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