multiboot2: Add description of EFI image handle tags

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

doc/multiboot.texi

@@ -1295,6 +1295,34 @@ u32     | size = 8          |
 
 This tag indicates ExitBootServices wasn't called
 
+@subsection EFI 32-bit image handle pointer
+@example
+@group
+        +-------------------+
+u32     | type = 19         |
+u32     | size = 12         |
+u32     | pointer           |
+        +-------------------+
+@end group
+@end example
+
+This tag contains pointer to EFI i386 image handle.
+Usually it is boot loader image handle.
+
+@subsection EFI 64-bit image handle pointer
+@example
+@group
+        +-------------------+
+u32     | type = 20         |
+u32     | size = 16         |
+u64     | pointer           |
+        +-------------------+
+@end group
+@end example
+
+This tag contains pointer to EFI amd64 image handle.
+Usually it is boot loader image handle.
+
 @node Examples
 @chapter Examples
 

doc/multiboot2.h

@@ -60,6 +60,8 @@
 #define MULTIBOOT_TAG_TYPE_NETWORK           16
 #define MULTIBOOT_TAG_TYPE_EFI_MMAP          17
 #define MULTIBOOT_TAG_TYPE_EFI_BS            18
+#define MULTIBOOT_TAG_TYPE_EFI32_IH          19
+#define MULTIBOOT_TAG_TYPE_EFI64_IH          20
 
 #define MULTIBOOT_HEADER_TAG_END  0
 #define MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST  1
@@ -372,6 +374,20 @@ struct multiboot_tag_efi_mmap
   multiboot_uint8_t efi_mmap[0];
 }; 
 
+struct multiboot_tag_efi32_ih
+{
+  multiboot_uint32_t type;
+  multiboot_uint32_t size;
+  multiboot_uint32_t pointer;
+};
+
+struct multiboot_tag_efi64_ih
+{
+  multiboot_uint32_t type;
+  multiboot_uint32_t size;
+  multiboot_uint64_t pointer;
+};
+
 #endif /* ! ASM_FILE */
 
 #endif /* ! MULTIBOOT_HEADER */