[efi] Raise TPL within EFI_DRIVER_BINDING_PROTOCOL entry points

Debugged-by: Rob Taglang <rob@privatemachines.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/interface/efi/efi_driver.c b/src/interface/efi/efi_driver.c
index de0f61f929e3daad33fa24c2638de19a18769077..fe73630fd2dde10b5468677bbf3bcca474ed9315 100644 (file)
--- a/src/interface/efi/efi_driver.c
+++ b/src/interface/efi/efi_driver.c
@@ -95,7 +95,9 @@ struct efi_device * efidev_parent ( struct device *dev ) {
 static EFI_STATUS EFIAPI
 efi_driver_supported ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                       EFI_HANDLE device, EFI_DEVICE_PATH_PROTOCOL *child ) {
+       EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct efi_driver *efidrv;
+       EFI_TPL saved_tpl;
        int rc;
 
        DBGCP ( device, "EFIDRV %s DRIVER_SUPPORTED",
@@ -111,17 +113,22 @@ efi_driver_supported ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                return EFI_ALREADY_STARTED;
        }
 
+       /* Raise TPL */
+       saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
+
        /* Look for a driver claiming to support this device */
        for_each_table_entry ( efidrv, EFI_DRIVERS ) {
                if ( ( rc = efidrv->supported ( device ) ) == 0 ) {
                        DBGC ( device, "EFIDRV %s has driver \"%s\"\n",
                               efi_handle_name ( device ), efidrv->name );
+                       bs->RestoreTPL ( saved_tpl );
                        return 0;
                }
        }
        DBGCP ( device, "EFIDRV %s has no driver\n",
                efi_handle_name ( device ) );
 
+       bs->RestoreTPL ( saved_tpl );
        return EFI_UNSUPPORTED;
 }
 
@@ -145,6 +152,7 @@ efi_driver_start ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
        } path;
        EFI_DEVICE_PATH_PROTOCOL *path_end;
        size_t path_len;
+       EFI_TPL saved_tpl;
        EFI_STATUS efirc;
        int rc;
 
@@ -162,6 +170,9 @@ efi_driver_start ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                goto err_already_started;
        }
 
+       /* Raise TPL */
+       saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
+
        /* Do nothing if we are currently disconnecting drivers */
        if ( efi_driver_disconnecting ) {
                DBGC ( device, "EFIDRV %s refusing to start during "
@@ -215,6 +226,7 @@ efi_driver_start ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                        DBGC ( device, "EFIDRV %s using driver \"%s\"\n",
                               efi_handle_name ( device ),
                               efidev->driver->name );
+                       bs->RestoreTPL ( saved_tpl );
                        return 0;
                }
                DBGC ( device, "EFIDRV %s could not start driver \"%s\": %s\n",
@@ -232,6 +244,7 @@ efi_driver_start ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
        }
  err_open_path:
  err_disconnecting:
+       bs->RestoreTPL ( saved_tpl );
  err_already_started:
        return efirc;
 }
@@ -250,8 +263,10 @@ static EFI_STATUS EFIAPI
 efi_driver_stop ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                  EFI_HANDLE device, UINTN num_children,
                  EFI_HANDLE *children ) {
+       EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct efi_driver *efidrv;
        struct efi_device *efidev;
+       EFI_TPL saved_tpl;
        UINTN i;
 
        DBGC ( device, "EFIDRV %s DRIVER_STOP", efi_handle_name ( device ) );
@@ -269,6 +284,9 @@ efi_driver_stop ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                return EFI_DEVICE_ERROR;
        }
 
+       /* Raise TPL */
+       saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
+
        /* Stop this device */
        efidrv = efidev->driver;
        assert ( efidrv != NULL );
@@ -276,6 +294,7 @@ efi_driver_stop ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
        list_del ( &efidev->dev.siblings );
        free ( efidev );
 
+       bs->RestoreTPL ( saved_tpl );
        return 0;
 }