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 --- v3 remove trailing dot in comment v2 no change --- lib/efi_loader/efi_boottime.c | 106 ++++++++++++++++++++++++++++++------------ 1 file changed, 76 insertions(+), 30 deletions(-)
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c index 9b5512f086..565addfc3f 100644 --- a/lib/efi_loader/efi_boottime.c +++ b/lib/efi_loader/efi_boottime.c @@ -1080,36 +1080,6 @@ static efi_status_t EFIAPI efi_locate_handle_ext( 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) { @@ -1813,6 +1783,82 @@ static efi_status_t EFIAPI efi_locate_protocol(const efi_guid_t *protocol, return EFI_EXIT(EFI_NOT_FOUND); }
+/* + * 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. *