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 | |
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 | |
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(p: path2, q: path); |
85 | strcat(p: path2, q: "/" ); |
86 | strcat(p: path2, q: name); |
87 | |
88 | if (fnmatch(file, name, 0) == 0) { |
89 | rc = map_mem(path: 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(path: 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 | |
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 | |
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(p: path2, q: path); |
170 | strcat(p: path2, q: "/" ); |
171 | strcat(p: path2, q: name); |
172 | |
173 | if (fnmatch(file, name, 0) == 0) { |
174 | rc = read_rom(path: 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(path: 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 | |
206 | int main(void) |
207 | { |
208 | int rc; |
209 | |
210 | if (map_mem(path: "/dev/mem" , offset: 0, length: 0xA0000, touch: 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(path: "/dev/mem" , offset: 0xA0000, length: 0x20000, touch: 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(path: "/dev/mem" , offset: 0xC0000, length: 0x40000, touch: 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(path: "/dev/mem" , offset: 0, length: 1024*1024, touch: 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(path: "/sys/class/pci_bus" , file: "legacy_mem" , offset: 0, length: 0xA0000, touch: 1); |
248 | scan_tree(path: "/sys/class/pci_bus" , file: "legacy_mem" , offset: 0xA0000, length: 0x20000, touch: 0); |
249 | scan_tree(path: "/sys/class/pci_bus" , file: "legacy_mem" , offset: 0xC0000, length: 0x40000, touch: 1); |
250 | scan_tree(path: "/sys/class/pci_bus" , file: "legacy_mem" , offset: 0, length: 1024*1024, touch: 0); |
251 | |
252 | scan_rom(path: "/sys/devices" , file: "rom" ); |
253 | |
254 | scan_tree(path: "/proc/bus/pci" , file: "??.?" , offset: 0, length: 0xA0000, touch: 1); |
255 | scan_tree(path: "/proc/bus/pci" , file: "??.?" , offset: 0xA0000, length: 0x20000, touch: 0); |
256 | scan_tree(path: "/proc/bus/pci" , file: "??.?" , offset: 0xC0000, length: 0x40000, touch: 1); |
257 | scan_tree(path: "/proc/bus/pci" , file: "??.?" , offset: 0, length: 1024*1024, touch: 0); |
258 | |
259 | return rc; |
260 | } |
261 | |