linux/Documentation/ia64/aliasing-test.c
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   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
  25int sum;
  26
  27static 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
  65static 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
 113skip:
 114                free(namelist[i]);
 115        }
 116        free(namelist);
 117        return result;
 118}
 119
 120char buf[1024];
 121
 122static 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
 149static 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 occurred.  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
 201skip:
 202                free(namelist[i]);
 203        }
 204        free(namelist);
 205        return result;
 206}
 207
 208int 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}
 263
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