[WATCHDOG] iTCO_wdt: fix memory corruption when RCBA is disabled by hardware

According to 9.1.33 on p.343 of ICH8.pdf RCBA can be disabled by
hardware if bit 0 of RCBA register is not set.

Perform correct check for this to prevent memory corruption under
some virtual machines where this feature is disabled.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vasily Averin <vvs@openvz.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 6284961..6a51edd 100644 (file)
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -666,6 +666,11 @@ static int __devinit iTCO_wdt_init(struct pci_dev *pdev,
           GCS = RCBA + ICH6_GCS(0x3410). */
        if (iTCO_wdt_private.iTCO_version == 2) {
                pci_read_config_dword(pdev, 0xf0, &base_address);
+               if ((base_address & 1) == 0) {
+                       printk(KERN_ERR PFX "RCBA is disabled by harddware\n");
+                       ret = -ENODEV;
+                       goto out;
+               }
                RCBA = base_address & 0xffffc000;
                iTCO_wdt_private.gcs = ioremap((RCBA + 0x3410), 4);
        }
@@ -675,7 +680,7 @@ static int __devinit iTCO_wdt_init(struct pci_dev *pdev,
                printk(KERN_ERR PFX "failed to reset NO_REBOOT flag, "
                                        "reboot disabled by hardware\n");
                ret = -ENODEV;  /* Cannot reset NO_REBOOT bit */
-               goto out;
+               goto out_unmap;
        }
 
        /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
@@ -686,7 +691,7 @@ static int __devinit iTCO_wdt_init(struct pci_dev *pdev,
                printk(KERN_ERR PFX
                        "I/O address 0x%04lx already in use\n", SMI_EN);
                ret = -EIO;
-               goto out;
+               goto out_unmap;
        }
        /* Bit 13: TCO_EN -> 0 = Disables TCO logic generating an SMI# */
        val32 = inl(SMI_EN);
@@ -742,9 +747,10 @@ unreg_region:
        release_region(TCOBASE, 0x20);
 unreg_smi_en:
        release_region(SMI_EN, 4);
-out:
+out_unmap:
        if (iTCO_wdt_private.iTCO_version == 2)
                iounmap(iTCO_wdt_private.gcs);
+out:
        pci_dev_put(iTCO_wdt_private.pdev);
        iTCO_wdt_private.ACPIBASE = 0;
        return ret;