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> |
Paul Mundt | ecc14e8 | 2008-02-12 16:02:02 +0900 | [diff] [blame] | 16 | #include <linux/module.h> |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 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 |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 24 | |
| 25 | #ifdef CONFIG_HAS_IOPORT |
| 26 | LIST_HEAD(trapped_io); |
Paul Mundt | ecc14e8 | 2008-02-12 16:02:02 +0900 | [diff] [blame] | 27 | EXPORT_SYMBOL_GPL(trapped_io); |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 28 | #endif |
| 29 | #ifdef CONFIG_HAS_IOMEM |
| 30 | LIST_HEAD(trapped_mem); |
Paul Mundt | ecc14e8 | 2008-02-12 16:02:02 +0900 | [diff] [blame] | 31 | EXPORT_SYMBOL_GPL(trapped_mem); |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 32 | #endif |
| 33 | static DEFINE_SPINLOCK(trapped_lock); |
| 34 | |
Paul Mundt | b2839ed | 2008-03-06 12:43:38 +0900 | [diff] [blame^] | 35 | int register_trapped_io(struct trapped_io *tiop) |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 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 | } |
Paul Mundt | ecc14e8 | 2008-02-12 16:02:02 +0900 | [diff] [blame] | 92 | EXPORT_SYMBOL_GPL(register_trapped_io); |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 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 | } |
Paul Mundt | ecc14e8 | 2008-02-12 16:02:02 +0900 | [diff] [blame] | 120 | EXPORT_SYMBOL_GPL(match_trapped_io_handler); |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 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 | |
Paul Mundt | f1cdd63 | 2008-02-09 19:10:52 +0900 | [diff] [blame] | 218 | tmp = copy_word(src_addr, |
| 219 | max_t(unsigned long, cnt, |
| 220 | (tiop->minimum_bus_width / 8)), |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 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, |
Paul Mundt | f1cdd63 | 2008-02-09 19:10:52 +0900 | [diff] [blame] | 242 | dst_addr, max_t(unsigned long, cnt, |
| 243 | (tiop->minimum_bus_width / 8))); |
Magnus Damm | e7cc9a7 | 2008-02-07 20:18:21 +0900 | [diff] [blame] | 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 | } |