efi/libstub: fix efi_parse_options() ignoring the default command line

efi_convert_cmdline() always returns a size of at least 1 because it
counts the NUL terminator, so the "cmdline_size == 0" condition is never
satisfied.

Change it to check if the string starts with a NUL character to get the
intended behavior: to use CONFIG_CMDLINE when load_options_size == 0.

Fixes: 60f38de7a8d4 ("efi/libstub: Unify command line param parsing")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
index 958a680..2a1b43f 100644 (file)
--- a/drivers/firmware/efi/libstub/efi-stub.c
+++ b/drivers/firmware/efi/libstub/efi-stub.c
@@ -129,7 +129,7 @@ efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr)
 
        if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
            IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
-           cmdline_size == 0) {
+           cmdline[0] == 0) {
                status = efi_parse_options(CONFIG_CMDLINE);
                if (status != EFI_SUCCESS) {
                        efi_err("Failed to parse options\n");