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From:   Changbin Du <changbin.du@gmail.com>
To:     corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de
Cc:     x86@kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, Changbin Du <changbin.du@gmail.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Subject: [PATCH v4 02/27] Documentation: x86: convert boot.txt to reST
Date:   Wed,  8 May 2019 23:21:16 +0800
Message-Id: <20190508152141.8740-3-changbin.du@gmail.com>
In-Reply-To: <20190508152141.8740-1-changbin.du@gmail.com>
References: <20190508152141.8740-1-changbin.du@gmail.com>
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This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
 Documentation/x86/{boot.txt => boot.rst} | 528 ++++++++++++++---------
 Documentation/x86/index.rst              |   2 +
 2 files changed, 327 insertions(+), 203 deletions(-)
 rename Documentation/x86/{boot.txt => boot.rst} (73%)

diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.rst
similarity index 73%
rename from Documentation/x86/boot.txt
rename to Documentation/x86/boot.rst
index 223e484a1304..08a2f100c0e6 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.rst
@@ -1,5 +1,8 @@
-		     THE LINUX/x86 BOOT PROTOCOL
-		     ---------------------------
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================
+The Linux/x86 Boot Protocol
+===========================
 
 On the x86 platform, the Linux kernel uses a rather complicated boot
 convention.  This has evolved partially due to historical aspects, as
@@ -10,88 +13,91 @@ real-mode DOS as a mainstream operating system.
 
 Currently, the following versions of the Linux/x86 boot protocol exist.
 
-Old kernels:	zImage/Image support only.  Some very early kernels
+=============	============================================================
+Old kernels	zImage/Image support only.  Some very early kernels
 		may not even support a command line.
 
-Protocol 2.00:	(Kernel 1.3.73) Added bzImage and initrd support, as
+Protocol 2.00	(Kernel 1.3.73) Added bzImage and initrd support, as
 		well as a formalized way to communicate between the
 		boot loader and the kernel.  setup.S made relocatable,
 		although the traditional setup area still assumed
 		writable.
 
-Protocol 2.01:	(Kernel 1.3.76) Added a heap overrun warning.
+Protocol 2.01	(Kernel 1.3.76) Added a heap overrun warning.
 
-Protocol 2.02:	(Kernel 2.4.0-test3-pre3) New command line protocol.
+Protocol 2.02	(Kernel 2.4.0-test3-pre3) New command line protocol.
 		Lower the conventional memory ceiling.	No overwrite
 		of the traditional setup area, thus making booting
 		safe for systems which use the EBDA from SMM or 32-bit
 		BIOS entry points.  zImage deprecated but still
 		supported.
 
-Protocol 2.03:	(Kernel 2.4.18-pre1) Explicitly makes the highest possible
+Protocol 2.03	(Kernel 2.4.18-pre1) Explicitly makes the highest possible
 		initrd address available to the bootloader.
 
-Protocol 2.04:	(Kernel 2.6.14) Extend the syssize field to four bytes.
+Protocol 2.04	(Kernel 2.6.14) Extend the syssize field to four bytes.
 
-Protocol 2.05:	(Kernel 2.6.20) Make protected mode kernel relocatable.
+Protocol 2.05	(Kernel 2.6.20) Make protected mode kernel relocatable.
 		Introduce relocatable_kernel and kernel_alignment fields.
 
-Protocol 2.06:	(Kernel 2.6.22) Added a field that contains the size of
+Protocol 2.06	(Kernel 2.6.22) Added a field that contains the size of
 		the boot command line.
 
-Protocol 2.07:	(Kernel 2.6.24) Added paravirtualised boot protocol.
+Protocol 2.07	(Kernel 2.6.24) Added paravirtualised boot protocol.
 		Introduced hardware_subarch and hardware_subarch_data
 		and KEEP_SEGMENTS flag in load_flags.
 
-Protocol 2.08:	(Kernel 2.6.26) Added crc32 checksum and ELF format
+Protocol 2.08	(Kernel 2.6.26) Added crc32 checksum and ELF format
 		payload. Introduced payload_offset and payload_length
 		fields to aid in locating the payload.
 
-Protocol 2.09:	(Kernel 2.6.26) Added a field of 64-bit physical
+Protocol 2.09	(Kernel 2.6.26) Added a field of 64-bit physical
 		pointer to single linked list of struct	setup_data.
 
-Protocol 2.10:	(Kernel 2.6.31) Added a protocol for relaxed alignment
+Protocol 2.10	(Kernel 2.6.31) Added a protocol for relaxed alignment
 		beyond the kernel_alignment added, new init_size and
 		pref_address fields.  Added extended boot loader IDs.
 
-Protocol 2.11:	(Kernel 3.6) Added a field for offset of EFI handover
+Protocol 2.11	(Kernel 3.6) Added a field for offset of EFI handover
 		protocol entry point.
 
-Protocol 2.12:	(Kernel 3.8) Added the xloadflags field and extension fields
+Protocol 2.12	(Kernel 3.8) Added the xloadflags field and extension fields
 		to struct boot_params for loading bzImage and ramdisk
 		above 4G in 64bit.
 
