arch/powerpc/mm/pgtable_64.c

   1 /*
   2  *  This file contains ioremap and related functions for 64-bit machines.
   3  *
   4  *  Derived from arch/ppc64/mm/init.c
   5  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   6  *
   7  *  Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
   8  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
   9  *    Copyright (C) 1996 Paul Mackerras
  10  *
  11  *  Derived from "arch/i386/mm/init.c"
  12  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  13  *
  14  *  Dave Engebretsen <engebret@us.ibm.com>
  15  *      Rework for PPC64 port.
  16  *
  17  *  This program is free software; you can redistribute it and/or
  18  *  modify it under the terms of the GNU General Public License
  19  *  as published by the Free Software Foundation; either version
  20  *  2 of the License, or (at your option) any later version.
  21  *
  22  */
  23
  24 #include <linux/signal.h>
  25 #include <linux/sched.h>
  26 #include <linux/kernel.h>
  27 #include <linux/errno.h>
  28 #include <linux/string.h>
  29 #include <linux/types.h>
  30 #include <linux/mman.h>
  31 #include <linux/mm.h>
  32 #include <linux/swap.h>
  33 #include <linux/stddef.h>
  34 #include <linux/vmalloc.h>
  35 #include <linux/init.h>
  36
  37 #include <asm/pgalloc.h>
  38 #include <asm/page.h>
  39 #include <asm/prom.h>
  40 #include <asm/io.h>
  41 #include <asm/mmu_context.h>
  42 #include <asm/pgtable.h>
  43 #include <asm/mmu.h>
  44 #include <asm/smp.h>
  45 #include <asm/machdep.h>
  46 #include <asm/tlb.h>
  47 #include <asm/processor.h>
  48 #include <asm/cputable.h>
  49 #include <asm/sections.h>
  50 #include <asm/system.h>
  51 #include <asm/abs_addr.h>
  52 #include <asm/firmware.h>
  53
  54 #include "mmu_decl.h"
  55
  56 unsigned long ioremap_bot = IOREMAP_BASE;
  57
  58 /*
  59  * map_io_page currently only called by __ioremap
  60  * map_io_page adds an entry to the ioremap page table
  61  * and adds an entry to the HPT, possibly bolting it
  62  */
  63 static int map_io_page(unsigned long ea, unsigned long pa, int flags)
  64 {
  65         pgd_t *pgdp;
  66         pud_t *pudp;
  67         pmd_t *pmdp;
  68         pte_t *ptep;
  69
  70         if (mem_init_done) {
  71                 pgdp = pgd_offset_k(ea);
  72                 pudp = pud_alloc(&init_mm, pgdp, ea);
  73                 if (!pudp)
  74                         return -ENOMEM;
  75                 pmdp = pmd_alloc(&init_mm, pudp, ea);
  76                 if (!pmdp)
  77                         return -ENOMEM;
  78                 ptep = pte_alloc_kernel(pmdp, ea);
  79                 if (!ptep)
  80                         return -ENOMEM;
  81                 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
  82                                                           __pgprot(flags)));
  83         } else {
  84                 /*
  85                  * If the mm subsystem is not fully up, we cannot create a
  86                  * linux page table entry for this mapping.  Simply bolt an
  87                  * entry in the hardware page table.
  88                  *
  89                  */
  90                 if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags,
  91                                       mmu_io_psize, mmu_kernel_ssize)) {
  92                         printk(KERN_ERR "Failed to do bolted mapping IO "
  93                                "memory at %016lx !\n", pa);
  94                         return -ENOMEM;
  95                 }
  96         }
  97         return 0;
  98 }
  99
 100
 101 /**
 102  * __ioremap_at - Low level function to establish the page tables
 103  *                for an IO mapping
 104  */
 105 void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
 106                             unsigned long flags)
 107 {
 108         unsigned long i;
 109
 110         /* Make sure we have the base flags */
 111         if ((flags & _PAGE_PRESENT) == 0)
 112                 flags |= pgprot_val(PAGE_KERNEL);
 113
 114         /* Non-cacheable page cannot be coherent */
 115         if (flags & _PAGE_NO_CACHE)
 116                 flags &= ~_PAGE_COHERENT;
 117
 118         /* We don't support the 4K PFN hack with ioremap */
 119         if (flags & _PAGE_4K_PFN)
 120                 return NULL;
 121
 122         WARN_ON(pa & ~PAGE_MASK);
 123         WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
 124         WARN_ON(size & ~PAGE_MASK);
 125
 126         for (i = 0; i < size; i += PAGE_SIZE)
 127                 if (map_io_page((unsigned long)ea+i, pa+i, flags))
 128                         return NULL;
 129
 130         return (void __iomem *)ea;
 131 }
 132
 133 /**
 134  * __iounmap_from - Low level function to tear down the page tables
 135  *                  for an IO mapping. This is used for mappings that
 136  *                  are manipulated manually, like partial unmapping of
 137  *                  PCI IOs or ISA space.
