pciehp: fix NULL dereference in interrupt handler

[pandora-kernel.git] / drivers / pci / hotplug / pciehp_hpc.c

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 891f81a..425a0f6 100644 (file)
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -722,6 +722,7 @@ static irqreturn_t pcie_isr(int irq, void *dev_id)
 {
        struct controller *ctrl = (struct controller *)dev_id;
        u16 detected, intr_loc;
+       struct slot *p_slot;
 
        /*
         * In order to guarantee that all interrupt events are
@@ -756,21 +757,38 @@ static irqreturn_t pcie_isr(int irq, void *dev_id)
                wake_up_interruptible(&ctrl->queue);
        }
 
+       if (!(intr_loc & ~CMD_COMPLETED))
+               return IRQ_HANDLED;
+
+       /*
+        * Return without handling events if this handler routine is
+        * called before controller initialization is done. This may
+        * happen if hotplug event or another interrupt that shares
+        * the IRQ with pciehp arrives before slot initialization is
+        * done after interrupt handler is registered.
+        *
+        * FIXME - Need more structural fixes. We need to be ready to
+        * handle the event before installing interrupt handler.
+        */
+       p_slot = pciehp_find_slot(ctrl, ctrl->slot_device_offset);
+       if (!p_slot || !p_slot->hpc_ops)
+               return IRQ_HANDLED;
+
        /* Check MRL Sensor Changed */
        if (intr_loc & MRL_SENS_CHANGED)
-               pciehp_handle_switch_change(0, ctrl);
+               pciehp_handle_switch_change(p_slot);
 
        /* Check Attention Button Pressed */
        if (intr_loc & ATTN_BUTTN_PRESSED)
-               pciehp_handle_attention_button(0, ctrl);
+               pciehp_handle_attention_button(p_slot);
 
        /* Check Presence Detect Changed */
        if (intr_loc & PRSN_DETECT_CHANGED)
-               pciehp_handle_presence_change(0, ctrl);
+               pciehp_handle_presence_change(p_slot);
 
        /* Check Power Fault Detected */
        if (intr_loc & PWR_FAULT_DETECTED)
-               pciehp_handle_power_fault(0, ctrl);
+               pciehp_handle_power_fault(p_slot);
 
        return IRQ_HANDLED;
 }
@@ -1028,6 +1046,12 @@ static int pciehp_acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev)
 static int pcie_init_hardware_part1(struct controller *ctrl,
                                    struct pcie_device *dev)
 {
+       /* Clear all remaining event bits in Slot Status register */
+       if (pciehp_writew(ctrl, SLOTSTATUS, 0x1f)) {
+               err("%s: Cannot write to SLOTSTATUS register\n", __func__);
+               return -1;
+       }
+
        /* Mask Hot-plug Interrupt Enable */
        if (pcie_write_cmd(ctrl, 0, HP_INTR_ENABLE | CMD_CMPL_INTR_ENABLE)) {
                err("%s: Cannot mask hotplug interrupt enable\n", __func__);
@@ -1040,16 +1064,6 @@ int pcie_init_hardware_part2(struct controller *ctrl, struct pcie_device *dev)
 {
        u16 cmd, mask;
 
-       /*
-        * We need to clear all events before enabling hotplug interrupt
-        * notification mechanism in order for hotplug controler to
-        * generate interrupts.
-        */
-       if (pciehp_writew(ctrl, SLOTSTATUS, 0x1f)) {
-               err("%s: Cannot write to SLOTSTATUS register\n", __FUNCTION__);
-               return -1;
-       }
-
        cmd = PRSN_DETECT_ENABLE;
        if (ATTN_BUTTN(ctrl))
                cmd |= ATTN_BUTTN_ENABLE;