arch/sh/kernel/io_trapped.c

   1 /*
   2  * Trapped io support
   3  *
   4  * Copyright (C) 2008 Magnus Damm
   5  *
   6  * Intercept io operations by trapping.
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/mm.h>
  14 #include <linux/bitops.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/module.h>
  17 #include <asm/system.h>
  18 #include <asm/mmu_context.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/io.h>
  21 #include <asm/io_trapped.h>
  22
  23 #define TRAPPED_PAGES_MAX 16
  24
  25 #ifdef CONFIG_HAS_IOPORT
  26 LIST_HEAD(trapped_io);
  27 EXPORT_SYMBOL_GPL(trapped_io);
  28 #endif
  29 #ifdef CONFIG_HAS_IOMEM
  30 LIST_HEAD(trapped_mem);
  31 EXPORT_SYMBOL_GPL(trapped_mem);
  32 #endif
  33 static DEFINE_SPINLOCK(trapped_lock);
  34
  35 int register_trapped_io(struct trapped_io *tiop)
  36 {
  37         struct resource *res;
  38         unsigned long len = 0, flags = 0;
  39         struct page *pages[TRAPPED_PAGES_MAX];
  40         int k, n;
  41
  42         /* structure must be page aligned */
  43         if ((unsigned long)tiop & (PAGE_SIZE - 1))
  44                 goto bad;
  45
  46         for (k = 0; k < tiop->num_resources; k++) {
  47                 res = tiop->resource + k;
  48                 len += roundup((res->end - res->start) + 1, PAGE_SIZE);
  49                 flags |= res->flags;
  50         }
  51
  52         /* support IORESOURCE_IO _or_ MEM, not both */
  53         if (hweight_long(flags) != 1)
  54                 goto bad;
  55
  56         n = len >> PAGE_SHIFT;
  57
  58         if (n >= TRAPPED_PAGES_MAX)
  59                 goto bad;
  60
  61         for (k = 0; k < n; k++)
  62                 pages[k] = virt_to_page(tiop);
  63
  64         tiop->virt_base = vmap(pages, n, VM_MAP, PAGE_NONE);
  65         if (!tiop->virt_base)
  66                 goto bad;
  67
  68         len = 0;
  69         for (k = 0; k < tiop->num_resources; k++) {
  70                 res = tiop->resource + k;
  71                 pr_info("trapped io 0x%08lx overrides %s 0x%08lx\n",
  72                        (unsigned long)(tiop->virt_base + len),
  73                        res->flags & IORESOURCE_IO ? "io" : "mmio",
  74                        (unsigned long)res->start);
  75                 len += roundup((res->end - res->start) + 1, PAGE_SIZE);
  76         }
  77
  78         tiop->magic = IO_TRAPPED_MAGIC;
  79         INIT_LIST_HEAD(&tiop->list);
  80         spin_lock_irq(&trapped_lock);
  81         if (flags & IORESOURCE_IO)
  82                 list_add(&tiop->list, &trapped_io);
  83         if (flags & IORESOURCE_MEM)
  84                 list_add(&tiop->list, &trapped_mem);
  85         spin_unlock_irq(&trapped_lock);
  86
  87         return 0;
  88  bad:
  89         pr_warning("unable to install trapped io filter\n");
  90         return -1;
  91 }
  92 EXPORT_SYMBOL_GPL(register_trapped_io);
  93
  94 void __iomem *match_trapped_io_handler(struct list_head *list,
  95                                        unsigned long offset,
  96                                        unsigned long size)
  97 {
  98         unsigned long voffs;
  99         struct trapped_io *tiop;
 100         struct resource *res;
 101         int k, len;
 102
 103         spin_lock_irq(&trapped_lock);
 104         list_for_each_entry(tiop, list, list) {
 105                 voffs = 0;
 106                 for (k = 0; k < tiop->num_resources; k++) {
 107                         res = tiop->resource + k;
 108                         if (res->start == offset) {
 109                                 spin_unlock_irq(&trapped_lock);
 110                                 return tiop->virt_base + voffs;
 111                         }
 112
 113                         len = (res->end - res->start) + 1;
 114                         voffs += roundup(len, PAGE_SIZE);
 115                 }
 116         }
 117         spin_unlock_irq(&trapped_lock);
 118         return NULL;
 119 }
 120 EXPORT_SYMBOL_GPL(match_trapped_io_handler);
 121
 122 static struct trapped_io *lookup_tiop(unsigned long address)
 123 {
 124         pgd_t *pgd_k;
 125         pud_t *pud_k;
 126         pmd_t *pmd_k;
 127         pte_t *pte_k;
 128         pte_t entry;
 129
 130         pgd_k = swapper_pg_dir + pgd_index(address);
 131         if (!pgd_present(*pgd_k))
 132                 return NULL;
 133
 134         pud_k = pud_offset(pgd_k, address);
 135         if (!pud_present(*pud_k))
 136                 return NULL;
 137
 138         pmd_k = pmd_offset(pud_k, address);
