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 <linux/init.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_MAP
 26LIST_HEAD(trapped_io);
 27EXPORT_SYMBOL_GPL(trapped_io);
 28#endif
 29#ifdef CONFIG_HAS_IOMEM
 30LIST_HEAD(trapped_mem);
 31EXPORT_SYMBOL_GPL(trapped_mem);
 32#endif
 33static DEFINE_SPINLOCK(trapped_lock);
 34
 35static int trapped_io_disable __read_mostly;
 36
 37static int __init trapped_io_setup(char *__unused)
 38{
 39	trapped_io_disable = 1;
 40	return 1;
 41}
 42__setup("noiotrap", trapped_io_setup);
 43
 44int register_trapped_io(struct trapped_io *tiop)
 45{
 46	struct resource *res;
 47	unsigned long len = 0, flags = 0;
 48	struct page *pages[TRAPPED_PAGES_MAX];
 49	int k, n;
 50
 51	if (unlikely(trapped_io_disable))
 52		return 0;
 53
 54	/* structure must be page aligned */
 55	if ((unsigned long)tiop & (PAGE_SIZE - 1))
 56		goto bad;
 57
 58	for (k = 0; k < tiop->num_resources; k++) {
 59		res = tiop->resource + k;
 60		len += roundup(resource_size(res), PAGE_SIZE);
 61		flags |= res->flags;
 62	}
 63
 64	/* support IORESOURCE_IO _or_ MEM, not both */
 65	if (hweight_long(flags) != 1)
 66		goto bad;
 67
 68	n = len >> PAGE_SHIFT;
 69
 70	if (n >= TRAPPED_PAGES_MAX)
 71		goto bad;
 72
 73	for (k = 0; k < n; k++)
 74		pages[k] = virt_to_page(tiop);
 75
 76	tiop->virt_base = vmap(pages, n, VM_MAP, PAGE_NONE);
 77	if (!tiop->virt_base)
 78		goto bad;
 79
 80	len = 0;
 81	for (k = 0; k < tiop->num_resources; k++) {
 82		res = tiop->resource + k;
 83		pr_info("trapped io 0x%08lx overrides %s 0x%08lx\n",
 84		       (unsigned long)(tiop->virt_base + len),
 85		       res->flags & IORESOURCE_IO ? "io" : "mmio",
 86		       (unsigned long)res->start);
 87		len += roundup(resource_size(res), PAGE_SIZE);
 88	}
 89
 90	tiop->magic = IO_TRAPPED_MAGIC;
 91	INIT_LIST_HEAD(&tiop->list);
 92	spin_lock_irq(&trapped_lock);
 93#ifdef CONFIG_HAS_IOPORT_MAP
 94	if (flags & IORESOURCE_IO)
 95		list_add(&tiop->list, &trapped_io);
 96#endif
 97#ifdef CONFIG_HAS_IOMEM
 98	if (flags & IORESOURCE_MEM)
 99		list_add(&tiop->list, &trapped_mem);
100#endif
101	spin_unlock_irq(&trapped_lock);
102
103	return 0;
104 bad:
105	pr_warning("unable to install trapped io filter\n");
106	return -1;
107}
108EXPORT_SYMBOL_GPL(register_trapped_io);
109
110void __iomem *match_trapped_io_handler(struct list_head *list,
111				       unsigned long offset,
112				       unsigned long size)
113{
114	unsigned long voffs;
115	struct trapped_io *tiop;
116	struct resource *res;
117	int k, len;
118	unsigned long flags;
119
120	spin_lock_irqsave(&trapped_lock, flags);
121	list_for_each_entry(tiop, list, list) {
122		voffs = 0;
123		for (k = 0; k < tiop->num_resources; k++) {
124			res = tiop->resource + k;
125			if (res->start == offset) {
126				spin_unlock_irqrestore(&trapped_lock, flags);
127				return tiop->virt_base + voffs;
128			}
129
130			len = resource_size(res);
131			voffs += roundup(len, PAGE_SIZE);
132		}
133	}
134	spin_unlock_irqrestore(&trapped_lock, flags);
135	return NULL;
136}
137EXPORT_SYMBOL_GPL(match_trapped_io_handler);
138
139static struct trapped_io *lookup_tiop(unsigned long address)
140{
141	pgd_t *pgd_k;
142	pud_t *pud_k;
143	pmd_t *pmd_k;
144	pte_t *pte_k;
145	pte_t entry;
146
147	pgd_k = swapper_pg_dir + pgd_index(address);
148	if (!pgd_present(*pgd_k))
149		return NULL;
150
151	pud_k = pud_offset(pgd_k, address);
152	if (!pud_present(*pud_k))
153		return NULL;
154
155	pmd_k = pmd_offset(pud_k, address);
