efi/x86: Add a quirk to support command line arguments on Dell EFI firmware

At least some versions of Dell EFI firmware pass the entire
EFI_LOAD_OPTION descriptor, rather than just the OptionalData part, to
the loaded image. This was verified with firmware revision 2.15.0 on a
Dell Precision T3620 by Jacobo Pantoja.

To handle this, add a quirk to check if the options look like a valid
EFI_LOAD_OPTION descriptor, and if so, use the OptionalData part as the
command line.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reported-by: Jacobo Pantoja <jacobopantoja@gmail.com>
Link: https://lore.kernel.org/linux-efi/20200907170021.GA2284449@rani.riverdale.lan/
Link: https://lore.kernel.org/r/20200914213535.933454-2-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 9ea87a28d303..2d7abcd99de9 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -708,6 +708,35 @@ union efi_load_file_protocol {
 	} mixed_mode;
 };
 
+typedef struct {
+	u32 attributes;
+	u16 file_path_list_length;
+	u8 variable_data[];
+	// efi_char16_t description[];
+	// efi_device_path_protocol_t file_path_list[];
+	// u8 optional_data[];
+} __packed efi_load_option_t;
+
+#define EFI_LOAD_OPTION_ACTIVE		0x0001U
+#define EFI_LOAD_OPTION_FORCE_RECONNECT	0x0002U
+#define EFI_LOAD_OPTION_HIDDEN		0x0008U
+#define EFI_LOAD_OPTION_CATEGORY	0x1f00U
+#define   EFI_LOAD_OPTION_CATEGORY_BOOT	0x0000U
+#define   EFI_LOAD_OPTION_CATEGORY_APP	0x0100U
+
+#define EFI_LOAD_OPTION_BOOT_MASK \
+	(EFI_LOAD_OPTION_ACTIVE|EFI_LOAD_OPTION_HIDDEN|EFI_LOAD_OPTION_CATEGORY)
+#define EFI_LOAD_OPTION_MASK (EFI_LOAD_OPTION_FORCE_RECONNECT|EFI_LOAD_OPTION_BOOT_MASK)
+
+typedef struct {
+	u32 attributes;
+	u16 file_path_list_length;
+	const efi_char16_t *description;
+	const efi_device_path_protocol_t *file_path_list;
+	size_t optional_data_size;
+	const void *optional_data;
+} efi_load_option_unpacked_t;
+
 void efi_pci_disable_bridge_busmaster(void);
 
 typedef efi_status_t (*efi_exit_boot_map_processing)(
@@ -750,6 +779,8 @@ __printf(1, 2) int efi_printk(char const *fmt, ...);
 
 void efi_free(unsigned long size, unsigned long addr);
 
+void efi_apply_loadoptions_quirk(const void **load_options, int *load_options_size);
+
 char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len);
 
 efi_status_t efi_get_memory_map(struct efi_boot_memmap *map);