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Based on kernel version 3.13. Page generated on 2014-01-20 22:03 EST.

1	/*
2	 * Exercise /dev/mem mmap cases that have been troublesome in the past
3	 *
4	 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
5	 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
6	 *
7	 * This program is free software; you can redistribute it and/or modify
8	 * it under the terms of the GNU General Public License version 2 as
9	 * published by the Free Software Foundation.
10	 */
11	
12	#include <stdlib.h>
13	#include <stdio.h>
14	#include <sys/types.h>
15	#include <dirent.h>
16	#include <fcntl.h>
17	#include <fnmatch.h>
18	#include <string.h>
19	#include <sys/ioctl.h>
20	#include <sys/mman.h>
21	#include <sys/stat.h>
22	#include <unistd.h>
23	#include <linux/pci.h>
24	
25	int sum;
26	
27	static int map_mem(char *path, off_t offset, size_t length, int touch)
28	{
29		int fd, rc;
30		void *addr;
31		int *c;
32	
33		fd = open(path, O_RDWR);
34		if (fd == -1) {
35			perror(path);
36			return -1;
37		}
38	
39		if (fnmatch("/proc/bus/pci/*", path, 0) == 0) {
40			rc = ioctl(fd, PCIIOC_MMAP_IS_MEM);
41			if (rc == -1)
42				perror("PCIIOC_MMAP_IS_MEM ioctl");
43		}
44	
45		addr = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, offset);
46		if (addr == MAP_FAILED)
47			return 1;
48	
49		if (touch) {
50			c = (int *) addr;
51			while (c < (int *) (addr + length))
52				sum += *c++;
53		}
54	
55		rc = munmap(addr, length);
56		if (rc == -1) {
57			perror("munmap");
58			return -1;
59		}
60	
61		close(fd);
62		return 0;
63	}
64	
65	static int scan_tree(char *path, char *file, off_t offset, size_t length, int touch)
66	{
67		struct dirent **namelist;
68		char *name, *path2;
69		int i, n, r, rc = 0, result = 0;
70		struct stat buf;
71	
72		n = scandir(path, &namelist, 0, alphasort);
73		if (n < 0) {
74			perror("scandir");
75			return -1;
76		}
77	
78		for (i = 0; i < n; i++) {
79			name = namelist[i]->d_name;
80	
81			if (fnmatch(".", name, 0) == 0)
82				goto skip;
83			if (fnmatch("..", name, 0) == 0)
84				goto skip;
85	
86			path2 = malloc(strlen(path) + strlen(name) + 3);
87			strcpy(path2, path);
88			strcat(path2, "/");
89			strcat(path2, name);
90	
91			if (fnmatch(file, name, 0) == 0) {
92				rc = map_mem(path2, offset, length, touch);
93				if (rc == 0)
94					fprintf(stderr, "PASS: %s 0x%lx-0x%lx is %s\n", path2, offset, offset + length, touch ? "readable" : "mappable");
95				else if (rc > 0)
96					fprintf(stderr, "PASS: %s 0x%lx-0x%lx not mappable\n", path2, offset, offset + length);
97				else {
98					fprintf(stderr, "FAIL: %s 0x%lx-0x%lx not accessible\n", path2, offset, offset + length);
99					return rc;
100				}
101			} else {
102				r = lstat(path2, &buf);
103				if (r == 0 && S_ISDIR(buf.st_mode)) {
104					rc = scan_tree(path2, file, offset, length, touch);
105					if (rc < 0)
106						return rc;
107				}
108			}
109	
110			result |= rc;
111			free(path2);
112	
113	skip:
114			free(namelist[i]);
115		}
116		free(namelist);
117		return result;
118	}
119	
120	char buf[1024];
121	
122	static int read_rom(char *path)
123	{
124		int fd, rc;
125		size_t size = 0;
126	
127		fd = open(path, O_RDWR);
128		if (fd == -1) {
129			perror(path);
130			return -1;
131		}
132	
133		rc = write(fd, "1", 2);
134		if (rc <= 0) {
135			close(fd);
136			perror("write");
137			return -1;
138		}
139	
140		do {
141			rc = read(fd, buf, sizeof(buf));
142			if (rc > 0)
143				size += rc;
144		} while (rc > 0);
145	
146		close(fd);
147		return size;
148	}
149	
150	static int scan_rom(char *path, char *file)
151	{
152		struct dirent **namelist;
153		char *name, *path2;
154		int i, n, r, rc = 0, result = 0;
155		struct stat buf;
156	
157		n = scandir(path, &namelist, 0, alphasort);
158		if (n < 0) {
159			perror("scandir");
160			return -1;
161		}
162	
163		for (i = 0; i < n; i++) {
164			name = namelist[i]->d_name;
165	
166			if (fnmatch(".", name, 0) == 0)
167				goto skip;
168			if (fnmatch("..", name, 0) == 0)
169				goto skip;
170	
171			path2 = malloc(strlen(path) + strlen(name) + 3);
172			strcpy(path2, path);
173			strcat(path2, "/");
174			strcat(path2, name);
175	
176			if (fnmatch(file, name, 0) == 0) {
177				rc = read_rom(path2);
178	
179				/*
180				 * It's OK if the ROM is unreadable.  Maybe there
181				 * is no ROM, or some other error occurred.  The
182				 * important thing is that no MCA happened.
