[PATCH] ppc64: PCI device-node failure detection

OpenFirmware marks devices as failed in the device-tree when a hardware
problem is detected.  The kernel needs to fail config reads/writes to
prevent a kernel crash when incorrect data is read.

This patch validates that the device-node is not marked "fail" when
config space reads/writes are attempted.

Signed-off-by: Jake Moilanen <moilanen@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 17 insertions, 2 deletions

diff --git a/arch/ppc64/kernel/rtas_pci.c b/arch/ppc64/kernel/rtas_pci.c
index 1048817befb8..1dccadaddd1d 100644
--- a/arch/ppc64/kernel/rtas_pci.c
+++ b/arch/ppc64/kernel/rtas_pci.c
@@ -58,6 +58,21 @@ static int config_access_valid(struct device_node *dn, int where)
         return 0;
 }
 
+static int of_device_available(struct device_node * dn)
+{
+        char * status;
+
+        status = get_property(dn, "status", NULL);
+
+        if (!status)
+                return 1;
+
+        if (!strcmp(status, "okay"))
+                return 1;
+
+        return 0;
+}
+
 static int rtas_read_config(struct device_node *dn, int where, int size, u32 *val)
 {
         int returnval = -1;
@@ -103,7 +118,7 @@ static int rtas_pci_read_config(struct pci_bus *bus,
 
         /* Search only direct children of the bus */
         for (dn = busdn->child; dn; dn = dn->sibling)
-                if (dn->devfn == devfn)
+                if (dn->devfn == devfn && of_device_available(dn))
                         return rtas_read_config(dn, where, size, val);
         return PCIBIOS_DEVICE_NOT_FOUND;
 }
@@ -146,7 +161,7 @@ static int rtas_pci_write_config(struct pci_bus *bus,
 
         /* Search only direct children of the bus */
         for (dn = busdn->child; dn; dn = dn->sibling)
-                if (dn->devfn == devfn)
+                if (dn->devfn == devfn && of_device_available(dn))
                         return rtas_write_config(dn, where, size, val);
         return PCIBIOS_DEVICE_NOT_FOUND;
 }