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/kernel.h>
  30 #include <linux/module.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 #define flush_HPTE(X, va, pg)   _tlbie(va)
  43
  44 unsigned long ioremap_base;
  45 unsigned long ioremap_bot;
  46 EXPORT_SYMBOL(ioremap_bot);
  47
  48 #ifndef CONFIG_SMP
  49 struct pgtable_cache_struct quicklists;
  50 #endif
  51
  52 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
  53                 unsigned long flags)
  54 {
  55         unsigned long v, i;
  56         phys_addr_t p;
  57         int err;
  58
  59         /*
  60          * Choose an address to map it to.
  61          * Once the vmalloc system is running, we use it.
  62          * Before then, we use space going down from ioremap_base
  63          * (ioremap_bot records where we're up to).
  64          */
  65         p = addr & PAGE_MASK;
  66         size = PAGE_ALIGN(addr + size) - p;
  67
  68         /*
  69          * Don't allow anybody to remap normal RAM that we're using.
  70          * mem_init() sets high_memory so only do the check after that.
  71          *
  72          * However, allow remap of rootfs: TBD
  73          */
  74         if (mem_init_done &&
  75                 p >= memory_start && p < virt_to_phys(high_memory) &&
  76                 !(p >= virt_to_phys((unsigned long)&__bss_stop) &&
  77                 p < virt_to_phys((unsigned long)__bss_stop))) {
  78                 printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT
  79                         " is RAM lr %pf\n", (unsigned long)p,
  80                         __builtin_return_address(0));
  81                 return NULL;
  82         }
  83
  84         if (size == 0)
  85                 return NULL;
  86
  87         /*
  88          * Is it already mapped? If the whole area is mapped then we're
  89          * done, otherwise remap it since we want to keep the virt addrs for
  90          * each request contiguous.
  91          *
  92          * We make the assumption here that if the bottom and top
  93          * of the range we want are mapped then it's mapped to the
  94          * same virt address (and this is contiguous).
  95          *  -- Cort
  96          */
  97
  98         if (mem_init_done) {
  99                 struct vm_struct *area;
 100                 area = get_vm_area(size, VM_IOREMAP);
 101                 if (area == NULL)
 102                         return NULL;
 103                 v = (unsigned long) area->addr;
 104         } else {
 105                 v = (ioremap_bot -= size);
 106         }
 107
 108         if ((flags & _PAGE_PRESENT) == 0)
 109                 flags |= _PAGE_KERNEL;
 110         if (flags & _PAGE_NO_CACHE)
 111                 flags |= _PAGE_GUARDED;
 112
 113         err = 0;
 114         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 115                 err = map_page(v + i, p + i, flags);
 116         if (err) {
 117                 if (mem_init_done)
 118                         vfree((void *)v);
 119                 return NULL;
 120         }
 121
 122         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 123 }
 124
 125 void __iomem *ioremap(phys_addr_t addr, unsigned long size)
 126 {
 127         return __ioremap(addr, size, _PAGE_NO_CACHE);
 128 }
 129 EXPORT_SYMBOL(ioremap);
 130
 131 void iounmap(void *addr)
 132 {
 133         if (addr > high_memory && (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                         flush_HPTE(0, va, pmd_val(*pd));
 156                         /* flush_HPTE(0, va, pg); */
 157         }
 158         return err;
 159 }
 160
 161 /*
 162  * Map in all of physical memory starting at CONFIG_KERNEL_START.
 163  */
 164 void __init mapin_ram(void)
 165 {
 166         unsigned long v, p, s, f;
 167
 168         v = CONFIG_KERNEL_START;
 169         p = memory_start;
 170         for (s = 0; s < lowmem_size; s += PAGE_SIZE) {
 171                 f = _PAGE_PRESENT | _PAGE_ACCESSED |
 172                                 _PAGE_SHARED | _PAGE_HWEXEC;
 173                 if ((char *) v < _stext || (char *) v >= _etext)
 174                         f |= _PAGE_WRENABLE;
 175                 else
 176                         /* On the MicroBlaze, no user access
 177                            forces R/W kernel access */
 178                         f |= _PAGE_USER;
 179                 map_page(v, p, f);
 180                 v += PAGE_SIZE;
 181                 p += PAGE_SIZE;
 182         }
 183 }
 184
 185 /* is x a power of 2? */
 186 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 187
 188 /* Scan the real Linux page tables and return a PTE pointer for
 189  * a virtual address in a context.
 190  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 191  * the PTE pointer is unmodified if PTE is not found.
 192  */
 193 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
 194 {
 195         pgd_t   *pgd;
 196         pmd_t   *pmd;
 197         pte_t   *pte;
 198         int     retval = 0;
 199
 200         pgd = pgd_offset(mm, addr & PAGE_MASK);
 201         if (pgd) {
 202                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 203                 if (pmd_present(*pmd)) {
 204                         pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
 205                         if (pte) {
 206                                 retval = 1;
 207                                 *ptep = pte;
 208                         }
 209                 }
 210         }
 211         return retval;
 212 }
 213
 214 /* Find physical address for this virtual address.  Normally used by
 215  * I/O functions, but anyone can call it.
 216  */
 217 unsigned long iopa(unsigned long addr)
 218 {
 219         unsigned long pa;
 220
 221         pte_t *pte;
 222         struct mm_struct *mm;
 223
 224         /* Allow mapping of user addresses (within the thread)
 225          * for DMA if necessary.
 226          */
 227         if (addr < TASK_SIZE)
 228                 mm = current->mm;
 229         else
 230                 mm = &init_mm;
 231
 232         pa = 0;
 233         if (get_pteptr(mm, addr, &pte))
 234                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 235
 236         return pa;
 237 }
 238
 239 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
 240                 unsigned long address)
 241 {
 242         pte_t *pte;
 243         if (mem_init_done) {
 244                 pte = (pte_t *)__get_free_page(GFP_KERNEL |
 245                                         __GFP_REPEAT | __GFP_ZERO);
 246         } else {
 247                 pte = (pte_t *)early_get_page();
 248                 if (pte)
 249                         clear_page(pte);
 250         }
 251         return pte;
 252 }
 253
 254 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 255 {
 256         unsigned long address = __fix_to_virt(idx);
 257
 258         if (idx >= __end_of_fixed_addresses)
 259                 BUG();
 260
 261         map_page(address, phys, pgprot_val(flags));
 262 }