1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Exercise /dev/mem mmap cases that have been troublesome in the past
4  *
5  * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
6  *	Bjorn Helgaas <bjorn.helgaas@hp.com>
7  */
8 
9 #include <stdlib.h>
10 #include <stdio.h>
11 #include <sys/types.h>
12 #include <dirent.h>
13 #include <fcntl.h>
14 #include <fnmatch.h>
15 #include <string.h>
16 #include <sys/ioctl.h>
17 #include <sys/mman.h>
18 #include <sys/stat.h>
19 #include <unistd.h>
20 #include <linux/pci.h>
21 
22 int sum;
23 
map_mem(char * path,off_t offset,size_t length,int touch)24 static int map_mem(char *path, off_t offset, size_t length, int touch)
25 {
26 	int fd, rc;
27 	void *addr;
28 	int *c;
29 
30 	fd = open(path, O_RDWR);
31 	if (fd == -1) {
32 		perror(path);
33 		return -1;
34 	}
35 
36 	if (fnmatch("/proc/bus/pci/*", path, 0) == 0) {
37 		rc = ioctl(fd, PCIIOC_MMAP_IS_MEM);
38 		if (rc == -1)
39 			perror("PCIIOC_MMAP_IS_MEM ioctl");
40 	}
41 
42 	addr = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, offset);
43 	if (addr == MAP_FAILED)
44 		return 1;
45 
46 	if (touch) {
47 		c = (int *) addr;
48 		while (c < (int *) (addr + length))
49 			sum += *c++;
50 	}
51 
52 	rc = munmap(addr, length);
53 	if (rc == -1) {
54 		perror("munmap");
55 		return -1;
56 	}
57 
58 	close(fd);
59 	return 0;
60 }
61 
scan_tree(char * path,char * file,off_t offset,size_t length,int touch)62 static int scan_tree(char *path, char *file, off_t offset, size_t length, int touch)
63 {
64 	struct dirent **namelist;
65 	char *name, *path2;
66 	int i, n, r, rc = 0, result = 0;
67 	struct stat buf;
68 
69 	n = scandir(path, &namelist, 0, alphasort);
70 	if (n < 0) {
71 		perror("scandir");
72 		return -1;
73 	}
74 
75 	for (i = 0; i < n; i++) {
76 		name = namelist[i]->d_name;
77 
78 		if (fnmatch(".", name, 0) == 0)
79 			goto skip;
80 		if (fnmatch("..", name, 0) == 0)
81 			goto skip;
82 
83 		path2 = malloc(strlen(path) + strlen(name) + 3);
84 		strcpy(path2, path);
85 		strcat(path2, "/");
86 		strcat(path2, name);
87 
88 		if (fnmatch(file, name, 0) == 0) {
89 			rc = map_mem(path2, offset, length, touch);
90 			if (rc == 0)
91 				fprintf(stderr, "PASS: %s 0x%lx-0x%lx is %s\n", path2, offset, offset + length, touch ? "readable" : "mappable");
92 			else if (rc > 0)
93 				fprintf(stderr, "PASS: %s 0x%lx-0x%lx not mappable\n", path2, offset, offset + length);
94 			else {
95 				fprintf(stderr, "FAIL: %s 0x%lx-0x%lx not accessible\n", path2, offset, offset + length);
96 				return rc;
97 			}
98 		} else {
99 			r = lstat(path2, &buf);
100 			if (r == 0 && S_ISDIR(buf.st_mode)) {
101 				rc = scan_tree(path2, file, offset, length, touch);
102 				if (rc < 0)
103 					return rc;
104 			}
105 		}
106 
107 		result |= rc;
108 		free(path2);
109 
110 skip:
111 		free(namelist[i]);
112 	}
113 	free(namelist);
114 	return result;
115 }
116 
117 char buf[1024];
118 
read_rom(char * path)119 static int read_rom(char *path)
120 {
121 	int fd, rc;
122 	size_t size = 0;
123 
124 	fd = open(path, O_RDWR);
125 	if (fd == -1) {
126 		perror(path);
127 		return -1;
128 	}
129 
130 	rc = write(fd, "1", 2);
131 	if (rc <= 0) {
132 		close(fd);
133 		perror("write");
134 		return -1;
135 	}
136 
137 	do {
138 		rc = read(fd, buf, sizeof(buf));
139 		if (rc > 0)
140 			size += rc;
141 	} while (rc > 0);
142 
143 	close(fd);
144 	return size;
145 }
146 
scan_rom(char * path,char * file)147 static int scan_rom(char *path, char *file)
148 {
149 	struct dirent **namelist;
150 	char *name, *path2;
151 	int i, n, r, rc = 0, result = 0;
152 	struct stat buf;
153 
154 	n = scandir(path, &namelist, 0, alphasort);
155 	if (n < 0) {
156 		perror("scandir");
157 		return -1;
158 	}
159 
160 	for (i = 0; i < n; i++) {
161 		name = namelist[i]->d_name;
162 
163 		if (fnmatch(".", name, 0) == 0)
164 			goto skip;
165 		if (fnmatch("..", name, 0) == 0)
166 			goto skip;
167 
168 		path2 = malloc(strlen(path) + strlen(name) + 3);
169 		strcpy(path2, path);
170 		strcat(path2, "/");
171 		strcat(path2, name);
172 
173 		if (fnmatch(file, name, 0) == 0) {
174 			rc = read_rom(path2);
175 
176 			/*
177 			 * It's OK if the ROM is unreadable.  Maybe there
178 			 * is no ROM, or some other error occurred.  The
179 			 * important thing is that no MCA happened.