156	if (!pmd_present(*pmd_k))
157		return NULL;
158
159	pte_k = pte_offset_kernel(pmd_k, address);
160	entry = *pte_k;
161
162	return pfn_to_kaddr(pte_pfn(entry));
163}
164
165static unsigned long lookup_address(struct trapped_io *tiop,
166				    unsigned long address)
167{
168	struct resource *res;
169	unsigned long vaddr = (unsigned long)tiop->virt_base;
170	unsigned long len;
171	int k;
172
173	for (k = 0; k < tiop->num_resources; k++) {
174		res = tiop->resource + k;
175		len = roundup(resource_size(res), PAGE_SIZE);
176		if (address < (vaddr + len))
177			return res->start + (address - vaddr);
178		vaddr += len;
179	}
180	return 0;
181}
182
183static unsigned long long copy_word(unsigned long src_addr, int src_len,
184				    unsigned long dst_addr, int dst_len)
185{
186	unsigned long long tmp = 0;
187
188	switch (src_len) {
189	case 1:
190		tmp = __raw_readb(src_addr);
191		break;
192	case 2:
193		tmp = __raw_readw(src_addr);
194		break;
195	case 4:
196		tmp = __raw_readl(src_addr);
197		break;
198	case 8:
199		tmp = __raw_readq(src_addr);
200		break;
201	}
202
203	switch (dst_len) {
204	case 1:
205		__raw_writeb(tmp, dst_addr);
206		break;
207	case 2:
208		__raw_writew(tmp, dst_addr);
209		break;
210	case 4:
211		__raw_writel(tmp, dst_addr);
212		break;
213	case 8:
214		__raw_writeq(tmp, dst_addr);
215		break;
216	}
217
218	return tmp;
219}
220
221static unsigned long from_device(void *dst, const void *src, unsigned long cnt)
222{
223	struct trapped_io *tiop;
224	unsigned long src_addr = (unsigned long)src;
225	unsigned long long tmp;
226
227	pr_debug("trapped io read 0x%08lx (%ld)\n", src_addr, cnt);
228	tiop = lookup_tiop(src_addr);
229	WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
230
231	src_addr = lookup_address(tiop, src_addr);
232	if (!src_addr)
233		return cnt;
234
235	tmp = copy_word(src_addr,
236			max_t(unsigned long, cnt,
237			      (tiop->minimum_bus_width / 8)),
238			(unsigned long)dst, cnt);
239
240	pr_debug("trapped io read 0x%08lx -> 0x%08llx\n", src_addr, tmp);
241	return 0;
242}
243
244static unsigned long to_device(void *dst, const void *src, unsigned long cnt)
245{
246	struct trapped_io *tiop;
247	unsigned long dst_addr = (unsigned long)dst;
248	unsigned long long tmp;
249
250	pr_debug("trapped io write 0x%08lx (%ld)\n", dst_addr, cnt);
251	tiop = lookup_tiop(dst_addr);
252	WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
253
254	dst_addr = lookup_address(tiop, dst_addr);
255	if (!dst_addr)
256		return cnt;
257
258	tmp = copy_word((unsigned long)src, cnt,
259			dst_addr, max_t(unsigned long, cnt,
260					(tiop->minimum_bus_width / 8)));
261
262	pr_debug("trapped io write 0x%08lx -> 0x%08llx\n", dst_addr, tmp);
263	return 0;
264}
265
266static struct mem_access trapped_io_access = {
267	from_device,
268	to_device,
269};
270
271int handle_trapped_io(struct pt_regs *regs, unsigned long address)
272{
273	mm_segment_t oldfs;
274	insn_size_t instruction;
275	int tmp;
276
277	if (trapped_io_disable)
278		return 0;
279	if (!lookup_tiop(address))
280		return 0;
281
282	WARN_ON(user_mode(regs));
283
284	oldfs = get_fs();
285	set_fs(KERNEL_DS);
286	if (copy_from_user(&instruction, (void *)(regs->pc),
287			   sizeof(instruction))) {
288		set_fs(oldfs);
289		return 0;
290	}
291
292	tmp = handle_unaligned_access(instruction, regs,
293				      &trapped_io_access, 1, address);
294	set_fs(oldfs);
295	return tmp == 0;
296}

