efi_loader: reimplement LocateDevicePath
The current implementation of efi_locate_device_path does not match
the UEFI specification. It completely ignores the protocol
parameters.
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 9b5512f..565addf 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1080,36 +1080,6 @@
buffer_size, buffer));
}
-/*
- * Get the device path and handle of an device implementing a protocol.
- *
- * This function implements the LocateDevicePath service.
- * See the Unified Extensible Firmware Interface (UEFI) specification
- * for details.
- *
- * @protocol GUID of the protocol
- * @device_path device path
- * @device handle of the device
- * @return status code
- */
-static efi_status_t EFIAPI efi_locate_device_path(
- const efi_guid_t *protocol,
- struct efi_device_path **device_path,
- efi_handle_t *device)
-{
- struct efi_object *efiobj;
-
- EFI_ENTRY("%pUl, %p, %p", protocol, device_path, device);
-
- efiobj = efi_dp_find_obj(*device_path, device_path);
- if (!efiobj)
- return EFI_EXIT(EFI_NOT_FOUND);
-
- *device = efiobj->handle;
-
- return EFI_EXIT(EFI_SUCCESS);
-}
-
/* Collapses configuration table entries, removing index i */
static void efi_remove_configuration_table(int i)
{
@@ -1814,6 +1784,82 @@
}
/*
+ * Get the device path and handle of an device implementing a protocol.
+ *
+ * This function implements the LocateDevicePath service.
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @protocol GUID of the protocol
+ * @device_path device path
+ * @device handle of the device
+ * @return status code
+ */
+static efi_status_t EFIAPI efi_locate_device_path(
+ const efi_guid_t *protocol,
+ struct efi_device_path **device_path,
+ efi_handle_t *device)
+{
+ struct efi_device_path *dp;
+ size_t i;
+ struct efi_handler *handler;
+ efi_handle_t *handles;
+ size_t len, len_dp;
+ size_t len_best = 0;
+ efi_uintn_t no_handles;
+ u8 *remainder;
+ efi_status_t ret;
+
+ EFI_ENTRY("%pUl, %p, %p", protocol, device_path, device);
+
+ if (!protocol || !device_path || !*device_path || !device) {
+ ret = EFI_INVALID_PARAMETER;
+ goto out;
+ }
+
+ /* Find end of device path */
+ len = efi_dp_size(*device_path);
+
+ /* Get all handles implementing the protocol */
+ ret = EFI_CALL(efi_locate_handle_buffer(BY_PROTOCOL, protocol, NULL,
+ &no_handles, &handles));
+ if (ret != EFI_SUCCESS)
+ goto out;
+
+ for (i = 0; i < no_handles; ++i) {
+ /* Find the device path protocol */
+ ret = efi_search_protocol(handles[i], &efi_guid_device_path,
+ &handler);
+ if (ret != EFI_SUCCESS)
+ continue;
+ dp = (struct efi_device_path *)handler->protocol_interface;
+ len_dp = efi_dp_size(dp);
+ /*
+ * This handle can only be a better fit
+ * if its device path length is longer than the best fit and
+ * if its device path length is shorter of equal the searched
+ * device path.
+ */
+ if (len_dp <= len_best || len_dp > len)
+ continue;
+ /* Check if dp is a subpath of device_path */
+ if (memcmp(*device_path, dp, len_dp))
+ continue;
+ *device = handles[i];
+ len_best = len_dp;
+ }
+ if (len_best) {
+ remainder = (u8 *)*device_path + len_best;
+ *device_path = (struct efi_device_path *)remainder;
+ ret = EFI_SUCCESS;
+ } else {
+ ret = EFI_NOT_FOUND;
+ }
+out:
+ return EFI_EXIT(ret);
+}
+
+/*
* Install multiple protocol interfaces.
*
* This function implements the MultipleProtocolInterfaces service.