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e7cc9a73 MD |
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> | |
ecc14e8c | 16 | #include <linux/module.h> |
eeee7853 | 17 | #include <linux/init.h> |
e7cc9a73 MD |
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 | |
e7cc9a73 MD |
25 | |
26 | #ifdef CONFIG_HAS_IOPORT | |
27 | LIST_HEAD(trapped_io); | |
ecc14e8c | 28 | EXPORT_SYMBOL_GPL(trapped_io); |
e7cc9a73 MD |
29 | #endif |
30 | #ifdef CONFIG_HAS_IOMEM | |
31 | LIST_HEAD(trapped_mem); | |
ecc14e8c | 32 | EXPORT_SYMBOL_GPL(trapped_mem); |
e7cc9a73 MD |
33 | #endif |
34 | static DEFINE_SPINLOCK(trapped_lock); | |
35 | ||
eeee7853 PM |
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 | ||
b2839ed8 | 45 | int register_trapped_io(struct trapped_io *tiop) |
e7cc9a73 MD |
46 | { |
47 | struct resource *res; | |
48 | unsigned long len = 0, flags = 0; | |
49 | struct page *pages[TRAPPED_PAGES_MAX]; | |
50 | int k, n; | |
51 | ||
eeee7853 PM |
52 | if (unlikely(trapped_io_disable)) |
53 | return 0; | |
54 | ||
e7cc9a73 MD |
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 | } | |
ecc14e8c | 105 | EXPORT_SYMBOL_GPL(register_trapped_io); |
e7cc9a73 MD |
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 | } | |
ecc14e8c | 133 | EXPORT_SYMBOL_GPL(match_trapped_io_handler); |
e7cc9a73 MD |
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 | ||
f1cdd63f PM |
231 | tmp = copy_word(src_addr, |
232 | max_t(unsigned long, cnt, | |
233 | (tiop->minimum_bus_width / 8)), | |
e7cc9a73 MD |
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, | |
f1cdd63f PM |
255 | dst_addr, max_t(unsigned long, cnt, |
256 | (tiop->minimum_bus_width / 8))); | |
e7cc9a73 MD |
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 | opcode_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 | } |