-Protocol 2.13:	(Kernel 3.14) Support 32- and 64-bit flags being set in
+Protocol 2.13	(Kernel 3.14) Support 32- and 64-bit flags being set in
 		xloadflags to support booting a 64-bit kernel from 32-bit
 		EFI
+=============	============================================================
 
-**** MEMORY LAYOUT
 
-The traditional memory map for the kernel loader, used for Image or
-zImage kernels, typically looks like:
-
-	|			 |
-0A0000	+------------------------+
-	|  Reserved for BIOS	 |	Do not use.  Reserved for BIOS EBDA.
-09A000	+------------------------+
-	|  Command line		 |
-	|  Stack/heap		 |	For use by the kernel real-mode code.
-098000	+------------------------+	
-	|  Kernel setup		 |	The kernel real-mode code.
-090200	+------------------------+
-	|  Kernel boot sector	 |	The kernel legacy boot sector.
-090000	+------------------------+
-	|  Protected-mode kernel |	The bulk of the kernel image.
-010000	+------------------------+
-	|  Boot loader		 |	<- Boot sector entry point 0000:7C00
-001000	+------------------------+
-	|  Reserved for MBR/BIOS |
-000800	+------------------------+
-	|  Typically used by MBR |
-000600	+------------------------+ 
-	|  BIOS use only	 |
-000000	+------------------------+
+Memory Layout
+=============
 
+The traditional memory map for the kernel loader, used for Image or
+zImage kernels, typically looks like::
+
+		|			 |
+	0A0000	+------------------------+
+		|  Reserved for BIOS	 |	Do not use.  Reserved for BIOS EBDA.
+	09A000	+------------------------+
+		|  Command line		 |
+		|  Stack/heap		 |	For use by the kernel real-mode code.
+	098000	+------------------------+
+		|  Kernel setup		 |	The kernel real-mode code.
+	090200	+------------------------+
+		|  Kernel boot sector	 |	The kernel legacy boot sector.
+	090000	+------------------------+
+		|  Protected-mode kernel |	The bulk of the kernel image.
+	010000	+------------------------+
+		|  Boot loader		 |	<- Boot sector entry point 0000:7C00
+	001000	+------------------------+
+		|  Reserved for MBR/BIOS |
+	000800	+------------------------+
+		|  Typically used by MBR |
+	000600	+------------------------+
+		|  BIOS use only	 |
+	000000	+------------------------+
 
 When using bzImage, the protected-mode kernel was relocated to
 0x100000 ("high memory"), and the kernel real-mode block (boot sector,
@@ -116,36 +122,36 @@ zImage or old bzImage kernels, which need data written into the
 above the 0x9A000 point; too many BIOSes will break above that point.
 
 For a modern bzImage kernel with boot protocol version >= 2.02, a
-memory layout like the following is suggested:
-
-	~                        ~
-        |  Protected-mode kernel |
-100000  +------------------------+
-	|  I/O memory hole	 |
-0A0000	+------------------------+
-	|  Reserved for BIOS	 |	Leave as much as possible unused
-	~                        ~
-	|  Command line		 |	(Can also be below the X+10000 mark)
-X+10000	+------------------------+
-	|  Stack/heap		 |	For use by the kernel real-mode code.
-X+08000	+------------------------+	
-	|  Kernel setup		 |	The kernel real-mode code.
-	|  Kernel boot sector	 |	The kernel legacy boot sector.
-X       +------------------------+
-	|  Boot loader		 |	<- Boot sector entry point 0000:7C00
-001000	+------------------------+
-	|  Reserved for MBR/BIOS |
-000800	+------------------------+
-	|  Typically used by MBR |
-000600	+------------------------+ 
-	|  BIOS use only	 |
-000000	+------------------------+
-
-... where the address X is as low as the design of the boot loader
-permits.
-
-
-**** THE REAL-MODE KERNEL HEADER
+memory layout like the following is suggested::
+
+		~                        ~
+		|  Protected-mode kernel |
+	100000  +------------------------+
+		|  I/O memory hole	 |
+	0A0000	+------------------------+
+		|  Reserved for BIOS	 |	Leave as much as possible unused
+		~                        ~
+		|  Command line		 |	(Can also be below the X+10000 mark)
+	X+10000	+------------------------+
+		|  Stack/heap		 |	For use by the kernel real-mode code.
+	X+08000	+------------------------+
+		|  Kernel setup		 |	The kernel real-mode code.
+		|  Kernel boot sector	 |	The kernel legacy boot sector.
+	X       +------------------------+
+		|  Boot loader		 |	<- Boot sector entry point 0000:7C00
+	001000	+------------------------+
+		|  Reserved for MBR/BIOS |
+	000800	+------------------------+
+		|  Typically used by MBR |
+	000600	+------------------------+
+		|  BIOS use only	 |
+	000000	+------------------------+
+
+  ... where the address X is as low as the design of the boot loader permits.
+
+
+The Real-Mode Kernel Header
+===========================
 
 In the following text, and anywhere in the kernel boot sequence, "a
 sector" refers to 512 bytes.  It is independent of the actual sector
@@ -159,61 +165,63 @@ sectors (1K) and then examine the bootup sector size.
 
 The header looks like:
 
