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[IA64] prevent MCA when performing MMIO mmap to PCI config space

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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>
This commit is contained in:
Alex Chiang
2007-07-11 11:02:15 -06:00
committed by Tony Luck
parent 9e121327b3
commit 012b7105cc
3 changed files with 48 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
Documentation/ia64/aliasing-test.c
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@@ -19,6 +19,7 @@
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/pci.h>
int sum;
@@ -34,13 +35,19 @@ int map_mem(char *path, off_t offset, size_t length, int touch)
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 *) (offset + length))
while (c < (int *) (addr + length))
sum += *c++;
}
@@ -54,7 +61,7 @@ int map_mem(char *path, off_t offset, size_t length, int touch)
return 0;
}
int scan_sysfs(char *path, char *file, off_t offset, size_t length, int touch)
int scan_tree(char *path, char *file, off_t offset, size_t length, int touch)
{
struct dirent **namelist;
char *name, *path2;
@@ -93,7 +100,7 @@ int scan_sysfs(char *path, char *file, off_t offset, size_t length, int touch)
} else {
r = lstat(path2, &buf);
if (r == 0 && S_ISDIR(buf.st_mode)) {
rc = scan_sysfs(path2, file, offset, length, touch);
rc = scan_tree(path2, file, offset, length, touch);
if (rc < 0)
return rc;
}
@@ -238,10 +245,15 @@ int main()
else
fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");
scan_sysfs("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);
scan_sysfs("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);
scan_sysfs("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);
scan_sysfs("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);
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);
}