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authorDominik Brodowski <linux@dominikbrodowski.net>2010-03-29 21:40:35 +0200
committerDominik Brodowski <linux@dominikbrodowski.net>2010-05-10 10:23:19 +0200
commitcf26e8dc419424786575990aa133e76f5fb38657 (patch)
treef6913c925d7d3c050cd9c01516d017fd0b5ed277 /drivers/pcmcia
parentb19a7275dec4b470ea9abaae6129d21a0d75ab2f (diff)
downloadlinux-2.6.34-ux500-cf26e8dc419424786575990aa133e76f5fb38657.tar.gz
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>
Diffstat (limited to 'drivers/pcmcia')
-rw-r--r--drivers/pcmcia/rsrc_nonstatic.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/drivers/pcmcia/rsrc_nonstatic.c b/drivers/pcmcia/rsrc_nonstatic.c
index ba5256debde..dcd1a4ad3d6 100644
--- a/drivers/pcmcia/rsrc_nonstatic.c
+++ b/drivers/pcmcia/rsrc_nonstatic.c
@@ -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);