4 * Copyright (C) 2008 Magnus Damm
6 * Intercept io operations by trapping.
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
12 #include <linux/kernel.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>
22 #include <asm/io_trapped.h>
24 #define TRAPPED_PAGES_MAX 16
26 #ifdef CONFIG_HAS_IOPORT
27 LIST_HEAD(trapped_io);
28 EXPORT_SYMBOL_GPL(trapped_io);
30 #ifdef CONFIG_HAS_IOMEM
31 LIST_HEAD(trapped_mem);
32 EXPORT_SYMBOL_GPL(trapped_mem);
34 static DEFINE_SPINLOCK(trapped_lock);
36 static int trapped_io_disable __read_mostly;
38 static int __init trapped_io_setup(char *__unused)
40 trapped_io_disable = 1;
43 __setup("noiotrap", trapped_io_setup);
45 int register_trapped_io(struct trapped_io *tiop)
48 unsigned long len = 0, flags = 0;
49 struct page *pages[TRAPPED_PAGES_MAX];
52 if (unlikely(trapped_io_disable))
55 /* structure must be page aligned */
56 if ((unsigned long)tiop & (PAGE_SIZE - 1))
59 for (k = 0; k < tiop->num_resources; k++) {
60 res = tiop->resource + k;
61 len += roundup((res->end - res->start) + 1, PAGE_SIZE);
65 /* support IORESOURCE_IO _or_ MEM, not both */
66 if (hweight_long(flags) != 1)
69 n = len >> PAGE_SHIFT;
71 if (n >= TRAPPED_PAGES_MAX)
74 for (k = 0; k < n; k++)
75 pages[k] = virt_to_page(tiop);
77 tiop->virt_base = vmap(pages, n, VM_MAP, PAGE_NONE);
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);
91 tiop->magic = IO_TRAPPED_MAGIC;
92 INIT_LIST_HEAD(&tiop->list);
93 spin_lock_irq(&trapped_lock);
94 #ifdef CONFIG_HAS_IOPORT
95 if (flags & IORESOURCE_IO)
96 list_add(&tiop->list, &trapped_io);
98 #ifdef CONFIG_HAS_IOMEM
99 if (flags & IORESOURCE_MEM)
100 list_add(&tiop->list, &trapped_mem);
102 spin_unlock_irq(&trapped_lock);
106 pr_warning("unable to install trapped io filter\n");
109 EXPORT_SYMBOL_GPL(register_trapped_io);
111 void __iomem *match_trapped_io_handler(struct list_head *list,
112 unsigned long offset,
116 struct trapped_io *tiop;
117 struct resource *res;
121 spin_lock_irqsave(&trapped_lock, flags);
122 list_for_each_entry(tiop, list, list) {
124 for (k = 0; k < tiop->num_resources; k++) {
125 res = tiop->resource + k;
126 if (res->start == offset) {
127 spin_unlock_irqrestore(&trapped_lock, flags);
128 return tiop->virt_base + voffs;
131 len = (res->end - res->start) + 1;
132 voffs += roundup(len, PAGE_SIZE);
135 spin_unlock_irqrestore(&trapped_lock, flags);
138 EXPORT_SYMBOL_GPL(match_trapped_io_handler);
140 static struct trapped_io *lookup_tiop(unsigned long address)
148 pgd_k = swapper_pg_dir + pgd_index(address);
149 if (!pgd_present(*pgd_k))
152 pud_k = pud_offset(pgd_k, address);
153 if (!pud_present(*pud_k))
156 pmd_k = pmd_offset(pud_k, address);
157 if (!pmd_present(*pmd_k))
160 pte_k = pte_offset_kernel(pmd_k, address);
163 return pfn_to_kaddr(pte_pfn(entry));
166 static unsigned long lookup_address(struct trapped_io *tiop,
167 unsigned long address)
169 struct resource *res;
170 unsigned long vaddr = (unsigned long)tiop->virt_base;
174 for (k = 0; k < tiop->num_resources; k++) {
175 res = tiop->resource + k;
176 len = roundup((res->end - res->start) + 1, PAGE_SIZE);
177 if (address < (vaddr + len))
178 return res->start + (address - vaddr);
184 static unsigned long long copy_word(unsigned long src_addr, int src_len,
185 unsigned long dst_addr, int dst_len)
187 unsigned long long tmp = 0;
191 tmp = __raw_readb(src_addr);
194 tmp = __raw_readw(src_addr);
197 tmp = __raw_readl(src_addr);
200 tmp = __raw_readq(src_addr);
206 __raw_writeb(tmp, dst_addr);
209 __raw_writew(tmp, dst_addr);
212 __raw_writel(tmp, dst_addr);
215 __raw_writeq(tmp, dst_addr);
222 static unsigned long from_device(void *dst, const void *src, unsigned long cnt)
224 struct trapped_io *tiop;
225 unsigned long src_addr = (unsigned long)src;
226 unsigned long long tmp;
228 pr_debug("trapped io read 0x%08lx (%ld)\n", src_addr, cnt);
229 tiop = lookup_tiop(src_addr);
230 WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
232 src_addr = lookup_address(tiop, src_addr);
236 tmp = copy_word(src_addr,
237 max_t(unsigned long, cnt,
238 (tiop->minimum_bus_width / 8)),
239 (unsigned long)dst, cnt);
241 pr_debug("trapped io read 0x%08lx -> 0x%08llx\n", src_addr, tmp);
245 static unsigned long to_device(void *dst, const void *src, unsigned long cnt)
247 struct trapped_io *tiop;
248 unsigned long dst_addr = (unsigned long)dst;
249 unsigned long long tmp;
251 pr_debug("trapped io write 0x%08lx (%ld)\n", dst_addr, cnt);
252 tiop = lookup_tiop(dst_addr);
253 WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
255 dst_addr = lookup_address(tiop, dst_addr);
259 tmp = copy_word((unsigned long)src, cnt,
260 dst_addr, max_t(unsigned long, cnt,
261 (tiop->minimum_bus_width / 8)));
263 pr_debug("trapped io write 0x%08lx -> 0x%08llx\n", dst_addr, tmp);
267 static struct mem_access trapped_io_access = {
272 int handle_trapped_io(struct pt_regs *regs, unsigned long address)
275 insn_size_t instruction;
278 if (trapped_io_disable)
280 if (!lookup_tiop(address))
283 WARN_ON(user_mode(regs));
287 if (copy_from_user(&instruction, (void *)(regs->pc),
288 sizeof(instruction))) {
293 tmp = handle_unaligned_access(instruction, regs,
294 &trapped_io_access, 1);