cmd: bootefi: restore ability to boot arbitrary blob

Up until commit 5f59518a ("efi_loader: setting boot device"), we
could boot an arbitrary blob with bootefi. Indeed, efi_run_image() even
has a special case for missing device paths indicating a payload that
was directly loaded via JTAG, for example.

Restore the ability to inject a UEFI payload into memory and `bootefi`
it. If the address passed isn't the last PE-COFF loaded, then we'll
wipe out the pre-existing DP/Image information and let efi_run_image()
synthesize a memory device path.

An image size is required if we're booting an arbitrary payload, and
the FDT argument has been changed to accept `-`. The size could be
deduced from the image header, but it's required anyways as an explicit
acknowledgment that one's trying to boot an arbitrary payload rather
than accidentally using the wrong address in the single-addr form.

Fixes: 5f59518a ("efi_loader: setting boot device")
Signed-off-by: NKyle Evans <kevans@FreeBSD.org>
Reviewed-by: NHeinrich Schuchardt <heinrich.schuchardt@canonical.com>

cmd/bootefi.c

@@ -422,10 +422,11 @@ static int do_efibootmgr(void)
  * Set up memory image for the binary to be loaded, prepare device path, and
  * then call do_bootefi_exec() to execute it.
  *
- * @image_opt:	string of image start address
+ * @image_opt:	string with image start address
+ * @size_opt:	string with image size or NULL
  * Return:	status code
  */
-static int do_bootefi_image(const char *image_opt)
+static int do_bootefi_image(const char *image_opt, const char *size_opt)
 {
 	void *image_buf;
 	unsigned long addr, size;
@@ -443,14 +444,21 @@ static int do_bootefi_image(const char *image_opt)
 		/* Check that a numeric value was passed */
 		if (!addr)
 			return CMD_RET_USAGE;
-
 		image_buf = map_sysmem(addr, 0);
 
-		if (image_buf != image_addr) {
-			log_err("No UEFI binary known at %s\n", image_opt);
-			return CMD_RET_FAILURE;
+		if (size_opt) {
+			size = strtoul(size_opt, NULL, 16);
+			if (!size)
+				return CMD_RET_USAGE;
+			efi_clear_bootdev();
+		} else {
+			if (image_buf != image_addr) {
+				log_err("No UEFI binary known at %s\n",
+					image_opt);
+				return CMD_RET_FAILURE;
+			}
+			size = image_size;
 		}
-		size = image_size;
 	}
 	ret = efi_run_image(image_buf, size);
 
@@ -654,7 +662,7 @@ static int do_bootefi(struct cmd_tbl *cmdtp, int flag, int argc,
 		return CMD_RET_FAILURE;
 	}
 
-	if (argc > 2) {
+	if (argc > 2 && strcmp(argv[2], "-")) {
 		uintptr_t fdt_addr;
 
 		fdt_addr = hextoul(argv[2], NULL);
@@ -677,15 +685,15 @@ static int do_bootefi(struct cmd_tbl *cmdtp, int flag, int argc,
 		return do_efi_selftest();
 #endif
 
-	return do_bootefi_image(argv[1]);
+	return do_bootefi_image(argv[1], argc > 3 ? argv[3] : NULL);
 }
 
 #ifdef CONFIG_SYS_LONGHELP
 static char bootefi_help_text[] =
-	"<image address> [fdt address]\n"
-	"  - boot EFI payload stored at address <image address>.\n"
-	"    If specified, the device tree located at <fdt address> gets\n"
-	"    exposed as EFI configuration table.\n"
+	"<image address> [fdt address [image size]]\n"
+	"  - boot EFI payload stored at <image address>\n"
+	"    fdt address, address of device-tree or '-'\n"
+	"    image size, required if image not preloaded\n"
 #ifdef CONFIG_CMD_BOOTEFI_HELLO
 	"bootefi hello\n"
 	"  - boot a sample Hello World application stored within U-Boot\n"
@@ -707,7 +715,7 @@ static char bootefi_help_text[] =
 #endif
 
 U_BOOT_CMD(
-	bootefi, 3, 0, do_bootefi,
+	bootefi, 4, 0, do_bootefi,
 	"Boots an EFI payload from memory",
 	bootefi_help_text
 );