 139         if (!pmd_present(*pmd_k))
 140                 return NULL;
 141
 142         pte_k = pte_offset_kernel(pmd_k, address);
 143         entry = *pte_k;
 144
 145         return pfn_to_kaddr(pte_pfn(entry));
 146 }
 147
 148 static unsigned long lookup_address(struct trapped_io *tiop,
 149                                     unsigned long address)
 150 {
 151         struct resource *res;
 152         unsigned long vaddr = (unsigned long)tiop->virt_base;
 153         unsigned long len;
 154         int k;
 155
 156         for (k = 0; k < tiop->num_resources; k++) {
 157                 res = tiop->resource + k;
 158                 len = roundup((res->end - res->start) + 1, PAGE_SIZE);
 159                 if (address < (vaddr + len))
 160                         return res->start + (address - vaddr);
 161                 vaddr += len;
 162         }
 163         return 0;
 164 }
 165
 166 static unsigned long long copy_word(unsigned long src_addr, int src_len,
 167                                     unsigned long dst_addr, int dst_len)
 168 {
 169         unsigned long long tmp = 0;
 170
 171         switch (src_len) {
 172         case 1:
 173                 tmp = ctrl_inb(src_addr);
 174                 break;
 175         case 2:
 176                 tmp = ctrl_inw(src_addr);
 177                 break;
 178         case 4:
 179                 tmp = ctrl_inl(src_addr);
 180                 break;
 181         case 8:
 182                 tmp = ctrl_inq(src_addr);
 183                 break;
 184         }
 185
 186         switch (dst_len) {
 187         case 1:
 188                 ctrl_outb(tmp, dst_addr);
 189                 break;
 190         case 2:
 191                 ctrl_outw(tmp, dst_addr);
 192                 break;
 193         case 4:
 194                 ctrl_outl(tmp, dst_addr);
 195                 break;
 196         case 8:
 197                 ctrl_outq(tmp, dst_addr);
 198                 break;
 199         }
 200
 201         return tmp;
 202 }
 203
 204 static unsigned long from_device(void *dst, const void *src, unsigned long cnt)
 205 {
 206         struct trapped_io *tiop;
 207         unsigned long src_addr = (unsigned long)src;
 208         unsigned long long tmp;
 209
 210         pr_debug("trapped io read 0x%08lx (%ld)\n", src_addr, cnt);
 211         tiop = lookup_tiop(src_addr);
 212         WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
 213
 214         src_addr = lookup_address(tiop, src_addr);
 215         if (!src_addr)
 216                 return cnt;
 217
 218         tmp = copy_word(src_addr,
 219                         max_t(unsigned long, cnt,
 220                               (tiop->minimum_bus_width / 8)),
 221                         (unsigned long)dst, cnt);
 222
 223         pr_debug("trapped io read 0x%08lx -> 0x%08llx\n", src_addr, tmp);
 224         return 0;
 225 }
 226
 227 static unsigned long to_device(void *dst, const void *src, unsigned long cnt)
 228 {
 229         struct trapped_io *tiop;
 230         unsigned long dst_addr = (unsigned long)dst;
 231         unsigned long long tmp;
 232
 233         pr_debug("trapped io write 0x%08lx (%ld)\n", dst_addr, cnt);
 234         tiop = lookup_tiop(dst_addr);
 235         WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
 236
 237         dst_addr = lookup_address(tiop, dst_addr);
 238         if (!dst_addr)
 239                 return cnt;
 240
 241         tmp = copy_word((unsigned long)src, cnt,
 242                         dst_addr, max_t(unsigned long, cnt,
 243                                         (tiop->minimum_bus_width / 8)));
 244
 245         pr_debug("trapped io write 0x%08lx -> 0x%08llx\n", dst_addr, tmp);
 246         return 0;
 247 }
 248
 249 static struct mem_access trapped_io_access = {
 250         from_device,
 251         to_device,
 252 };
 253
 254 int handle_trapped_io(struct pt_regs *regs, unsigned long address)
 255 {
 256         mm_segment_t oldfs;
 257         opcode_t instruction;
 258         int tmp;
 259
 260         if (!lookup_tiop(address))
 261                 return 0;
 262
 263         WARN_ON(user_mode(regs));
 264
 265         oldfs = get_fs();
 266         set_fs(KERNEL_DS);
 267         if (copy_from_user(&instruction, (void *)(regs->pc),
 268                            sizeof(instruction))) {
 269                 set_fs(oldfs);
 270                 return 0;
 271         }
 272
 273         tmp = handle_unaligned_access(instruction, regs, &trapped_io_access);
 274         set_fs(oldfs);
 275         return tmp == 0;
 276 }