183				 */
184				if (rc > 0)
185					fprintf(stderr, "PASS: %s read %d bytes\n", path2, rc);
186				else {
187					fprintf(stderr, "PASS: %s not readable\n", path2);
188					return rc;
189				}
190			} else {
191				r = lstat(path2, &buf);
192				if (r == 0 && S_ISDIR(buf.st_mode)) {
193					rc = scan_rom(path2, file);
194					if (rc < 0)
195						return rc;
196				}
197			}
198	
199			result |= rc;
200			free(path2);
201	
202	skip:
203			free(namelist[i]);
204		}
205		free(namelist);
206		return result;
207	}
208	
209	int main(void)
210	{
211		int rc;
212	
213		if (map_mem("/dev/mem", 0, 0xA0000, 1) == 0)
214			fprintf(stderr, "PASS: /dev/mem 0x0-0xa0000 is readable\n");
215		else
216			fprintf(stderr, "FAIL: /dev/mem 0x0-0xa0000 not accessible\n");
217	
218		/*
219		 * It's not safe to blindly read the VGA frame buffer.  If you know
220		 * how to poke the card the right way, it should respond, but it's
221		 * not safe in general.  Many machines, e.g., Intel chipsets, cover
222		 * up a non-responding card by just returning -1, but others will
223		 * report the failure as a machine check.
224		 */
225		if (map_mem("/dev/mem", 0xA0000, 0x20000, 0) == 0)
226			fprintf(stderr, "PASS: /dev/mem 0xa0000-0xc0000 is mappable\n");
227		else
228			fprintf(stderr, "FAIL: /dev/mem 0xa0000-0xc0000 not accessible\n");
229	
230		if (map_mem("/dev/mem", 0xC0000, 0x40000, 1) == 0)
231			fprintf(stderr, "PASS: /dev/mem 0xc0000-0x100000 is readable\n");
232		else
233			fprintf(stderr, "FAIL: /dev/mem 0xc0000-0x100000 not accessible\n");
234	
235		/*
236		 * Often you can map all the individual pieces above (0-0xA0000,
237		 * 0xA0000-0xC0000, and 0xC0000-0x100000), but can't map the whole
238		 * thing at once.  This is because the individual pieces use different
239		 * attributes, and there's no single attribute supported over the
240		 * whole region.
241		 */
242		rc = map_mem("/dev/mem", 0, 1024*1024, 0);
243		if (rc == 0)
244			fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 is mappable\n");
245		else if (rc > 0)
246			fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 not mappable\n");
247		else
248			fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");
249	
250		scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);
251		scan_tree("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);
252		scan_tree("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);
253		scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);
254	
255		scan_rom("/sys/devices", "rom");
256	
257		scan_tree("/proc/bus/pci", "??.?", 0, 0xA0000, 1);
258		scan_tree("/proc/bus/pci", "??.?", 0xA0000, 0x20000, 0);
259		scan_tree("/proc/bus/pci", "??.?", 0xC0000, 0x40000, 1);
260		scan_tree("/proc/bus/pci", "??.?", 0, 1024*1024, 0);
261	
262		return rc;
263	}
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