kernel-ark/Documentation/ia64/aliasing-test.c
Alex Chiang 012b7105cc [IA64] prevent MCA when performing MMIO mmap to PCI config space
Example memory map (HP rx7640 with 'default' acpiconfig setting, VGA disabled):
   0x00000000 - 0x3FFFBFFF  supports only WB (cacheable) access

If a user attempts to perform an MMIO mmap (using the PCIIOC_MMAP_IS_MEM ioctl)
to PCI config space (like mmap'ing and accessing memory at 0xA0000),
we will MCA because the kernel will attempt to use a mapping with the UC
attribute.

So check the memory attribute in kern_mmap and the EFI memmap. If WC is
requested, and WC or UC access is supported for the region, allow it.
Otherwise, use the same attribute the kernel uses.

Updates documentation and test cases as well.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2007-07-11 11:34:49 -07:00

260 lines
5.9 KiB
C

/*
* Exercise /dev/mem mmap cases that have been troublesome in the past
*
* (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
* Bjorn Helgaas <bjorn.helgaas@hp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/pci.h>
int sum;
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;
}
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, 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 rc;
}
char buf[1024];
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) {
perror("write");
return -1;
}
do {
rc = read(fd, buf, sizeof(buf));
if (rc > 0)
size += rc;
} while (rc > 0);
close(fd);
return size;
}
int scan_rom(char *path, char *file)
{
struct dirent **namelist;
char *name, *path2;
int i, n, r, rc, 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 ocurred. The
* important thing is that no MCA happened.
*/
if (rc > 0)
fprintf(stderr, "PASS: %s read %ld 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 rc;
}
int main()
{
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);
}