Merge branch 'core/xen' into x86/xen
[linux-2.6] / 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 }