x86: zimage: Allow dumping the image from outside the module

At present it is possible to dump an image within the zimage command, but
it is also useful to be able to dump it from elsewhere, for example in a
loader that has special handling for the different zimage stages.

Export this feature as a new function.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/include/asm/zimage.h b/arch/x86/include/asm/zimage.h
index 64c0e6e..6679767 100644
--- a/arch/x86/include/asm/zimage.h
+++ b/arch/x86/include/asm/zimage.h
@@ -62,6 +62,16 @@
 int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
 		 ulong initrd_addr, ulong initrd_size, ulong cmdline_force);
 
+/**
+ * zimage_dump() - Dump the metadata of a zimage
+ *
+ * This shows all available information in a zimage that has been loaded.
+ *
+ * @base_ptr: Pointer to the boot parameters, typically at address
+ *	DEFAULT_SETUP_BASE
+ */
+void zimage_dump(struct boot_params *base_ptr);
+
 void setup_video(struct screen_info *screen_info);
 void setup_efi_info(struct efi_info *efi_info);