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pcmcia: do not autoadd root PCI bus resources 

On the PCI root bus on the x86 architecture, the risk of hitting
some strange system devices is too high: If a driver isn't loaded,
the resources are not claimed; even if a driver is loaded, it
may not request all resources or even the wrong one. We can neither
trust the rest of the kernel nor ACPI/PNP and CRS parsing to get it
right.

Therefore, explicitly spell out what safeguards we provide, and add
a safeguard to only use resources which are set up exclusively for
the secondary PCI bus (non-subtractive mode): the risk of hitting
system devices is quite low, as they usually aren't connected to
the secondary PCI bus.

CC: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2010-03-29 21:40:35 +02:00
parent b19a7275de
commit cf26e8dc41
1 changed files with 29 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
drivers/pcmcia/rsrc_nonstatic.c
View File

@ -935,23 +935,42 @@ static int nonstatic_autoadd_resources(struct pcmcia_socket *s)
return -ENODEV;
#if defined(CONFIG_X86)
/* If this is the root bus, the risk of hitting
* some strange system devices which aren't protected
* by either ACPI resource tables or properly requested
* resources is too big. Therefore, don't do auto-adding
* of resources at the moment.
/* If this is the root bus, the risk of hitting some strange
* system devices is too high: If a driver isn't loaded, the
* resources are not claimed; even if a driver is loaded, it
* may not request all resources or even the wrong one. We
* can neither trust the rest of the kernel nor ACPI/PNP and
* CRS parsing to get it right. Therefore, use several
* safeguards:
*
* - Do not auto-add resources if the CardBus bridge is on
* the PCI root bus
*
* - Avoid any I/O ports < 0x100.
*
* - On PCI-PCI bridges, only use resources which are set up
* exclusively for the secondary PCI bus: the risk of hitting
* system devices is quite low, as they usually aren't
* connected to the secondary PCI bus.
*/
if (s->cb_dev->bus->number == 0)
return -EINVAL;
#endif
for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
res = s->cb_dev->bus->resource[i];
#else
pci_bus_for_each_resource(s->cb_dev->bus, res, i) {
#endif
if (!res)
continue;
if (res->flags & IORESOURCE_IO) {
/* safeguard against the root resource, where the
* risk of hitting any other device would be too
* high */
if (res == &ioport_resource)
continue;
dev_printk(KERN_INFO, &s->cb_dev->dev,
"pcmcia: parent PCI bridge window: %pR\n",
res);
@ -961,8 +980,12 @@ static int nonstatic_autoadd_resources(struct pcmcia_socket *s)
}
if (res->flags & IORESOURCE_MEM) {
/* safeguard against the root resource, where the
* risk of hitting any other device would be too
* high */
if (res == &iomem_resource)
continue;
dev_printk(KERN_INFO, &s->cb_dev->dev,
"pcmcia: parent PCI bridge window: %pR\n",
res);