-Offset	Proto	Name		Meaning
-/Size
-
-01F1/1	ALL(1	setup_sects	The size of the setup in sectors
-01F2/2	ALL	root_flags	If set, the root is mounted readonly
-01F4/4	2.04+(2	syssize		The size of the 32-bit code in 16-byte paras
-01F8/2	ALL	ram_size	DO NOT USE - for bootsect.S use only
-01FA/2	ALL	vid_mode	Video mode control
-01FC/2	ALL	root_dev	Default root device number
-01FE/2	ALL	boot_flag	0xAA55 magic number
-0200/2	2.00+	jump		Jump instruction
-0202/4	2.00+	header		Magic signature "HdrS"
-0206/2	2.00+	version		Boot protocol version supported
-0208/4	2.00+	realmode_swtch	Boot loader hook (see below)
-020C/2	2.00+	start_sys_seg	The load-low segment (0x1000) (obsolete)
-020E/2	2.00+	kernel_version	Pointer to kernel version string
-0210/1	2.00+	type_of_loader	Boot loader identifier
-0211/1	2.00+	loadflags	Boot protocol option flags
-0212/2	2.00+	setup_move_size	Move to high memory size (used with hooks)
-0214/4	2.00+	code32_start	Boot loader hook (see below)
-0218/4	2.00+	ramdisk_image	initrd load address (set by boot loader)
-021C/4	2.00+	ramdisk_size	initrd size (set by boot loader)
-0220/4	2.00+	bootsect_kludge	DO NOT USE - for bootsect.S use only
-0224/2	2.01+	heap_end_ptr	Free memory after setup end
-0226/1	2.02+(3 ext_loader_ver	Extended boot loader version
-0227/1	2.02+(3	ext_loader_type	Extended boot loader ID
-0228/4	2.02+	cmd_line_ptr	32-bit pointer to the kernel command line
-022C/4	2.03+	initrd_addr_max	Highest legal initrd address
-0230/4	2.05+	kernel_alignment Physical addr alignment required for kernel
-0234/1	2.05+	relocatable_kernel Whether kernel is relocatable or not
-0235/1	2.10+	min_alignment	Minimum alignment, as a power of two
-0236/2	2.12+	xloadflags	Boot protocol option flags
-0238/4	2.06+	cmdline_size	Maximum size of the kernel command line
-023C/4	2.07+	hardware_subarch Hardware subarchitecture
-0240/8	2.07+	hardware_subarch_data Subarchitecture-specific data
-0248/4	2.08+	payload_offset	Offset of kernel payload
-024C/4	2.08+	payload_length	Length of kernel payload
-0250/8	2.09+	setup_data	64-bit physical pointer to linked list
-				of struct setup_data
-0258/8	2.10+	pref_address	Preferred loading address
-0260/4	2.10+	init_size	Linear memory required during initialization
-0264/4	2.11+	handover_offset	Offset of handover entry point
-
-(1) For backwards compatibility, if the setup_sects field contains 0, the
-    real value is 4.
-
-(2) For boot protocol prior to 2.04, the upper two bytes of the syssize
-    field are unusable, which means the size of a bzImage kernel
-    cannot be determined.
-
-(3) Ignored, but safe to set, for boot protocols 2.02-2.09.
+===========	========	=====================	============================================
+Offset/Size	Proto		Name			Meaning
+===========	========	=====================	============================================
+01F1/1		ALL(1)		setup_sects		The size of the setup in sectors
+01F2/2		ALL		root_flags		If set, the root is mounted readonly
+01F4/4		2.04+(2)	syssize			The size of the 32-bit code in 16-byte paras
+01F8/2		ALL		ram_size		DO NOT USE - for bootsect.S use only
+01FA/2		ALL		vid_mode		Video mode control
+01FC/2		ALL		root_dev		Default root device number
+01FE/2		ALL		boot_flag		0xAA55 magic number
+0200/2		2.00+		jump			Jump instruction
+0202/4		2.00+		header			Magic signature "HdrS"
+0206/2		2.00+		version			Boot protocol version supported
+0208/4		2.00+		realmode_swtch		Boot loader hook (see below)
+020C/2		2.00+		start_sys_seg		The load-low segment (0x1000) (obsolete)
+020E/2		2.00+		kernel_version		Pointer to kernel version string
+0210/1		2.00+		type_of_loader		Boot loader identifier
+0211/1		2.00+		loadflags		Boot protocol option flags
+0212/2		2.00+		setup_move_size		Move to high memory size (used with hooks)
+0214/4		2.00+		code32_start		Boot loader hook (see below)
+0218/4		2.00+		ramdisk_image		initrd load address (set by boot loader)
+021C/4		2.00+		ramdisk_size		initrd size (set by boot loader)
+0220/4		2.00+		bootsect_kludge		DO NOT USE - for bootsect.S use only
+0224/2		2.01+		heap_end_ptr		Free memory after setup end
+0226/1		2.02+(3)	ext_loader_ver		Extended boot loader version
+0227/1		2.02+(3)	ext_loader_type		Extended boot loader ID
+0228/4		2.02+		cmd_line_ptr		32-bit pointer to the kernel command line
+022C/4		2.03+		initrd_addr_max		Highest legal initrd address
+0230/4		2.05+		kernel_alignment	Physical addr alignment required for kernel
+0234/1		2.05+		relocatable_kernel	Whether kernel is relocatable or not
+0235/1		2.10+		min_alignment		Minimum alignment, as a power of two
+0236/2		2.12+		xloadflags		Boot protocol option flags
+0238/4		2.06+		cmdline_size		Maximum size of the kernel command line
+023C/4		2.07+		hardware_subarch	Hardware subarchitecture
+0240/8		2.07+		hardware_subarch_data	Subarchitecture-specific data
+0248/4		2.08+		payload_offset		Offset of kernel payload
+024C/4		2.08+		payload_length		Length of kernel payload
+0250/8		2.09+		setup_data		64-bit physical pointer to linked list
+							of struct setup_data
+0258/8		2.10+		pref_address		Preferred loading address
+0260/4		2.10+		init_size		Linear memory required during initialization
+0264/4		2.11+		handover_offset		Offset of handover entry point
+===========	========	=====================	============================================
+
+.. note::
+  (1) For backwards compatibility, if the setup_sects field contains 0, the
+      real value is 4.
+
+  (2) For boot protocol prior to 2.04, the upper two bytes of the syssize
+      field are unusable, which means the size of a bzImage kernel
+      cannot be determined.
+
+  (3) Ignored, but safe to set, for boot protocols 2.02-2.09.
 
 If the "HdrS" (0x53726448) magic number is not found at offset 0x202,
 the boot protocol version is "old".  Loading an old kernel, the
-following parameters should be assumed:
+following parameters should be assumed::
 
 	Image type = zImage
 	initrd not supported
@@ -225,7 +233,8 @@ setting fields in the header, you must make sure only to set fields
 supported by the protocol version in use.
 
 
-**** DETAILS OF HEADER FIELDS
+Details of Harder Fileds
+========================
 
 For each field, some are information from the kernel to the bootloader
 ("read"), some are expected to be filled out by the bootloader
@@ -239,106 +248,132 @@ boot loaders can ignore those fields.
 
