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 <linux/init.h>
  18 #include <asm/system.h>
  19 #include <asm/mmu_context.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/io.h>
  22 #include <asm/io_trapped.h>
  23
  24 #define TRAPPED_PAGES_MAX 16
  25
  26 #ifdef CONFIG_HAS_IOPORT
  27 LIST_HEAD(trapped_io);
  28 EXPORT_SYMBOL_GPL(trapped_io);
  29 #endif
  30 #ifdef CONFIG_HAS_IOMEM
  31 LIST_HEAD(trapped_mem);
  32 EXPORT_SYMBOL_GPL(trapped_mem);
  33 #endif
  34 static DEFINE_SPINLOCK(trapped_lock);
  35
  36 static int trapped_io_disable __read_mostly;
  37
  38 static int __init trapped_io_setup(char *__unused)
  39 {
  40         trapped_io_disable = 1;
  41         return 1;
  42 }
  43 __setup("noiotrap", trapped_io_setup);
  44
  45 int register_trapped_io(struct trapped_io *tiop)
  46 {
  47         struct resource *res;
  48         unsigned long len = 0, flags = 0;
  49         struct page *pages[TRAPPED_PAGES_MAX];
  50         int k, n;
  51
  52         if (unlikely(trapped_io_disable))
  53                 return 0;
  54
  55         /* structure must be page aligned */
  56         if ((unsigned long)tiop & (PAGE_SIZE - 1))
  57                 goto bad;
  58
  59         for (k = 0; k < tiop->num_resources; k++) {
  60                 res = tiop->resource + k;
  61                 len += roundup((res->end - res->start) + 1, PAGE_SIZE);
  62                 flags |= res->flags;
  63         }
  64
  65         /* support IORESOURCE_IO _or_ MEM, not both */
  66         if (hweight_long(flags) != 1)
  67                 goto bad;
  68
  69         n = len >> PAGE_SHIFT;
  70
  71         if (n >= TRAPPED_PAGES_MAX)
  72                 goto bad;
  73
  74         for (k = 0; k < n; k++)
  75                 pages[k] = virt_to_page(tiop);
  76
  77         tiop->virt_base = vmap(pages, n, VM_MAP, PAGE_NONE);
  78         if (!tiop->virt_base)
  79                 goto bad;
  80
  81         len = 0;
  82         for (k = 0; k < tiop->num_resources; k++) {
  83                 res = tiop->resource + k;
  84                 pr_info("trapped io 0x%08lx overrides %s 0x%08lx\n",
  85                        (unsigned long)(tiop->virt_base + len),
  86                        res->flags & IORESOURCE_IO ? "io" : "mmio",
  87                        (unsigned long)res->start);
  88                 len += roundup((res->end - res->start) + 1, PAGE_SIZE);
  89         }
  90
  91         tiop->magic = IO_TRAPPED_MAGIC;
  92         INIT_LIST_HEAD(&tiop->list);
  93         spin_lock_irq(&trapped_lock);
  94         if (flags & IORESOURCE_IO)
  95                 list_add(&tiop->list, &trapped_io);
  96         if (flags & IORESOURCE_MEM)
  97                 list_add(&tiop->list, &trapped_mem);
  98         spin_unlock_irq(&trapped_lock);
  99
 100         return 0;
 101  bad:
 102         pr_warning("unable to install trapped io filter\n");
 103         return -1;
 104 }
 105 EXPORT_SYMBOL_GPL(register_trapped_io);
 106
 107 void __iomem *match_trapped_io_handler(struct list_head *list,
 108                                        unsigned long offset,
 109                                        unsigned long size)
 110 {
 111         unsigned long voffs;
 112         struct trapped_io *tiop;
 113         struct resource *res;
 114         int k, len;
 115
 116         spin_lock_irq(&trapped_lock);
 117         list_for_each_entry(tiop, list, list) {
 118                 voffs = 0;
 119                 for (k = 0; k < tiop->num_resources; k++) {
 120                         res = tiop->resource + k;
 121                         if (res->start == offset) {
 122                                 spin_unlock_irq(&trapped_lock);
 123                                 return tiop->virt_base + voffs;
 124                         }
 125
 126                         len = (res->end - res->start) + 1;
 127                         voffs += roundup(len, PAGE_SIZE);
 128                 }
 129         }
 130         spin_unlock_irq(&trapped_lock);
 131         return NULL;
 132 }
 133 EXPORT_SYMBOL_GPL(match_trapped_io_handler);
 134
 135 static struct trapped_io *lookup_tiop(unsigned long address)
 136 {
 137         pgd_t *pgd_k;
 138         pud_t *pud_k;
 139         pmd_t *pmd_k;
 140         pte_t *pte_k;
 141         pte_t entry;
 142
 143         pgd_k = swapper_pg_dir + pgd_index(address);
 144         if (!pgd_present(*pgd_k))
 145                 return NULL;
 146
 147         pud_k = pud_offset(pgd_k, address);
 148         if (!pud_present(*pud_k))
 149                 return NULL;
 150
 151         pmd_k = pmd_offset(pud_k, address);