180 			 */
181 			if (rc > 0)
182 				fprintf(stderr, "PASS: %s read %d bytes\n", path2, rc);
183 			else {
184 				fprintf(stderr, "PASS: %s not readable\n", path2);
185 				return rc;
186 			}
187 		} else {
188 			r = lstat(path2, &buf);
189 			if (r == 0 && S_ISDIR(buf.st_mode)) {
190 				rc = scan_rom(path2, file);
191 				if (rc < 0)
192 					return rc;
193 			}
194 		}
195 
196 		result |= rc;
197 		free(path2);
198 
199 skip:
200 		free(namelist[i]);
201 	}
202 	free(namelist);
203 	return result;
204 }
205 
main(void)206 int main(void)
207 {
208 	int rc;
209 
210 	if (map_mem("/dev/mem", 0, 0xA0000, 1) == 0)
211 		fprintf(stderr, "PASS: /dev/mem 0x0-0xa0000 is readable\n");
212 	else
213 		fprintf(stderr, "FAIL: /dev/mem 0x0-0xa0000 not accessible\n");
214 
215 	/*
216 	 * It's not safe to blindly read the VGA frame buffer.  If you know
217 	 * how to poke the card the right way, it should respond, but it's
218 	 * not safe in general.  Many machines, e.g., Intel chipsets, cover
219 	 * up a non-responding card by just returning -1, but others will
220 	 * report the failure as a machine check.
221 	 */
222 	if (map_mem("/dev/mem", 0xA0000, 0x20000, 0) == 0)
223 		fprintf(stderr, "PASS: /dev/mem 0xa0000-0xc0000 is mappable\n");
224 	else
225 		fprintf(stderr, "FAIL: /dev/mem 0xa0000-0xc0000 not accessible\n");
226 
227 	if (map_mem("/dev/mem", 0xC0000, 0x40000, 1) == 0)
228 		fprintf(stderr, "PASS: /dev/mem 0xc0000-0x100000 is readable\n");
229 	else
230 		fprintf(stderr, "FAIL: /dev/mem 0xc0000-0x100000 not accessible\n");
231 
232 	/*
233 	 * Often you can map all the individual pieces above (0-0xA0000,
234 	 * 0xA0000-0xC0000, and 0xC0000-0x100000), but can't map the whole
235 	 * thing at once.  This is because the individual pieces use different
236 	 * attributes, and there's no single attribute supported over the
237 	 * whole region.
238 	 */
239 	rc = map_mem("/dev/mem", 0, 1024*1024, 0);
240 	if (rc == 0)
241 		fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 is mappable\n");
242 	else if (rc > 0)
243 		fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 not mappable\n");
244 	else
245 		fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");
246 
247 	scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);
248 	scan_tree("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);
249 	scan_tree("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);
250 	scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);
251 
252 	scan_rom("/sys/devices", "rom");
253 
254 	scan_tree("/proc/bus/pci", "??.?", 0, 0xA0000, 1);
255 	scan_tree("/proc/bus/pci", "??.?", 0xA0000, 0x20000, 0);
256 	scan_tree("/proc/bus/pci", "??.?", 0xC0000, 0x40000, 1);
257 	scan_tree("/proc/bus/pci", "??.?", 0, 1024*1024, 0);
258 
259 	return rc;
260 }
261