 The byte order of all fields is littleendian (this is x86, after all.)
 
+============	===========
 Field name:	setup_sects
 Type:		read
 Offset/size:	0x1f1/1
 Protocol:	ALL
+============	===========
 
   The size of the setup code in 512-byte sectors.  If this field is
   0, the real value is 4.  The real-mode code consists of the boot
   sector (always one 512-byte sector) plus the setup code.
 
-Field name:	 root_flags
-Type:		 modify (optional)
-Offset/size:	 0x1f2/2
-Protocol:	 ALL
+============	=================
+Field name:	root_flags
+Type:		modify (optional)
+Offset/size:	0x1f2/2
+Protocol:	ALL
+============	=================
 
   If this field is nonzero, the root defaults to readonly.  The use of
   this field is deprecated; use the "ro" or "rw" options on the
   command line instead.
 
+============	===============================================
 Field name:	syssize
 Type:		read
 Offset/size:	0x1f4/4 (protocol 2.04+) 0x1f4/2 (protocol ALL)
 Protocol:	2.04+
+============	===============================================
 
   The size of the protected-mode code in units of 16-byte paragraphs.
   For protocol versions older than 2.04 this field is only two bytes
   wide, and therefore cannot be trusted for the size of a kernel if
   the LOAD_HIGH flag is set.
 
+============	===============
 Field name:	ram_size
 Type:		kernel internal
 Offset/size:	0x1f8/2
 Protocol:	ALL
+============	===============
 
   This field is obsolete.
 
+============	===================
 Field name:	vid_mode
 Type:		modify (obligatory)
 Offset/size:	0x1fa/2
+============	===================
 
   Please see the section on SPECIAL COMMAND LINE OPTIONS.
 
+============	=================
 Field name:	root_dev
 Type:		modify (optional)
 Offset/size:	0x1fc/2
 Protocol:	ALL
+============	=================
 
   The default root device device number.  The use of this field is
   deprecated, use the "root=" option on the command line instead.
 
+============	=========
 Field name:	boot_flag
 Type:		read
 Offset/size:	0x1fe/2
 Protocol:	ALL
+============	=========
 
   Contains 0xAA55.  This is the closest thing old Linux kernels have
   to a magic number.
 
+============	=======
 Field name:	jump
 Type:		read
 Offset/size:	0x200/2
 Protocol:	2.00+
+============	=======
 
   Contains an x86 jump instruction, 0xEB followed by a signed offset
   relative to byte 0x202.  This can be used to determine the size of
   the header.
 
+============	=======
 Field name:	header
 Type:		read
 Offset/size:	0x202/4
 Protocol:	2.00+
+============	=======
 
   Contains the magic number "HdrS" (0x53726448).
 
+============	=======
 Field name:	version
 Type:		read
 Offset/size:	0x206/2
 Protocol:	2.00+
+============	=======
 
   Contains the boot protocol version, in (major << 8)+minor format,
   e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version
   10.17.
 
+============	=================
 Field name:	realmode_swtch
 Type:		modify (optional)
 Offset/size:	0x208/4
 Protocol:	2.00+
+============	=================
 
   Boot loader hook (see ADVANCED BOOT LOADER HOOKS below.)
 
+============	=============
 Field name:	start_sys_seg
 Type:		read
 Offset/size:	0x20c/2
 Protocol:	2.00+
+============	=============
 
   The load low segment (0x1000).  Obsolete.
 
+============	==============
 Field name:	kernel_version
 Type:		read
 Offset/size:	0x20e/2
 Protocol:	2.00+
+============	==============
 
   If set to a nonzero value, contains a pointer to a NUL-terminated
   human-readable kernel version number string, less 0x200.  This can
@@ -348,17 +383,19 @@ Protocol:	2.00+
   For example, if this value is set to 0x1c00, the kernel version
   number string can be found at offset 0x1e00 in the kernel file.
   This is a valid value if and only if the "setup_sects" field
-  contains the value 15 or higher, as:
+  contains the value 15 or higher, as::
 
 	0x1c00  < 15*0x200 (= 0x1e00) but
 	0x1c00 >= 14*0x200 (= 0x1c00)
 
-	0x1c00 >> 9 = 14, so the minimum value for setup_secs is 15.
+	0x1c00 >> 9 = 14, So the minimum value for setup_secs is 15.
 
+============	==================
 Field name:	type_of_loader
 Type:		write (obligatory)
 Offset/size:	0x210/1
 Protocol:	2.00+
+============	==================
 
   If your boot loader has an assigned id (see table below), enter
   0xTV here, where T is an identifier for the boot loader and V is
@@ -369,17 +406,20 @@ Protocol:	2.00+
   Similarly, the ext_loader_ver field can be used to provide more than
   four bits for the bootloader version.
 
-  For example, for T = 0x15, V = 0x234, write:
+  For example, for T = 0x15, V = 0x234, write::
 
-  type_of_loader  <- 0xE4
-  ext_loader_type <- 0x05
-  ext_loader_ver  <- 0x23
+	type_of_loader  <- 0xE4
+	ext_loader_type <- 0x05
+	ext_loader_ver  <- 0x23
 
   Assigned boot loader ids (hexadecimal):
 
-	0  LILO			(0x00 reserved for pre-2.00 bootloader)
+	== =======================================
+	0  LILO
+	   (0x00 reserved for pre-2.00 bootloader)
 	1  Loadlin
-	2  bootsect-loader	(0x20, all other values reserved)
+	2  bootsect-loader
+	   (0x20, all other values reserved)
 	3  Syslinux
 	4  Etherboot/gPXE/iPXE
 	5  ELILO
@@ -390,55 +430,70 @@ Protocol:	2.00+
 	B  Qemu
 	C  Arcturus Networks uCbootloader
 	D  kexec-tools
-	E  Extended		(see ext_loader_type)
-	F  Special		(0xFF = undefined)
-       10  Reserved
-       11  Minimal Linux Bootloader <http://sebastian-plotz.blogspot.de>
-       12  OVMF UEFI virtualization stack
+	E  Extended (see ext_loader_type)
+	F  Special (0xFF = undefined)
+	10 Reserved
+	11 Minimal Linux Bootloader
+	   <http://sebastian-plotz.blogspot.de>
+	12 OVMF UEFI virtualization stack
+	== =======================================
 
-  Please contact <hpa@zytor.com> if you need a bootloader ID
-  value assigned.
+  Please contact <hpa@zytor.com> if you need a bootloader ID value assigned.
 
