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/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                 perror("write");
 136                 return -1;
 137         }
 138
 139         do {
 140                 rc = read(fd, buf, sizeof(buf));
 141                 if (rc > 0)
 142                         size += rc;
 143         } while (rc > 0);
 144
 145         close(fd);
 146         return size;
 147 }
 148
 149 static int scan_rom(char *path, char *file)
 150 {
 151         struct dirent **namelist;
 152         char *name, *path2;
 153         int i, n, r, rc = 0, result = 0;
 154         struct stat buf;
 155
 156         n = scandir(path, &namelist, 0, alphasort);
 157         if (n < 0) {
 158                 perror("scandir");
 159                 return -1;
 160         }
 161
 162         for (i = 0; i < n; i++) {
 163                 name = namelist[i]->d_name;
 164
 165                 if (fnmatch(".", name, 0) == 0)
 166                         goto skip;
 167                 if (fnmatch("..", name, 0) == 0)
 168                         goto skip;
 169
 170                 path2 = malloc(strlen(path) + strlen(name) + 3);
 171                 strcpy(path2, path);
 172                 strcat(path2, "/");
 173                 strcat(path2, name);
 174
 175                 if (fnmatch(file, name, 0) == 0) {
 176                         rc = read_rom(path2);
 177
 178                         /*
 179                          * It's OK if the ROM is unreadable.  Maybe there
 180                          * is no ROM, or some other error ocurred.  The
 181                          * important thing is that no MCA happened.
 182                          */
 183                         if (rc > 0)
 184                                 fprintf(stderr, "PASS: %s read %d bytes\n", path2, rc);
 185                         else {
 186                                 fprintf(stderr, "PASS: %s not readable\n", path2);
 187                                 return rc;
 188                         }
 189                 } else {
 190                         r = lstat(path2, &buf);
 191                         if (r == 0 && S_ISDIR(buf.st_mode)) {
 192                                 rc = scan_rom(path2, file);
 193                                 if (rc < 0)
 194                                         return rc;
 195                         }
 196                 }
 197
 198                 result |= rc;
 199                 free(path2);
 200
 201 skip:
 202                 free(namelist[i]);
 203         }
 204         free(namelist);
 205         return result;
 206 }
 207
 208 int main(void)
 209 {
 210         int rc;
 211
 212         if (map_mem("/dev/mem", 0, 0xA0000, 1) == 0)
 213                 fprintf(stderr, "PASS: /dev/mem 0x0-0xa0000 is readable\n");
 214         else
 215                 fprintf(stderr, "FAIL: /dev/mem 0x0-0xa0000 not accessible\n");
 216
 217         /*
 218          * It's not safe to blindly read the VGA frame buffer.  If you know
 219          * how to poke the card the right way, it should respond, but it's
 220          * not safe in general.  Many machines, e.g., Intel chipsets, cover
 221          * up a non-responding card by just returning -1, but others will
 222          * report the failure as a machine check.
 223          */
 224         if (map_mem("/dev/mem", 0xA0000, 0x20000, 0) == 0)
 225                 fprintf(stderr, "PASS: /dev/mem 0xa0000-0xc0000 is mappable\n");
 226         else
 227                 fprintf(stderr, "FAIL: /dev/mem 0xa0000-0xc0000 not accessible\n");
 228
 229         if (map_mem("/dev/mem", 0xC0000, 0x40000, 1) == 0)
 230                 fprintf(stderr, "PASS: /dev/mem 0xc0000-0x100000 is readable\n");
 231         else
 232                 fprintf(stderr, "FAIL: /dev/mem 0xc0000-0x100000 not accessible\n");
 233
 234         /*
 235          * Often you can map all the individual pieces above (0-0xA0000,
 236          * 0xA0000-0xC0000, and 0xC0000-0x100000), but can't map the whole
 237          * thing at once.  This is because the individual pieces use different
 238          * attributes, and there's no single attribute supported over the
 239          * whole region.
 240          */
 241         rc = map_mem("/dev/mem", 0, 1024*1024, 0);
 242         if (rc == 0)
 243                 fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 is mappable\n");
 244         else if (rc > 0)
 245                 fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 not mappable\n");
 246         else
 247                 fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");
 248
 249         scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);
 250         scan_tree("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);
 251         scan_tree("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);
 252         scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);
 253
 254         scan_rom("/sys/devices", "rom");
 255
 256         scan_tree("/proc/bus/pci", "??.?", 0, 0xA0000, 1);
 257         scan_tree("/proc/bus/pci", "??.?", 0xA0000, 0x20000, 0);
 258         scan_tree("/proc/bus/pci", "??.?", 0xC0000, 0x40000, 1);
 259         scan_tree("/proc/bus/pci", "??.?", 0, 1024*1024, 0);
 260
 261         return rc;
 262 }