 152         if (!pmd_present(*pmd_k))
 153                 return NULL;
 154
 155         pte_k = pte_offset_kernel(pmd_k, address);
 156         entry = *pte_k;
 157
 158         return pfn_to_kaddr(pte_pfn(entry));
 159 }
 160
 161 static unsigned long lookup_address(struct trapped_io *tiop,
 162                                     unsigned long address)
 163 {
 164         struct resource *res;
 165         unsigned long vaddr = (unsigned long)tiop->virt_base;
 166         unsigned long len;
 167         int k;
 168
 169         for (k = 0; k < tiop->num_resources; k++) {
 170                 res = tiop->resource + k;
 171                 len = roundup((res->end - res->start) + 1, PAGE_SIZE);
 172                 if (address < (vaddr + len))
 173                         return res->start + (address - vaddr);
 174                 vaddr += len;
 175         }
 176         return 0;
 177 }
 178
 179 static unsigned long long copy_word(unsigned long src_addr, int src_len,
 180                                     unsigned long dst_addr, int dst_len)
 181 {
 182         unsigned long long tmp = 0;
 183
 184         switch (src_len) {
 185         case 1:
 186                 tmp = ctrl_inb(src_addr);
 187                 break;
 188         case 2:
 189                 tmp = ctrl_inw(src_addr);
 190                 break;
 191         case 4:
 192                 tmp = ctrl_inl(src_addr);
 193                 break;
 194         case 8:
 195                 tmp = ctrl_inq(src_addr);
 196                 break;
 197         }
 198
 199         switch (dst_len) {
 200         case 1:
 201                 ctrl_outb(tmp, dst_addr);
 202                 break;
 203         case 2:
 204                 ctrl_outw(tmp, dst_addr);
 205                 break;
 206         case 4:
 207                 ctrl_outl(tmp, dst_addr);
 208                 break;
 209         case 8:
 210                 ctrl_outq(tmp, dst_addr);
 211                 break;
 212         }
 213
 214         return tmp;
 215 }
 216
 217 static unsigned long from_device(void *dst, const void *src, unsigned long cnt)
 218 {
 219         struct trapped_io *tiop;
 220         unsigned long src_addr = (unsigned long)src;
 221         unsigned long long tmp;
 222
 223         pr_debug("trapped io read 0x%08lx (%ld)\n", src_addr, cnt);
 224         tiop = lookup_tiop(src_addr);
 225         WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
 226
 227         src_addr = lookup_address(tiop, src_addr);
 228         if (!src_addr)
 229                 return cnt;
 230
 231         tmp = copy_word(src_addr,
 232                         max_t(unsigned long, cnt,
 233                               (tiop->minimum_bus_width / 8)),
 234                         (unsigned long)dst, cnt);
 235
 236         pr_debug("trapped io read 0x%08lx -> 0x%08llx\n", src_addr, tmp);
 237         return 0;
 238 }
 239
 240 static unsigned long to_device(void *dst, const void *src, unsigned long cnt)
 241 {
 242         struct trapped_io *tiop;
 243         unsigned long dst_addr = (unsigned long)dst;
 244         unsigned long long tmp;
 245
 246         pr_debug("trapped io write 0x%08lx (%ld)\n", dst_addr, cnt);
 247         tiop = lookup_tiop(dst_addr);
 248         WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
 249
 250         dst_addr = lookup_address(tiop, dst_addr);
 251         if (!dst_addr)
 252                 return cnt;
 253
 254         tmp = copy_word((unsigned long)src, cnt,
 255                         dst_addr, max_t(unsigned long, cnt,
 256                                         (tiop->minimum_bus_width / 8)));
 257
 258         pr_debug("trapped io write 0x%08lx -> 0x%08llx\n", dst_addr, tmp);
 259         return 0;
 260 }
 261
 262 static struct mem_access trapped_io_access = {
 263         from_device,
 264         to_device,
 265 };
 266
 267 int handle_trapped_io(struct pt_regs *regs, unsigned long address)
 268 {
 269         mm_segment_t oldfs;
 270         insn_size_t instruction;
 271         int tmp;
 272
 273         if (!lookup_tiop(address))
 274                 return 0;
 275
 276         WARN_ON(user_mode(regs));
 277
 278         oldfs = get_fs();
 279         set_fs(KERNEL_DS);
 280         if (copy_from_user(&instruction, (void *)(regs->pc),
 281                            sizeof(instruction))) {
 282                 set_fs(oldfs);
 283                 return 0;
 284         }
 285
 286         tmp = handle_unaligned_access(instruction, regs, &trapped_io_access);
 287         set_fs(oldfs);
 288         return tmp == 0;
 289 }