docs: move x86 documentation into Documentation/arch/

JIRA: https://issues.redhat.com/browse/RHEL-15513

Conflicts:
    This is a partial backport of the referenced upstream commit
    that just includes the move of Documentation/x86/boot.rst
    to Documentation/arch/x86/boot.rst and its in-kernel references.

    Additionally, since Documentation/x86/index.rst has not been
    moved, its reference to boot.rst is updated to its new location.

commit ff61f07
Author: Jonathan Corbet <corbet@lwn.net>
Date:   Tue Mar 14 17:06:44 2023 -0600

    docs: move x86 documentation into Documentation/arch/

    Move the x86 documentation under Documentation/arch/ as a way of cleaning
    up the top-level directory and making the structure of our docs more
    closely match the structure of the source directories it describes.

    All in-kernel references to the old paths have been updated.

    Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: linux-arch@vger.kernel.org
    Cc: x86@kernel.org
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/
    Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>

Author: LennySzubowicz

Documentation/admin-guide/kernel-parameters.rst

@@ -196,7 +196,7 @@ In addition, the following text indicates that the option::
 Parameters denoted with BOOT are actually interpreted by the boot
 loader, and have no meaning to the kernel directly.
 Do not modify the syntax of boot loader parameters without extreme
-need or coordination with <Documentation/x86/boot.rst>.
+need or coordination with <Documentation/arch/x86/boot.rst>.
 
 There are also arch-specific kernel-parameters not documented here.
 See for example <Documentation/x86/x86_64/boot-options.rst>.

Documentation/admin-guide/kernel-parameters.txt

@@ -6680,7 +6680,7 @@
 			Can be used multiple times for multiple devices.
 
 	vga=		[BOOT,X86-32] Select a particular video mode
-			See Documentation/x86/boot.rst and
+			See Documentation/arch/x86/boot.rst and
 			Documentation/admin-guide/svga.rst.
 			Use vga=ask for menu.
 			This is actually a boot loader parameter; the value is

Documentation/admin-guide/sysctl/kernel.rst

@@ -90,7 +90,7 @@ is 0x15 and the full version number is 0x234, this file will contain
 the value 340 = 0x154.
 
 See the ``type_of_loader`` and ``ext_loader_type`` fields in
-Documentation/x86/boot.rst for additional information.
+Documentation/arch/x86/boot.rst for additional information.
 
 
 bootloader_version (x86 only)
@@ -100,7 +100,7 @@ The complete bootloader version number.  In the example above, this
 file will contain the value 564 = 0x234.
 
 See the ``type_of_loader`` and ``ext_loader_ver`` fields in
-Documentation/x86/boot.rst for additional information.
+Documentation/arch/x86/boot.rst for additional information.
 
 
 bpf_stats_enabled

Documentation/x86/boot.rst renamed to Documentation/arch/x86/boot.rst

@@ -7,7 +7,7 @@ DeviceTree Booting
   the decompressor (the real mode entry point goes to the same  32bit
   entry point once it switched into protected mode). That entry point
   supports one calling convention which is documented in
-  Documentation/x86/boot.rst
+  Documentation/arch/x86/boot.rst
   The physical pointer to the device-tree block is passed via setup_data
   which requires at least boot protocol 2.09.
   The type filed is defined as

Documentation/x86/booting-dt.rst

@@ -8,7 +8,7 @@ x86-specific Documentation
    :maxdepth: 2
    :numbered:
 
-   boot
+   ../arch/x86/boot
    booting-dt
    cpuinfo
    topology

Documentation/x86/index.rst

@@ -321,7 +321,7 @@ start_sys_seg:	.word	SYSSEG		# obsolete and meaningless, but just
 
 type_of_loader:	.byte	0		# 0 means ancient bootloader, newer
 					# bootloaders know to change this.
-					# See Documentation/x86/boot.rst for
+					# See Documentation/arch/x86/boot.rst for
 					# assigned ids
 
 # flags, unused bits must be zero (RFU) bit within loadflags

arch/x86/boot/header.S

@@ -38,7 +38,7 @@ static void sanitize_boot_params(struct boot_params *boot_params)
 	 * IMPORTANT NOTE TO BOOTLOADER AUTHORS: do not simply clear
 	 * this field.  The purpose of this field is to guarantee
 	 * compliance with the x86 boot spec located in
-	 * Documentation/x86/boot.rst .  That spec says that the
+	 * Documentation/arch/x86/boot.rst .  That spec says that the
 	 * *whole* structure should be cleared, after which only the
 	 * portion defined by struct setup_header (boot_params->hdr)
 	 * should be copied in.

arch/x86/include/asm/bootparam_utils.h

@@ -408,7 +408,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
 	efi_map_offset = params_cmdline_sz;
 	efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
 
-	/* Copy setup header onto bootparams. Documentation/x86/boot.rst */
+	/* Copy setup header onto bootparams. Documentation/arch/x86/boot.rst */
 	setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
 
 	/* Is there a limit on setup header size? */

arch/x86/kernel/kexec-bzimage64.c

@@ -86,7 +86,7 @@ static void __init init_pvh_bootparams(bool xen_guest)
 	}
 
 	/*
-	 * See Documentation/x86/boot.rst.
+	 * See Documentation/arch/x86/boot.rst.
 	 *
 	 * Version 2.12 supports Xen entry point but we will use default x86/PC
 	 * environment (i.e. hardware_subarch 0).