Make GPE disable more robust

Implemented another change for the GPE disable. We now perform a
read-change-write of the enable register instead of simply writing out the
cached enable mask. This will prevent inadvertent enabling of GPEs if a rogue
GPE is received during initialization (before GPE handlers are installed.)

http://bugzilla.kernel.org/show_bug.cgi?id=6217

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

2 files changed, 63 insertions, 5 deletions

diff --git a/drivers/acpi/events/evgpe.c b/drivers/acpi/events/evgpe.c
index 5354be44f876..e0339d4139a4 100644
--- a/drivers/acpi/events/evgpe.c
+++ b/drivers/acpi/events/evgpe.c
@@ -256,7 +256,7 @@ acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
                 return_ACPI_STATUS(status);
         }
 
-        /* Mark wake-disabled or HW disable, or both */
+        /* Clear the appropriate enabled flags for this GPE */
 
         switch (gpe_event_info->flags & ACPI_GPE_TYPE_MASK) {
         case ACPI_GPE_TYPE_WAKE:
@@ -273,13 +273,23 @@ acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
                 /* Disable the requested runtime GPE */
 
                 ACPI_CLEAR_BIT(gpe_event_info->flags, ACPI_GPE_RUN_ENABLED);
-
-                /* fallthrough */
+                break;
 
         default:
-                acpi_hw_write_gpe_enable_reg(gpe_event_info);
+                break;
         }
 
+        /*
+         * Even if we don't know the GPE type, make sure that we always
+         * disable it. low_disable_gpe will just clear the enable bit for this
+         * GPE and write it. It will not write out the current GPE enable mask,
+         * since this may inadvertently enable GPEs too early, if a rogue GPE has
+         * come in during ACPICA initialization - possibly as a result of AML or
+         * other code that has enabled the GPE.
+         */
+        status = acpi_hw_low_disable_gpe(gpe_event_info);
+        return_ACPI_STATUS(status);
+
         return_ACPI_STATUS(AE_OK);
 }
 
diff --git a/drivers/acpi/hardware/hwgpe.c b/drivers/acpi/hardware/hwgpe.c
index 14bc4f456ae8..58347d6c43f8 100644
--- a/drivers/acpi/hardware/hwgpe.c
+++ b/drivers/acpi/hardware/hwgpe.c
@@ -55,6 +55,54 @@ acpi_hw_enable_wakeup_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 
 /******************************************************************************
  *
+ * FUNCTION:    acpi_hw_low_disable_gpe
+ *
+ * PARAMETERS:  gpe_event_info      - Info block for the GPE to be disabled
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Disable a single GPE in the enable register.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+{
+        struct acpi_gpe_register_info *gpe_register_info;
+        acpi_status status;
+        u32 enable_mask;
+
+        /* Get the info block for the entire GPE register */
+
+        gpe_register_info = gpe_event_info->register_info;
+        if (!gpe_register_info) {
+                return (AE_NOT_EXIST);
+        }
+
+        /* Get current value of the enable register that contains this GPE */
+
+        status = acpi_hw_low_level_read(ACPI_GPE_REGISTER_WIDTH, &enable_mask,
+                                        &gpe_register_info->enable_address);
+        if (ACPI_FAILURE(status)) {
+                return (status);
+        }
+
+        /* Clear just the bit that corresponds to this GPE */
+
+        ACPI_CLEAR_BIT(enable_mask,
+                       ((u32) 1 <<
+                        (gpe_event_info->gpe_number -
+                         gpe_register_info->base_gpe_number)));
+
+        /* Write the updated enable mask */
+
+        status = acpi_hw_low_level_write(ACPI_GPE_REGISTER_WIDTH, enable_mask,
+                                         &gpe_register_info->enable_address);
+
+        return (status);
+}
+
+/******************************************************************************
+ *
  * FUNCTION:    acpi_hw_write_gpe_enable_reg
  *
  * PARAMETERS:  gpe_event_info      - Info block for the GPE to be enabled
@@ -68,7 +116,7 @@ acpi_hw_enable_wakeup_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
  ******************************************************************************/
 
 acpi_status
-acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info *gpe_event_info)
+acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info * gpe_event_info)
 {
         struct acpi_gpe_register_info *gpe_register_info;
         acpi_status status;