efi: Deduplicate efi_open_volume()

There's one ARM, one x86_32 and one x86_64 version of efi_open_volume()
which can be folded into a single shared version by masking their
differences with the efi_call_proto() macro introduced by commit:

  3552fdf29f01 ("efi: Allow bitness-agnostic protocol calls").

To be able to dereference the device_handle attribute from the
efi_loaded_image_t table in an arch- and bitness-agnostic manner,
introduce the efi_table_attr() macro (which already exists for x86)
to arm and arm64.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180720014726.24031-7-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 29 insertions, 2 deletions

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 50a9cab5a834..e94975f4655b 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -413,6 +413,34 @@ static efi_status_t efi_file_close(void *handle)
 	return efi_call_proto(efi_file_handle, close, handle);
 }
 
+static efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
+				    efi_loaded_image_t *image,
+				    efi_file_handle_t **__fh)
+{
+	efi_file_io_interface_t *io;
+	efi_file_handle_t *fh;
+	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
+	efi_status_t status;
+	void *handle = (void *)(unsigned long)efi_table_attr(efi_loaded_image,
+							     device_handle,
+							     image);
+
+	status = efi_call_early(handle_protocol, handle,
+				&fs_proto, (void **)&io);
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
+		return status;
+	}
+
+	status = efi_call_proto(efi_file_io_interface, open_volume, io, &fh);
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table_arg, "Failed to open volume\n");
+	else
+		*__fh = fh;
+
+	return status;
+}
+
 /*
  * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
  * option, e.g. efi=nochunk.
@@ -563,8 +591,7 @@ efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 
 		/* Only open the volume once. */
 		if (!i) {
-			status = efi_open_volume(sys_table_arg, image,
-						 (void **)&fh);
+			status = efi_open_volume(sys_table_arg, image, &fh);
 			if (status != EFI_SUCCESS)
 				goto free_files;
 		}