+============	===================
 Field name:	loadflags
 Type:		modify (obligatory)
 Offset/size:	0x211/1
 Protocol:	2.00+
+============	===================
 
   This field is a bitmask.
 
   Bit 0 (read):	LOADED_HIGH
+
 	- If 0, the protected-mode code is loaded at 0x10000.
 	- If 1, the protected-mode code is loaded at 0x100000.
 
   Bit 1 (kernel internal): KASLR_FLAG
+
 	- Used internally by the compressed kernel to communicate
 	  KASLR status to kernel proper.
-	  If 1, KASLR enabled.
-	  If 0, KASLR disabled.
+
+	    - If 1, KASLR enabled.
+	    - If 0, KASLR disabled.
 
   Bit 5 (write): QUIET_FLAG
+
 	- If 0, print early messages.
 	- If 1, suppress early messages.
+
 		This requests to the kernel (decompressor and early
 		kernel) to not write early messages that require
 		accessing the display hardware directly.
 
   Bit 6 (write): KEEP_SEGMENTS
+
 	Protocol: 2.07+
+
 	- If 0, reload the segment registers in the 32bit entry point.
 	- If 1, do not reload the segment registers in the 32bit entry point.
+
 		Assume that %cs %ds %ss %es are all set to flat segments with
 		a base of 0 (or the equivalent for their environment).
 
   Bit 7 (write): CAN_USE_HEAP
+
 	Set this bit to 1 to indicate that the value entered in the
 	heap_end_ptr is valid.  If this field is clear, some setup code
 	functionality will be disabled.
 
+
+============	===================
 Field name:	setup_move_size
 Type:		modify (obligatory)
 Offset/size:	0x212/2
 Protocol:	2.00-2.01
+============	===================
 
   When using protocol 2.00 or 2.01, if the real mode kernel is not
   loaded at 0x90000, it gets moved there later in the loading
@@ -447,14 +502,16 @@ Protocol:	2.00-2.01
   itself.
 
   The unit is bytes starting with the beginning of the boot sector.
-  
+
   This field is can be ignored when the protocol is 2.02 or higher, or
   if the real-mode code is loaded at 0x90000.
 
+============	========================
 Field name:	code32_start
 Type:		modify (optional, reloc)
 Offset/size:	0x214/4
 Protocol:	2.00+
+============	========================
 
   The address to jump to in protected mode.  This defaults to the load
   address of the kernel, and can be used by the boot loader to
@@ -462,47 +519,57 @@ Protocol:	2.00+
 
   This field can be modified for two purposes:
 
-  1. as a boot loader hook (see ADVANCED BOOT LOADER HOOKS below.)
+    1. as a boot loader hook (see Advanced Boot Loader Hooks below.)
 
-  2. if a bootloader which does not install a hook loads a
-     relocatable kernel at a nonstandard address it will have to modify
-     this field to point to the load address.
+    2. if a bootloader which does not install a hook loads a
+       relocatable kernel at a nonstandard address it will have to modify
+       this field to point to the load address.
 
+============	==================
 Field name:	ramdisk_image
 Type:		write (obligatory)
 Offset/size:	0x218/4
 Protocol:	2.00+
+============	==================
 
   The 32-bit linear address of the initial ramdisk or ramfs.  Leave at
   zero if there is no initial ramdisk/ramfs.
 
+============	==================
 Field name:	ramdisk_size
 Type:		write (obligatory)
 Offset/size:	0x21c/4
 Protocol:	2.00+
+============	==================
 
   Size of the initial ramdisk or ramfs.  Leave at zero if there is no
   initial ramdisk/ramfs.
 
+============	===============
 Field name:	bootsect_kludge
 Type:		kernel internal
 Offset/size:	0x220/4
 Protocol:	2.00+
+============	===============
 
   This field is obsolete.
 
+============	==================
 Field name:	heap_end_ptr
 Type:		write (obligatory)
 Offset/size:	0x224/2
 Protocol:	2.01+
+============	==================
 
   Set this field to the offset (from the beginning of the real-mode
   code) of the end of the setup stack/heap, minus 0x0200.
 
+============	================
 Field name:	ext_loader_ver
 Type:		write (optional)
 Offset/size:	0x226/1
 Protocol:	2.02+
+============	================
 
   This field is used as an extension of the version number in the
   type_of_loader field.  The total version number is considered to be
@@ -514,10 +581,12 @@ Protocol:	2.02+
   Kernels prior to 2.6.31 did not recognize this field, but it is safe
   to write for protocol version 2.02 or higher.
 
+============	=====================================================
 Field name:	ext_loader_type
 Type:		write (obligatory if (type_of_loader & 0xf0) == 0xe0)
 Offset/size:	0x227/1
 Protocol:	2.02+
+============	=====================================================
 
   This field is used as an extension of the type number in
   type_of_loader field.  If the type in type_of_loader is 0xE, then
@@ -528,10 +597,12 @@ Protocol:	2.02+
   Kernels prior to 2.6.31 did not recognize this field, but it is safe
   to write for protocol version 2.02 or higher.
 
