261 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Exercise /dev/mem mmap cases that have been troublesome in the past4 *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 22int sum;23 24static 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 62static 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(path2, path);85 strcat(path2, "/");86 strcat(path2, name);87 88 if (fnmatch(file, name, 0) == 0) {89 rc = map_mem(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(path2, file, offset, length, touch);102 if (rc < 0)103 return rc;104 }105 }106 107 result |= rc;108 free(path2);109 110skip:111 free(namelist[i]);112 }113 free(namelist);114 return result;115}116 117char buf[1024];118 119static 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 147static 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(path2, path);170 strcat(path2, "/");171 strcat(path2, name);172 173 if (fnmatch(file, name, 0) == 0) {174 rc = read_rom(path2);175 176 /*177 * It's OK if the ROM is unreadable. Maybe there178 * is no ROM, or some other error occurred. The179 * 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(path2, file);191 if (rc < 0)192 return rc;193 }194 }195 196 result |= rc;197 free(path2);198 199skip:200 free(namelist[i]);201 }202 free(namelist);203 return result;204}205 206int main(void)207{208 int rc;209 210 if (map_mem("/dev/mem", 0, 0xA0000, 1) == 0)211 fprintf(stderr, "PASS: /dev/mem 0x0-0xa0000 is readable\n");212 else213 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 know217 * how to poke the card the right way, it should respond, but it's218 * not safe in general. Many machines, e.g., Intel chipsets, cover219 * up a non-responding card by just returning -1, but others will220 * report the failure as a machine check.221 */222 if (map_mem("/dev/mem", 0xA0000, 0x20000, 0) == 0)223 fprintf(stderr, "PASS: /dev/mem 0xa0000-0xc0000 is mappable\n");224 else225 fprintf(stderr, "FAIL: /dev/mem 0xa0000-0xc0000 not accessible\n");226 227 if (map_mem("/dev/mem", 0xC0000, 0x40000, 1) == 0)228 fprintf(stderr, "PASS: /dev/mem 0xc0000-0x100000 is readable\n");229 else230 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 whole235 * thing at once. This is because the individual pieces use different236 * attributes, and there's no single attribute supported over the237 * whole region.238 */239 rc = map_mem("/dev/mem", 0, 1024*1024, 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 else245 fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");246 247 scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);248 scan_tree("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);249 scan_tree("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);250 scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);251 252 scan_rom("/sys/devices", "rom");253 254 scan_tree("/proc/bus/pci", "??.?", 0, 0xA0000, 1);255 scan_tree("/proc/bus/pci", "??.?", 0xA0000, 0x20000, 0);256 scan_tree("/proc/bus/pci", "??.?", 0xC0000, 0x40000, 1);257 scan_tree("/proc/bus/pci", "??.?", 0, 1024*1024, 0);258 259 return rc;260}261