 138  */
 139 void __iounmap_at(void *ea, unsigned long size)
 140 {
 141         WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
 142         WARN_ON(size & ~PAGE_MASK);
 143
 144         unmap_kernel_range((unsigned long)ea, size);
 145 }
 146
 147 void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
 148                                 unsigned long flags, void *caller)
 149 {
 150         phys_addr_t paligned;
 151         void __iomem *ret;
 152
 153         /*
 154          * Choose an address to map it to.
 155          * Once the imalloc system is running, we use it.
 156          * Before that, we map using addresses going
 157          * up from ioremap_bot.  imalloc will use
 158          * the addresses from ioremap_bot through
 159          * IMALLOC_END
 160          *
 161          */
 162         paligned = addr & PAGE_MASK;
 163         size = PAGE_ALIGN(addr + size) - paligned;
 164
 165         if ((size == 0) || (paligned == 0))
 166                 return NULL;
 167
 168         if (mem_init_done) {
 169                 struct vm_struct *area;
 170
 171                 area = __get_vm_area_caller(size, VM_IOREMAP,
 172                                             ioremap_bot, IOREMAP_END,
 173                                             caller);
 174                 if (area == NULL)
 175                         return NULL;
 176                 ret = __ioremap_at(paligned, area->addr, size, flags);
 177                 if (!ret)
 178                         vunmap(area->addr);
 179         } else {
 180                 ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
 181                 if (ret)
 182                         ioremap_bot += size;
 183         }
 184
 185         if (ret)
 186                 ret += addr & ~PAGE_MASK;
 187         return ret;
 188 }
 189
 190 void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
 191                          unsigned long flags)
 192 {
 193         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 194 }
 195
 196 void __iomem * ioremap(phys_addr_t addr, unsigned long size)
 197 {
 198         unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;
 199         void *caller = __builtin_return_address(0);
 200
 201         if (ppc_md.ioremap)
 202                 return ppc_md.ioremap(addr, size, flags, caller);
 203         return __ioremap_caller(addr, size, flags, caller);
 204 }
 205
 206 void __iomem * ioremap_flags(phys_addr_t addr, unsigned long size,
 207                              unsigned long flags)
 208 {
 209         void *caller = __builtin_return_address(0);
 210
 211         /* writeable implies dirty for kernel addresses */
 212         if (flags & _PAGE_RW)
 213                 flags |= _PAGE_DIRTY;
 214
 215         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 216         flags &= ~(_PAGE_USER | _PAGE_EXEC);
 217
 218         if (ppc_md.ioremap)
 219                 return ppc_md.ioremap(addr, size, flags, caller);
 220         return __ioremap_caller(addr, size, flags, caller);
 221 }
 222
 223
 224 /*
 225  * Unmap an IO region and remove it from imalloc'd list.
 226  * Access to IO memory should be serialized by driver.
 227  */
 228 void __iounmap(volatile void __iomem *token)
 229 {
 230         void *addr;
 231
 232         if (!mem_init_done)
 233                 return;
 234
 235         addr = (void *) ((unsigned long __force)
 236                          PCI_FIX_ADDR(token) & PAGE_MASK);
 237         if ((unsigned long)addr < ioremap_bot) {
 238                 printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
 239                        " at 0x%p\n", addr);
 240                 return;
 241         }
 242         vunmap(addr);
 243 }
 244
 245 void iounmap(volatile void __iomem *token)
 246 {
 247         if (ppc_md.iounmap)
 248                 ppc_md.iounmap(token);
 249         else
 250                 __iounmap(token);
 251 }
 252
 253 EXPORT_SYMBOL(ioremap);
 254 EXPORT_SYMBOL(ioremap_flags);
 255 EXPORT_SYMBOL(__ioremap);
 256 EXPORT_SYMBOL(__ioremap_at);
 257 EXPORT_SYMBOL(iounmap);
 258 EXPORT_SYMBOL(__iounmap);
 259 EXPORT_SYMBOL(__iounmap_at);