+============	==================
 Field name:	cmd_line_ptr
 Type:		write (obligatory)
 Offset/size:	0x228/4
 Protocol:	2.02+
+============	==================
 
   Set this field to the linear address of the kernel command line.
   The kernel command line can be located anywhere between the end of
@@ -544,10 +615,12 @@ Protocol:	2.02+
   zero, the kernel will assume that your boot loader does not support
   the 2.02+ protocol.
 
+============	===============
 Field name:	initrd_addr_max
 Type:		read
 Offset/size:	0x22c/4
 Protocol:	2.03+
+============	===============
 
   The maximum address that may be occupied by the initial
   ramdisk/ramfs contents.  For boot protocols 2.02 or earlier, this
@@ -556,10 +629,12 @@ Protocol:	2.03+
   your ramdisk is exactly 131072 bytes long and this field is
   0x37FFFFFF, you can start your ramdisk at 0x37FE0000.)
 
+============	============================
 Field name:	kernel_alignment
 Type:		read/modify (reloc)
 Offset/size:	0x230/4
 Protocol:	2.05+ (read), 2.10+ (modify)
+============	============================
 
   Alignment unit required by the kernel (if relocatable_kernel is
   true.)  A relocatable kernel that is loaded at an alignment
@@ -571,25 +646,29 @@ Protocol:	2.05+ (read), 2.10+ (modify)
   loader to modify this field to permit a lesser alignment.  See the
   min_alignment and pref_address field below.
 
+============	==================
 Field name:	relocatable_kernel
 Type:		read (reloc)
 Offset/size:	0x234/1
 Protocol:	2.05+
+============	==================
 
   If this field is nonzero, the protected-mode part of the kernel can
   be loaded at any address that satisfies the kernel_alignment field.
   After loading, the boot loader must set the code32_start field to
   point to the loaded code, or to a boot loader hook.
 
+============	=============
 Field name:	min_alignment
 Type:		read (reloc)
 Offset/size:	0x235/1
 Protocol:	2.10+
+============	=============
 
   This field, if nonzero, indicates as a power of two the minimum
   alignment required, as opposed to preferred, by the kernel to boot.
   If a boot loader makes use of this field, it should update the
-  kernel_alignment field with the alignment unit desired; typically:
+  kernel_alignment field with the alignment unit desired; typically::
 
 	kernel_alignment = 1 << min_alignment
 
@@ -597,44 +676,56 @@ Protocol:	2.10+
   misaligned kernel.  Therefore, a loader should typically try each
   power-of-two alignment from kernel_alignment down to this alignment.
 
-Field name:     xloadflags
-Type:           read
-Offset/size:    0x236/2
-Protocol:       2.12+
+============	==========
+Field name:	xloadflags
+Type:		read
+Offset/size:	0x236/2
+Protocol:	2.12+
+============	==========
 
   This field is a bitmask.
 
   Bit 0 (read):	XLF_KERNEL_64
+
 	- If 1, this kernel has the legacy 64-bit entry point at 0x200.
 
   Bit 1 (read): XLF_CAN_BE_LOADED_ABOVE_4G
+
         - If 1, kernel/boot_params/cmdline/ramdisk can be above 4G.
 
   Bit 2 (read):	XLF_EFI_HANDOVER_32
+
 	- If 1, the kernel supports the 32-bit EFI handoff entry point
           given at handover_offset.
 
   Bit 3 (read): XLF_EFI_HANDOVER_64
+
 	- If 1, the kernel supports the 64-bit EFI handoff entry point
           given at handover_offset + 0x200.
 
   Bit 4 (read): XLF_EFI_KEXEC
+
 	- If 1, the kernel supports kexec EFI boot with EFI runtime support.
 
+
+============	============
 Field name:	cmdline_size
 Type:		read
 Offset/size:	0x238/4
 Protocol:	2.06+
+============	============
 
   The maximum size of the command line without the terminating
   zero. This means that the command line can contain at most
   cmdline_size characters. With protocol version 2.05 and earlier, the
   maximum size was 255.
 
+============	====================================
 Field name:	hardware_subarch
 Type:		write (optional, defaults to x86/PC)
 Offset/size:	0x23c/4
 Protocol:	2.07+
+============	====================================
 
   In a paravirtualized environment the hardware low level architectural
   pieces such as interrupt handling, page table handling, and
@@ -643,25 +734,31 @@ Protocol:	2.07+
   This field allows the bootloader to inform the kernel we are in one
   one of those environments.
 
+  ==========	==============================
   0x00000000	The default x86/PC environment
   0x00000001	lguest
   0x00000002	Xen
   0x00000003	Moorestown MID
   0x00000004	CE4100 TV Platform
+  ==========	==============================
 
+============	=========================
 Field name:	hardware_subarch_data
 Type:		write (subarch-dependent)
 Offset/size:	0x240/8
 Protocol:	2.07+
+============	=========================
 
   A pointer to data that is specific to hardware subarch
   This field is currently unused for the default x86/PC environment,
   do not modify.
 
+============	==============
 Field name:	payload_offset
 Type:		read
 Offset/size:	0x248/4
 Protocol:	2.08+
+============	==============
 
   If non-zero then this field contains the offset from the beginning
   of the protected-mode code to the payload.
@@ -674,29 +771,33 @@ Protocol:	2.08+
   02 21).  The uncompressed payload is currently always ELF (magic
   number 7F 45 4C 46).
 
+============	==============
 Field name:	payload_length
 Type:		read
 Offset/size:	0x24c/4
 Protocol:	2.08+
+============	==============
 
   The length of the payload.
 