  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 <linux/init.h>
 18#include <asm/mmu_context.h>
 19#include <linux/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_MAP
 26LIST_HEAD(trapped_io);
 27EXPORT_SYMBOL_GPL(trapped_io);
 28#endif
 29#ifdef CONFIG_HAS_IOMEM
 30LIST_HEAD(trapped_mem);
 31EXPORT_SYMBOL_GPL(trapped_mem);
 32#endif
 33static DEFINE_SPINLOCK(trapped_lock);
 34
 35static int trapped_io_disable __read_mostly;
 36
 37static int __init trapped_io_setup(char *__unused)
 38{
 39	trapped_io_disable = 1;
 40	return 1;
 41}
 42__setup("noiotrap", trapped_io_setup);
 43
 44int register_trapped_io(struct trapped_io *tiop)
 45{
 46	struct resource *res;
 47	unsigned long len = 0, flags = 0;
 48	struct page *pages[TRAPPED_PAGES_MAX];
 49	int k, n;
 50
 51	if (unlikely(trapped_io_disable))
 52		return 0;
 53
 54	/* structure must be page aligned */
 55	if ((unsigned long)tiop & (PAGE_SIZE - 1))
 56		goto bad;
 57
 58	for (k = 0; k < tiop->num_resources; k++) {
 59		res = tiop->resource + k;
 60		len += roundup(resource_size(res), PAGE_SIZE);
 61		flags |= res->flags;
 62	}
 63
 64	/* support IORESOURCE_IO _or_ MEM, not both */
 65	if (hweight_long(flags) != 1)
 66		goto bad;
 67
 68	n = len >> PAGE_SHIFT;
 69
 70	if (n >= TRAPPED_PAGES_MAX)
 71		goto bad;
 72
 73	for (k = 0; k < n; k++)
 74		pages[k] = virt_to_page(tiop);
 75
 76	tiop->virt_base = vmap(pages, n, VM_MAP, PAGE_NONE);
 77	if (!tiop->virt_base)
 78		goto bad;
 79
 80	len = 0;
 81	for (k = 0; k < tiop->num_resources; k++) {
 82		res = tiop->resource + k;
 83		pr_info("trapped io 0x%08lx overrides %s 0x%08lx\n",
 84		       (unsigned long)(tiop->virt_base + len),
 85		       res->flags & IORESOURCE_IO ? "io" : "mmio",
 86		       (unsigned long)res->start);
 87		len += roundup(resource_size(res), PAGE_SIZE);
 88	}
 89
 90	tiop->magic = IO_TRAPPED_MAGIC;
 91	INIT_LIST_HEAD(&tiop->list);
 92	spin_lock_irq(&trapped_lock);
 93#ifdef CONFIG_HAS_IOPORT_MAP
 94	if (flags & IORESOURCE_IO)
 95		list_add(&tiop->list, &trapped_io);
 96#endif
 97#ifdef CONFIG_HAS_IOMEM
 98	if (flags & IORESOURCE_MEM)
 99		list_add(&tiop->list, &trapped_mem);
100#endif
101	spin_unlock_irq(&trapped_lock);
102
103	return 0;
104 bad:
105	pr_warning("unable to install trapped io filter\n");
106	return -1;
107}
108EXPORT_SYMBOL_GPL(register_trapped_io);
109
110void __iomem *match_trapped_io_handler(struct list_head *list,
111				       unsigned long offset,
112				       unsigned long size)
113{
114	unsigned long voffs;
115	struct trapped_io *tiop;
116	struct resource *res;
117	int k, len;
118	unsigned long flags;
119
120	spin_lock_irqsave(&trapped_lock, flags);
121	list_for_each_entry(tiop, list, list) {
122		voffs = 0;
123		for (k = 0; k < tiop->num_resources; k++) {
124			res = tiop->resource + k;
125			if (res->start == offset) {
126				spin_unlock_irqrestore(&trapped_lock, flags);
127				return tiop->virt_base + voffs;
128			}
129
130			len = resource_size(res);
131			voffs += roundup(len, PAGE_SIZE);
132		}
133	}
134	spin_unlock_irqrestore(&trapped_lock, flags);
135	return NULL;
136}
137EXPORT_SYMBOL_GPL(match_trapped_io_handler);
138
139static struct trapped_io *lookup_tiop(unsigned long address)
140{
141	pgd_t *pgd_k;
142	pud_t *pud_k;
143	pmd_t *pmd_k;
144	pte_t *pte_k;
145	pte_t entry;
146
147	pgd_k = swapper_pg_dir + pgd_index(address);
148	if (!pgd_present(*pgd_k))
149		return NULL;
150
151	pud_k = pud_offset(pgd_k, address);
152	if (!pud_present(*pud_k))
153		return NULL;
