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 (at) 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 } 264