+============	===============
 Field name:	setup_data
 Type:		write (special)
 Offset/size:	0x250/8
 Protocol:	2.09+
+============	===============
 
   The 64-bit physical pointer to NULL terminated single linked list of
   struct setup_data. This is used to define a more extensible boot
   parameters passing mechanism. The definition of struct setup_data is
-  as follow:
+  as follow::
 
-  struct setup_data {
-	  u64 next;
-	  u32 type;
-	  u32 len;
-	  u8  data[0];
-  };
+	struct setup_data {
+		u64 next;
+		u32 type;
+		u32 len;
+		u8  data[0];
+	};
 
   Where, the next is a 64-bit physical pointer to the next node of
   linked list, the next field of the last node is 0; the type is used
@@ -708,10 +809,12 @@ Protocol:	2.09+
   sure to consider the case where the linked list already contains
   entries.
 
+============	============
 Field name:	pref_address
 Type:		read (reloc)
 Offset/size:	0x258/8
 Protocol:	2.10+
+============	============
 
   This field, if nonzero, represents a preferred load address for the
   kernel.  A relocating bootloader should attempt to load at this
@@ -720,9 +823,11 @@ Protocol:	2.10+
   A non-relocatable kernel will unconditionally move itself and to run
   at this address.
 
+============	=======
 Field name:	init_size
 Type:		read
 Offset/size:	0x260/4
+============	=======
 
   This field indicates the amount of linear contiguous memory starting
   at the kernel runtime start address that the kernel needs before it
@@ -731,16 +836,18 @@ Offset/size:	0x260/4
   be used by a relocating boot loader to help select a safe load
   address for the kernel.
 
-  The kernel runtime start address is determined by the following algorithm:
+  The kernel runtime start address is determined by the following algorithm::
 
-  if (relocatable_kernel)
+	if (relocatable_kernel)
 	runtime_start = align_up(load_address, kernel_alignment)
-  else
+	else
 	runtime_start = pref_address
 
+============	===============
 Field name:	handover_offset
 Type:		read
 Offset/size:	0x264/4
+============	===============
 
   This field is the offset from the beginning of the kernel image to
   the EFI handover protocol entry point. Boot loaders using the EFI
@@ -749,7 +856,8 @@ Offset/size:	0x264/4
   See EFI HANDOVER PROTOCOL below for more details.
 
 
-**** THE IMAGE CHECKSUM
+The Image Checksum
+==================
 
 From boot protocol version 2.08 onwards the CRC-32 is calculated over
 the entire file using the characteristic polynomial 0x04C11DB7 and an
@@ -758,7 +866,8 @@ file; therefore the CRC of the file up to the limit specified in the
 syssize field of the header is always 0.
 
 
-**** THE KERNEL COMMAND LINE
+The Kernel Command Line
+=======================
 
 The kernel command line has become an important way for the boot
 loader to communicate with the kernel.  Some of its options are also
@@ -778,19 +887,20 @@ heap and 0xA0000.
 If the protocol version is *not* 2.02 or higher, the kernel
 command line is entered using the following protocol:
 
-	At offset 0x0020 (word), "cmd_line_magic", enter the magic
-	number 0xA33F.
+  - At offset 0x0020 (word), "cmd_line_magic", enter the magic
+    number 0xA33F.
+
+  - At offset 0x0022 (word), "cmd_line_offset", enter the offset
+    of the kernel command line (relative to the start of the
+    real-mode kernel).
 
-	At offset 0x0022 (word), "cmd_line_offset", enter the offset
-	of the kernel command line (relative to the start of the
-	real-mode kernel).
-	
-	The kernel command line *must* be within the memory region
-	covered by setup_move_size, so you may need to adjust this
-	field.
+  - The kernel command line *must* be within the memory region
+    covered by setup_move_size, so you may need to adjust this
+    field.
 
 
-**** MEMORY LAYOUT OF THE REAL-MODE CODE
+Memory Layout of The Real-Mode Code
+===================================
 
 The real-mode code requires a stack/heap to be set up, as well as
 memory allocated for the kernel command line.  This needs to be done
@@ -806,10 +916,11 @@ segment has to be used:
 	- When loading a zImage kernel ((loadflags & 0x01) == 0).
 	- When loading a 2.01 or earlier boot protocol kernel.
 
-	  -> For the 2.00 and 2.01 boot protocols, the real-mode code
-	     can be loaded at another address, but it is internally
-	     relocated to 0x90000.  For the "old" protocol, the
-	     real-mode code must be loaded at 0x90000.
+.. note::
+     For the 2.00 and 2.01 boot protocols, the real-mode code
+     can be loaded at another address, but it is internally
+     relocated to 0x90000.  For the "old" protocol, the
+     real-mode code must be loaded at 0x90000.
 
 When loading at 0x90000, avoid using memory above 0x9a000.
 
@@ -822,24 +933,29 @@ The kernel command line should not be located below the real-mode
 code, nor should it be located in high memory.
 
 
-**** SAMPLE BOOT CONFIGURATION
+Sample Boot Configuartion
+=========================
 
 As a sample configuration, assume the following layout of the real
-mode segment:
+mode segment.
 
     When loading below 0x90000, use the entire segment:
 
+        =============	===================
 	0x0000-0x7fff	Real mode kernel
 	0x8000-0xdfff	Stack and heap
 	0xe000-0xffff	Kernel command line
+	=============	===================
 
     When loading at 0x90000 OR the protocol version is 2.01 or earlier:
 
+	=============	===================
 	0x0000-0x7fff	Real mode kernel
 	0x8000-0x97ff	Stack and heap
 	0x9800-0x9fff	Kernel command line
+	=============	===================
 
-Such a boot loader should enter the following fields in the header:
+Such a boot loader should enter the following fields in the header::
 
 	unsigned long base_ptr;	/* base address for real-mode segment */
 
@@ -898,7 +1014,8 @@ Such a boot loader should enter the following fields in the header:
 	}
 
 
-**** LOADING THE REST OF THE KERNEL
+Loading The Rest of The Kernel
+==============================
 
 The 32-bit (non-real-mode) kernel starts at offset (setup_sects+1)*512
 in the kernel file (again, if setup_sects == 0 the real value is 4.)
@@ -906,7 +1023,7 @@ It should be loaded at address 0x10000 for Image/zImage kernels and
 0x100000 for bzImage kernels.
 
