// SPDX-License-Identifier: GPL-2.0-only
/*
* Exercise /dev/mem mmap cases that have been troublesome in the past
*
* (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
* Bjorn Helgaas <[email protected]>
*/
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/pci.h>
int sum;
static int map_mem(char *path, off_t offset, size_t length, int touch)
{
int fd, rc;
void *addr;
int *c;
fd = open(path, O_RDWR);
if (fd == -1) {
perror(path);
return -1;
}
if (fnmatch("/proc/bus/pci/*", path, 0) == 0) {
rc = ioctl(fd, PCIIOC_MMAP_IS_MEM);
if (rc == -1)
perror("PCIIOC_MMAP_IS_MEM ioctl");
}
addr = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, offset);
if (addr == MAP_FAILED)
return 1;
if (touch) {
c = (int *) addr;
while (c < (int *) (addr + length))
sum += *c++;
}
rc = munmap(addr, length);
if (rc == -1) {
perror("munmap");
return -1;
}
close(fd);
return 0;
}
static int scan_tree(char *path, char *file, off_t offset, size_t length, int touch)
{
struct dirent **namelist;
char *name, *path2;
int i, n, r, rc = 0, result = 0;
struct stat buf;
n = scandir(path, &namelist, 0, alphasort);
if (n < 0) {
perror("scandir");
return -1;
}
for (i = 0; i < n; i++) {
name = namelist[i]->d_name;
if (fnmatch(".", name, 0) == 0)
goto skip;
if (fnmatch("..", name, 0) == 0)
goto skip;
path2 = malloc(strlen(path) + strlen(name) + 3);
strcpy(path2, path);
strcat(path2, "/");
strcat(path2, name);
if (fnmatch(file, name, 0) == 0) {
rc = map_mem(path2, offset, length, touch);
if (rc == 0)
fprintf(stderr, "PASS: %s 0x%lx-0x%lx is %s\n", path2, offset, offset + length, touch ? "readable" : "mappable");
else if (rc > 0)
fprintf(stderr, "PASS: %s 0x%lx-0x%lx not mappable\n", path2, offset, offset + length);
else {
fprintf(stderr, "FAIL: %s 0x%lx-0x%lx not accessible\n", path2, offset, offset + length);
return rc;
}
} else {
r = lstat(path2, &buf);
if (r == 0 && S_ISDIR(buf.st_mode)) {
rc = scan_tree(path2, file, offset, length, touch);
if (rc < 0)
return rc;
}
}
result |= rc;
free(path2);
skip:
free(namelist[i]);
}
free(namelist);
return result;
}
char buf[1024];
static int read_rom(char *path)
{
int fd, rc;
size_t size = 0;
fd = open(path, O_RDWR);
if (fd == -1) {
perror(path);
return -1;
}
rc = write(fd, "1", 2);
if (rc <= 0) {
close(fd);
perror("write");
return -1;
}
do {
rc = read(fd, buf, sizeof(buf));
if (rc > 0)
size += rc;
} while (rc > 0);
close(fd);
return size;
}
static int scan_rom(char *path, char *file)
{
struct dirent **namelist;
char *name, *path2;
int i, n, r, rc = 0, result = 0;
struct stat buf;
n = scandir(path, &namelist, 0, alphasort);
if (n < 0) {
perror("scandir");
return -1;
}
for (i = 0; i < n; i++) {
name = namelist[i]->d_name;
if (fnmatch(".", name, 0) == 0)
goto skip;
if (fnmatch("..", name, 0) == 0)
goto skip;
path2 = malloc(strlen(path) + strlen(name) + 3);
strcpy(path2, path);
strcat(path2, "/");
strcat(path2, name);
if (fnmatch(file, name, 0) == 0) {
rc = read_rom(path2);
/*
* It's OK if the ROM is unreadable. Maybe there
* is no ROM, or some other error occurred. The
* important thing is that no MCA happened.
*/
if (rc > 0)
fprintf(stderr, "PASS: %s read %d bytes\n", path2, rc);
else {
fprintf(stderr, "PASS: %s not readable\n", path2);
return rc;
}
} else {
r = lstat(path2, &buf);
if (r == 0 && S_ISDIR(buf.st_mode)) {
rc = scan_rom(path2, file);
if (rc < 0)
return rc;
}
}
result |= rc;
free(path2);
skip:
free(namelist[i]);
}
free(namelist);
return result;
}
int main(void)
{
int rc;
if (map_mem("/dev/mem", 0, 0xA0000, 1) == 0)
fprintf(stderr, "PASS: /dev/mem 0x0-0xa0000 is readable\n");
else
fprintf(stderr, "FAIL: /dev/mem 0x0-0xa0000 not accessible\n");
/*
* It's not safe to blindly read the VGA frame buffer. If you know
* how to poke the card the right way, it should respond, but it's
* not safe in general. Many machines, e.g., Intel chipsets, cover
* up a non-responding card by just returning -1, but others will
* report the failure as a machine check.
*/
if (map_mem("/dev/mem", 0xA0000, 0x20000, 0) == 0)
fprintf(stderr, "PASS: /dev/mem 0xa0000-0xc0000 is mappable\n");
else
fprintf(stderr, "FAIL: /dev/mem 0xa0000-0xc0000 not accessible\n");
if (map_mem("/dev/mem", 0xC0000, 0x40000, 1) == 0)
fprintf(stderr, "PASS: /dev/mem 0xc0000-0x100000 is readable\n");
else
fprintf(stderr, "FAIL: /dev/mem 0xc0000-0x100000 not accessible\n");
/*
* Often you can map all the individual pieces above (0-0xA0000,
* 0xA0000-0xC0000, and 0xC0000-0x100000), but can't map the whole
* thing at once. This is because the individual pieces use different
* attributes, and there's no single attribute supported over the
* whole region.
*/
rc = map_mem("/dev/mem", 0, 1024*1024, 0);
if (rc == 0)
fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 is mappable\n");
else if (rc > 0)
fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 not mappable\n");
else
fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");
scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);
scan_tree("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);
scan_tree("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);
scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);
scan_rom("/sys/devices", "rom");
scan_tree("/proc/bus/pci", "??.?", 0, 0xA0000, 1);
scan_tree("/proc/bus/pci", "??.?", 0xA0000, 0x20000, 0);
scan_tree("/proc/bus/pci", "??.?", 0xC0000, 0x40000, 1);
scan_tree("/proc/bus/pci", "??.?", 0, 1024*1024, 0);
return rc;
}
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