address for this virtual address.  Normally used by
 214  * I/O functions, but anyone can call it.
 215  */
 216 unsigned long iopa(unsigned long addr)
 217 {
 218         unsigned long pa;
 219
 220         pte_t *pte;
 221         struct mm_struct *mm;
 222
 223         /* Allow mapping of user addresses (within the thread)
 224          * for DMA if necessary.
 225          */
 226         if (addr < TASK_SIZE)
 227                 mm = current->mm;
 228         else
 229                 mm = &init_mm;
 230
 231         pa = 0;
 232         if (get_pteptr(mm, addr, &pte))
 233                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 234
 235         return pa;
 236 }
 237
 238 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
 239                 unsigned long address)
 240 {
 241         pte_t *pte;
 242         if (mem_init_done) {
 243                 pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 244         } else {
 245                 pte = (pte_t *)early_get_page();
 246                 if (pte)
 247                         clear_page(pte);
 248         }
 249         return pte;
 250 }
 251
 252 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 253 {
 254         unsigned long address = __fix_to_virt(idx);
 255
 256         if (idx >= __end_of_fixed_addresses)
 257                 BUG();
 258
 259         map_page(address, phys, pgprot_val(flags));
 260 }