 The kernel is a bzImage kernel if the protocol >= 2.00 and the 0x01
-bit (LOAD_HIGH) in the loadflags field is set:
+bit (LOAD_HIGH) in the loadflags field is set::
 
 	is_bzImage = (protocol >= 0x0200) && (loadflags & 0x01);
 	load_address = is_bzImage ? 0x100000 : 0x10000;
@@ -916,8 +1033,8 @@ the entire 0x10000-0x90000 range of memory.  This means it is pretty
 much a requirement for these kernels to load the real-mode part at
 0x90000.  bzImage kernels allow much more flexibility.
 
-
-**** SPECIAL COMMAND LINE OPTIONS
+Special Command Line Options
+============================
 
 If the command line provided by the boot loader is entered by the
 user, the user may expect the following command line options to work.
@@ -966,7 +1083,8 @@ or configuration-specified command line.  Otherwise, "init=/bin/sh"
 gets confused by the "auto" option.
 
 
-**** RUNNING THE KERNEL
+Running the Kernel
+==================
 
 The kernel is started by jumping to the kernel entry point, which is
 located at *segment* offset 0x20 from the start of the real mode
@@ -980,7 +1098,7 @@ interrupts should be disabled.  Furthermore, to guard against bugs in
 the kernel, it is recommended that the boot loader sets fs = gs = ds =
 es = ss.
 
-In our example from above, we would do:
+In our example from above, we would do::
 
 	/* Note: in the case of the "old" kernel protocol, base_ptr must
 	   be == 0x90000 at this point; see the previous sample code */
@@ -1003,7 +1121,8 @@ switched off, especially if the loaded kernel has the floppy driver as
 a demand-loaded module!
 
 
-**** ADVANCED BOOT LOADER HOOKS
+Advanced Boot Loader Hooks
+==========================
 
 If the boot loader runs in a particularly hostile environment (such as
 LOADLIN, which runs under DOS) it may be impossible to follow the
@@ -1032,7 +1151,8 @@ IMPORTANT: All the hooks are required to preserve %esp, %ebp, %esi and
 	(relocated, if appropriate.)
 
 
-**** 32-bit BOOT PROTOCOL
+32-bit Boot Protocol
+====================
 
 For machine with some new BIOS other than legacy BIOS, such as EFI,
 LinuxBIOS, etc, and kexec, the 16-bit real mode setup code in kernel
@@ -1045,7 +1165,7 @@ traditionally known as "zero page"). The memory for struct boot_params
 should be allocated and initialized to all zero. Then the setup header
 from offset 0x01f1 of kernel image on should be loaded into struct
 boot_params and examined. The end of setup header can be calculated as
-follow:
+follow::
 
 	0x0202 + byte value at offset 0x0201
 
@@ -1069,7 +1189,8 @@ must have read/write permission; CS must be __BOOT_CS and DS, ES, SS
 must be __BOOT_DS; interrupt must be disabled; %esi must hold the base
 address of the struct boot_params; %ebp, %edi and %ebx must be zero.
 
-**** 64-bit BOOT PROTOCOL
+64-bit Boot Protocol
+====================
 
 For machine with 64bit cpus and 64bit kernel, we could use 64bit bootloader
 and we need a 64-bit boot protocol.
@@ -1080,7 +1201,7 @@ traditionally known as "zero page"). The memory for struct boot_params
 could be allocated anywhere (even above 4G) and initialized to all zero.
 Then, the setup header at offset 0x01f1 of kernel image on should be
 loaded into struct boot_params and examined. The end of setup header
-can be calculated as follows:
+can be calculated as follows::
 
 	0x0202 + byte value at offset 0x0201
 
@@ -1107,7 +1228,8 @@ must have read/write permission; CS must be __BOOT_CS and DS, ES, SS
 must be __BOOT_DS; interrupt must be disabled; %rsi must hold the base
 address of the struct boot_params.
 
-**** EFI HANDOVER PROTOCOL
+EFI Handover Protocol
+=====================
 
 This protocol allows boot loaders to defer initialisation to the EFI
 boot stub. The boot loader is required to load the kernel/initrd(s)
@@ -1115,7 +1237,7 @@ from the boot media and jump to the EFI handover protocol entry point
 which is hdr->handover_offset bytes from the beginning of
 startup_{32,64}.
 
-The function prototype for the handover entry point looks like this,
+The function prototype for the handover entry point looks like this::
 
     efi_main(void *handle, efi_system_table_t *table, struct boot_params *bp)
 
@@ -1124,11 +1246,11 @@ firmware, 'table' is the EFI system table - these are the first two
 arguments of the "handoff state" as described in section 2.3 of the
 UEFI specification. 'bp' is the boot loader-allocated boot params.
 
-The boot loader *must* fill out the following fields in bp,
+The boot loader *must* fill out the following fields in bp::
 
-    o hdr.code32_start
-    o hdr.cmd_line_ptr
-    o hdr.ramdisk_image (if applicable)
-    o hdr.ramdisk_size  (if applicable)
+  - hdr.code32_start
+  - hdr.cmd_line_ptr
+  - hdr.ramdisk_image (if applicable)
+  - hdr.ramdisk_size  (if applicable)
 
 All other fields should be zero.
diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst
index 9f34545a9c52..d7fc8efac192 100644
--- a/Documentation/x86/index.rst
+++ b/Documentation/x86/index.rst
@@ -7,3 +7,5 @@ x86-specific Documentation
 .. toctree::
    :maxdepth: 2
    :numbered:
+
+   boot
-- 
2.20.1