Documentation/ia64/aliasing-test.c

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