[PATCH v2 3/3] x86/boot: Introduce the kernel_info.setup_type_max

[Daniel Kiper <daniel.kiper@oracle.com>]

This field contains maximal allowed type for setup_data and
setup_indirect structs.

And finally bump setup_header version in arch/x86/boot/header.S.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Reviewed-by: Eric Snowberg <eric.snowberg@oracle.com>
---
 Documentation/x86/boot.rst             | 10 +++++++++-
 arch/x86/boot/compressed/kernel_info.S |  4 ++++
 arch/x86/boot/header.S                 |  2 +-
 arch/x86/include/uapi/asm/bootparam.h  |  3 +++
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst
index 23d3726d54fc..63609fd0517f 100644
--- a/Documentation/x86/boot.rst
+++ b/Documentation/x86/boot.rst
@@ -73,7 +73,8 @@ Protocol 2.14:	BURNT BY INCORRECT COMMIT ae7e1238e68f2a472a125673ab506d49158c188
 		(x86/boot: Add ACPI RSDP address to setup_header)
 		DO NOT USE!!! ASSUME SAME AS 2.13.
 
-Protocol 2.15:	(Kernel 5.3) Added the kernel_info and setup_indirect.
+Protocol 2.15:	(Kernel 5.3) Added the kernel_info, kernel_info.setup_type_max
+		and setup_indirect.
 =============	============================================================
 
 .. note::
@@ -980,6 +981,13 @@ Offset/size:	0x0004/4
   This field contains the size of the kernel_info including kernel_info.header.
   It should be used by the boot loader to detect supported fields in the kernel_info.
 
+============	==============
+Field name:	setup_type_max
+Offset/size:	0x0008/4
+============	==============
+
+  This field contains maximal allowed type for setup_data and setup_indirect structs.
+
 
 The Image Checksum
 ==================
diff --git a/arch/x86/boot/compressed/kernel_info.S b/arch/x86/boot/compressed/kernel_info.S
index 3f1cb301b9ff..2f28aabf6558 100644
--- a/arch/x86/boot/compressed/kernel_info.S
+++ b/arch/x86/boot/compressed/kernel_info.S
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 
+#include <asm/bootparam.h>
+
 	.section ".rodata.kernel_info", "a"
 
 	.global kernel_info
@@ -9,4 +11,6 @@ kernel_info:
 	.ascii	"InfO"
         /* Size. */
 	.long	kernel_info_end - kernel_info
+        /* Maximal allowed type for setup_data and setup_indirect structs. */
+	.long	SETUP_TYPE_MAX
 kernel_info_end:
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index ec6a25a43148..893a456663ab 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -300,7 +300,7 @@ _start:
 	# Part 2 of the header, from the old setup.S
 
 		.ascii	"HdrS"		# header signature
-		.word	0x020d		# header version number (>= 0x0105)
+		.word	0x020f		# header version number (>= 0x0105)
 					# or else old loadlin-1.5 will fail)
 		.globl realmode_swtch
 realmode_swtch:	.word	0, 0		# default_switch, SETUPSEG
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index aaaa17fa6ad6..2ba870dae6f3 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -12,6 +12,9 @@
 #define SETUP_JAILHOUSE			6
 #define SETUP_INDIRECT			7
 
+/* max(SETUP_*) */
+#define SETUP_TYPE_MAX			SETUP_INDIRECT
+
 /* ram_size flags */
 #define RAMDISK_IMAGE_START_MASK	0x07FF
 #define RAMDISK_PROMPT_FLAG		0x8000
-- 
2.11.0