154
155	pmd_k = pmd_offset(pud_k, address);
156	if (!pmd_present(*pmd_k))
157		return NULL;
158
159	pte_k = pte_offset_kernel(pmd_k, address);
160	entry = *pte_k;
161
162	return pfn_to_kaddr(pte_pfn(entry));
163}
164
165static unsigned long lookup_address(struct trapped_io *tiop,
166				    unsigned long address)
167{
168	struct resource *res;
169	unsigned long vaddr = (unsigned long)tiop->virt_base;
170	unsigned long len;
171	int k;
172
173	for (k = 0; k < tiop->num_resources; k++) {
174		res = tiop->resource + k;
175		len = roundup(resource_size(res), PAGE_SIZE);
176		if (address < (vaddr + len))
177			return res->start + (address - vaddr);
178		vaddr += len;
179	}
180	return 0;
181}
182
183static unsigned long long copy_word(unsigned long src_addr, int src_len,
184				    unsigned long dst_addr, int dst_len)
185{
186	unsigned long long tmp = 0;
187
188	switch (src_len) {
189	case 1:
190		tmp = __raw_readb(src_addr);
191		break;
192	case 2:
193		tmp = __raw_readw(src_addr);
194		break;
195	case 4:
196		tmp = __raw_readl(src_addr);
197		break;
198	case 8:
199		tmp = __raw_readq(src_addr);
200		break;
201	}
202
203	switch (dst_len) {
204	case 1:
205		__raw_writeb(tmp, dst_addr);
206		break;
207	case 2:
208		__raw_writew(tmp, dst_addr);
209		break;
210	case 4:
211		__raw_writel(tmp, dst_addr);
212		break;
213	case 8:
214		__raw_writeq(tmp, dst_addr);
215		break;
216	}
217
218	return tmp;
219}
220
221static unsigned long from_device(void *dst, const void *src, unsigned long cnt)
222{
223	struct trapped_io *tiop;
224	unsigned long src_addr = (unsigned long)src;
225	unsigned long long tmp;
226
227	pr_debug("trapped io read 0x%08lx (%ld)\n", src_addr, cnt);
228	tiop = lookup_tiop(src_addr);
229	WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
230
231	src_addr = lookup_address(tiop, src_addr);
232	if (!src_addr)
233		return cnt;
234
235	tmp = copy_word(src_addr,
236			max_t(unsigned long, cnt,
237			      (tiop->minimum_bus_width / 8)),
238			(unsigned long)dst, cnt);
239
240	pr_debug("trapped io read 0x%08lx -> 0x%08llx\n", src_addr, tmp);
241	return 0;
242}
243
244static unsigned long to_device(void *dst, const void *src, unsigned long cnt)
245{
246	struct trapped_io *tiop;
247	unsigned long dst_addr = (unsigned long)dst;
248	unsigned long long tmp;
249
250	pr_debug("trapped io write 0x%08lx (%ld)\n", dst_addr, cnt);
251	tiop = lookup_tiop(dst_addr);
252	WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
253
254	dst_addr = lookup_address(tiop, dst_addr);
255	if (!dst_addr)
256		return cnt;
257
258	tmp = copy_word((unsigned long)src, cnt,
259			dst_addr, max_t(unsigned long, cnt,
260					(tiop->minimum_bus_width / 8)));
261
262	pr_debug("trapped io write 0x%08lx -> 0x%08llx\n", dst_addr, tmp);
263	return 0;
264}
265
266static struct mem_access trapped_io_access = {
267	from_device,
268	to_device,
269};
270
271int handle_trapped_io(struct pt_regs *regs, unsigned long address)
272{
273	mm_segment_t oldfs;
274	insn_size_t instruction;
275	int tmp;
276
277	if (trapped_io_disable)
278		return 0;
279	if (!lookup_tiop(address))
280		return 0;
281
282	WARN_ON(user_mode(regs));
283
284	oldfs = get_fs();
285	set_fs(KERNEL_DS);
286	if (copy_from_user(&instruction, (void *)(regs->pc),
287			   sizeof(instruction))) {
288		set_fs(oldfs);
289		return 0;
290	}
291
292	tmp = handle_unaligned_access(instruction, regs,
293				      &trapped_io_access, 1, address);
294	set_fs(oldfs);
295	return tmp == 0;
296}