Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 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 <asm/system.h> |
| 17 | #include <asm/mmu_context.h> |
| 18 | #include <asm/uaccess.h> |
| 19 | #include <asm/io.h> |
| 20 | #include <asm/io_trapped.h> |
| 21 | |
| 22 | #define TRAPPED_PAGES_MAX 16 |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 23 | |
| 24 | #ifdef CONFIG_HAS_IOPORT |
| 25 | LIST_HEAD(trapped_io); |
| 26 | #endif |
| 27 | #ifdef CONFIG_HAS_IOMEM |
| 28 | LIST_HEAD(trapped_mem); |
| 29 | #endif |
| 30 | static DEFINE_SPINLOCK(trapped_lock); |
| 31 | |
| 32 | int __init register_trapped_io(struct trapped_io *tiop) |
| 33 | { |
| 34 | struct resource *res; |
| 35 | unsigned long len = 0, flags = 0; |
| 36 | struct page *pages[TRAPPED_PAGES_MAX]; |
| 37 | int k, n; |
| 38 | |
| 39 | /* structure must be page aligned */ |
| 40 | if ((unsigned long)tiop & (PAGE_SIZE - 1)) |
| 41 | goto bad; |
| 42 | |
| 43 | for (k = 0; k < tiop->num_resources; k++) { |
| 44 | res = tiop->resource + k; |
| 45 | len += roundup((res->end - res->start) + 1, PAGE_SIZE); |
| 46 | flags |= res->flags; |
| 47 | } |
| 48 | |
| 49 | /* support IORESOURCE_IO _or_ MEM, not both */ |
| 50 | if (hweight_long(flags) != 1) |
| 51 | goto bad; |
| 52 | |
| 53 | n = len >> PAGE_SHIFT; |
| 54 | |
| 55 | if (n >= TRAPPED_PAGES_MAX) |
| 56 | goto bad; |
| 57 | |
| 58 | for (k = 0; k < n; k++) |
| 59 | pages[k] = virt_to_page(tiop); |
| 60 | |
| 61 | tiop->virt_base = vmap(pages, n, VM_MAP, PAGE_NONE); |
| 62 | if (!tiop->virt_base) |
| 63 | goto bad; |
| 64 | |
| 65 | len = 0; |
| 66 | for (k = 0; k < tiop->num_resources; k++) { |
| 67 | res = tiop->resource + k; |
| 68 | pr_info("trapped io 0x%08lx overrides %s 0x%08lx\n", |
| 69 | (unsigned long)(tiop->virt_base + len), |
| 70 | res->flags & IORESOURCE_IO ? "io" : "mmio", |
| 71 | (unsigned long)res->start); |
| 72 | len += roundup((res->end - res->start) + 1, PAGE_SIZE); |
| 73 | } |
| 74 | |
| 75 | tiop->magic = IO_TRAPPED_MAGIC; |
| 76 | INIT_LIST_HEAD(&tiop->list); |
| 77 | spin_lock_irq(&trapped_lock); |
| 78 | if (flags & IORESOURCE_IO) |
| 79 | list_add(&tiop->list, &trapped_io); |
| 80 | if (flags & IORESOURCE_MEM) |
| 81 | list_add(&tiop->list, &trapped_mem); |
| 82 | spin_unlock_irq(&trapped_lock); |
| 83 | |
| 84 | return 0; |
| 85 | bad: |
| 86 | pr_warning("unable to install trapped io filter\n"); |
| 87 | return -1; |
| 88 | } |
| 89 | |
| 90 | void __iomem *match_trapped_io_handler(struct list_head *list, |
| 91 | unsigned long offset, |
| 92 | unsigned long size) |
| 93 | { |
| 94 | unsigned long voffs; |
| 95 | struct trapped_io *tiop; |
| 96 | struct resource *res; |
| 97 | int k, len; |
| 98 | |
| 99 | spin_lock_irq(&trapped_lock); |
| 100 | list_for_each_entry(tiop, list, list) { |
| 101 | voffs = 0; |
| 102 | for (k = 0; k < tiop->num_resources; k++) { |
| 103 | res = tiop->resource + k; |
| 104 | if (res->start == offset) { |
| 105 | spin_unlock_irq(&trapped_lock); |
| 106 | return tiop->virt_base + voffs; |
| 107 | } |
| 108 | |
| 109 | len = (res->end - res->start) + 1; |
| 110 | voffs += roundup(len, PAGE_SIZE); |
| 111 | } |
| 112 | } |
| 113 | spin_unlock_irq(&trapped_lock); |
| 114 | return NULL; |
| 115 | } |
| 116 | |
| 117 | static struct trapped_io *lookup_tiop(unsigned long address) |
| 118 | { |
| 119 | pgd_t *pgd_k; |
| 120 | pud_t *pud_k; |
| 121 | pmd_t *pmd_k; |
| 122 | pte_t *pte_k; |
| 123 | pte_t entry; |
| 124 | |
| 125 | pgd_k = swapper_pg_dir + pgd_index(address); |
| 126 | if (!pgd_present(*pgd_k)) |
| 127 | return NULL; |
| 128 | |
| 129 | pud_k = pud_offset(pgd_k, address); |
| 130 | if (!pud_present(*pud_k)) |
| 131 | return NULL; |
| 132 | |
| 133 | pmd_k = pmd_offset(pud_k, address); |
| 134 | if (!pmd_present(*pmd_k)) |
| 135 | return NULL; |
| 136 | |
| 137 | pte_k = pte_offset_kernel(pmd_k, address); |
| 138 | entry = *pte_k; |
| 139 | |
| 140 | return pfn_to_kaddr(pte_pfn(entry)); |
| 141 | } |
| 142 | |
| 143 | static unsigned long lookup_address(struct trapped_io *tiop, |
| 144 | unsigned long address) |
| 145 | { |
| 146 | struct resource *res; |
| 147 | unsigned long vaddr = (unsigned long)tiop->virt_base; |
| 148 | unsigned long len; |
| 149 | int k; |
| 150 | |
| 151 | for (k = 0; k < tiop->num_resources; k++) { |
| 152 | res = tiop->resource + k; |
| 153 | len = roundup((res->end - res->start) + 1, PAGE_SIZE); |
| 154 | if (address < (vaddr + len)) |
| 155 | return res->start + (address - vaddr); |
| 156 | vaddr += len; |
| 157 | } |
| 158 | return 0; |
| 159 | } |
| 160 | |
| 161 | static unsigned long long copy_word(unsigned long src_addr, int src_len, |
| 162 | unsigned long dst_addr, int dst_len) |
| 163 | { |
| 164 | unsigned long long tmp = 0; |
| 165 | |
| 166 | switch (src_len) { |
| 167 | case 1: |
| 168 | tmp = ctrl_inb(src_addr); |
| 169 | break; |
| 170 | case 2: |
| 171 | tmp = ctrl_inw(src_addr); |
| 172 | break; |
| 173 | case 4: |
| 174 | tmp = ctrl_inl(src_addr); |
| 175 | break; |
| 176 | case 8: |
| 177 | tmp = ctrl_inq(src_addr); |
| 178 | break; |
| 179 | } |
| 180 | |
| 181 | switch (dst_len) { |
| 182 | case 1: |
| 183 | ctrl_outb(tmp, dst_addr); |
| 184 | break; |
| 185 | case 2: |
| 186 | ctrl_outw(tmp, dst_addr); |
| 187 | break; |
| 188 | case 4: |
| 189 | ctrl_outl(tmp, dst_addr); |
| 190 | break; |
| 191 | case 8: |
| 192 | ctrl_outq(tmp, dst_addr); |
| 193 | break; |
| 194 | } |
| 195 | |
| 196 | return tmp; |
| 197 | } |
| 198 | |
| 199 | static unsigned long from_device(void *dst, const void *src, unsigned long cnt) |
| 200 | { |
| 201 | struct trapped_io *tiop; |
| 202 | unsigned long src_addr = (unsigned long)src; |
| 203 | unsigned long long tmp; |
| 204 | |
| 205 | pr_debug("trapped io read 0x%08lx (%ld)\n", src_addr, cnt); |
| 206 | tiop = lookup_tiop(src_addr); |
| 207 | WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC)); |
| 208 | |
| 209 | src_addr = lookup_address(tiop, src_addr); |
| 210 | if (!src_addr) |
| 211 | return cnt; |
| 212 | |
Paul Mundt | f1cdd63 | 2008-02-09 19:10:52 +0900 | [diff] [blame^] | 213 | tmp = copy_word(src_addr, |
| 214 | max_t(unsigned long, cnt, |
| 215 | (tiop->minimum_bus_width / 8)), |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 216 | (unsigned long)dst, cnt); |
| 217 | |
| 218 | pr_debug("trapped io read 0x%08lx -> 0x%08llx\n", src_addr, tmp); |
| 219 | return 0; |
| 220 | } |
| 221 | |
| 222 | static unsigned long to_device(void *dst, const void *src, unsigned long cnt) |
| 223 | { |
| 224 | struct trapped_io *tiop; |
| 225 | unsigned long dst_addr = (unsigned long)dst; |
| 226 | unsigned long long tmp; |
| 227 | |
| 228 | pr_debug("trapped io write 0x%08lx (%ld)\n", dst_addr, cnt); |
| 229 | tiop = lookup_tiop(dst_addr); |
| 230 | WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC)); |
| 231 | |
| 232 | dst_addr = lookup_address(tiop, dst_addr); |
| 233 | if (!dst_addr) |
| 234 | return cnt; |
| 235 | |
| 236 | tmp = copy_word((unsigned long)src, cnt, |
Paul Mundt | f1cdd63 | 2008-02-09 19:10:52 +0900 | [diff] [blame^] | 237 | dst_addr, max_t(unsigned long, cnt, |
| 238 | (tiop->minimum_bus_width / 8))); |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 239 | |
| 240 | pr_debug("trapped io write 0x%08lx -> 0x%08llx\n", dst_addr, tmp); |
| 241 | return 0; |
| 242 | } |
| 243 | |
| 244 | static struct mem_access trapped_io_access = { |
| 245 | from_device, |
| 246 | to_device, |
| 247 | }; |
| 248 | |
| 249 | int handle_trapped_io(struct pt_regs *regs, unsigned long address) |
| 250 | { |
| 251 | mm_segment_t oldfs; |
| 252 | opcode_t instruction; |
| 253 | int tmp; |
| 254 | |
| 255 | if (!lookup_tiop(address)) |
| 256 | return 0; |
| 257 | |
| 258 | WARN_ON(user_mode(regs)); |
| 259 | |
| 260 | oldfs = get_fs(); |
| 261 | set_fs(KERNEL_DS); |
| 262 | if (copy_from_user(&instruction, (void *)(regs->pc), |
| 263 | sizeof(instruction))) { |
| 264 | set_fs(oldfs); |
| 265 | return 0; |
| 266 | } |
| 267 | |
| 268 | tmp = handle_unaligned_access(instruction, regs, &trapped_io_access); |
| 269 | set_fs(oldfs); |
| 270 | return tmp == 0; |
| 271 | } |