Merge tag 'docs-5.3' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:
 "It's been a relatively busy cycle for docs:

   - A fair pile of RST conversions, many from Mauro. These create more
     than the usual number of simple but annoying merge conflicts with
     other trees, unfortunately. He has a lot more of these waiting on
     the wings that, I think, will go to you directly later on.

   - A new document on how to use merges and rebases in kernel repos,
     and one on Spectre vulnerabilities.

   - Various improvements to the build system, including automatic
     markup of function() references because some people, for reasons I
     will never understand, were of the opinion that
     :c:func:``function()`` is unattractive and not fun to type.

   - We now recommend using sphinx 1.7, but still support back to 1.4.

   - Lots of smaller improvements, warning fixes, typo fixes, etc"

* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
  docs: automarkup.py: ignore exceptions when seeking for xrefs
  docs: Move binderfs to admin-guide
  Disable Sphinx SmartyPants in HTML output
  doc: RCU callback locks need only _bh, not necessarily _irq
  docs: format kernel-parameters -- as code
  Doc : doc-guide : Fix a typo
  platform: x86: get rid of a non-existent document
  Add the RCU docs to the core-api manual
  Documentation: RCU: Add TOC tree hooks
  Documentation: RCU: Rename txt files to rst
  Documentation: RCU: Convert RCU UP systems to reST
  Documentation: RCU: Convert RCU linked list to reST
  Documentation: RCU: Convert RCU basic concepts to reST
  docs: filesystems: Remove uneeded .rst extension on toctables
  scripts/sphinx-pre-install: fix out-of-tree build
  docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
  Documentation: PGP: update for newer HW devices
  Documentation: Add section about CPU vulnerabilities for Spectre
  Documentation: platform: Delete x86-laptop-drivers.txt
  docs: Note that :c:func: should no longer be used
  ...

1 files changed, 265 insertions, 0 deletions

diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
new file mode 100644
index 000000000000..e774e760522d
--- /dev/null
+++ b/Documentation/kbuild/kbuild.rst
@@ -0,0 +1,265 @@
+======
+Kbuild
+======
+
+
+Output files
+============
+
+modules.order
+-------------
+This file records the order in which modules appear in Makefiles. This
+is used by modprobe to deterministically resolve aliases that match
+multiple modules.
+
+modules.builtin
+---------------
+This file lists all modules that are built into the kernel. This is used
+by modprobe to not fail when trying to load something builtin.
+
+modules.builtin.modinfo
+--------------------------------------------------
+This file contains modinfo from all modules that are built into the kernel.
+Unlike modinfo of a separate module, all fields are prefixed with module name.
+
+
+Environment variables
+=====================
+
+KCPPFLAGS
+---------
+Additional options to pass when preprocessing. The preprocessing options
+will be used in all cases where kbuild does preprocessing including
+building C files and assembler files.
+
+KAFLAGS
+-------
+Additional options to the assembler (for built-in and modules).
+
+AFLAGS_MODULE
+-------------
+Additional module specific options to use for $(AS).
+
+AFLAGS_KERNEL
+-------------
+Additional options for $(AS) when used for assembler
+code for code that is compiled as built-in.
+
+KCFLAGS
+-------
+Additional options to the C compiler (for built-in and modules).
+
+CFLAGS_KERNEL
+-------------
+Additional options for $(CC) when used to compile
+code that is compiled as built-in.
+
+CFLAGS_MODULE
+-------------
+Additional module specific options to use for $(CC).
+
+LDFLAGS_MODULE
+--------------
+Additional options used for $(LD) when linking modules.
+
+HOSTCFLAGS
+----------
+Additional flags to be passed to $(HOSTCC) when building host programs.
+
+HOSTCXXFLAGS
+------------
+Additional flags to be passed to $(HOSTCXX) when building host programs.
+
+HOSTLDFLAGS
+-----------
+Additional flags to be passed when linking host programs.
+
+HOSTLDLIBS
+----------
+Additional libraries to link against when building host programs.
+
+KBUILD_KCONFIG
+--------------
+Set the top-level Kconfig file to the value of this environment
+variable.  The default name is "Kconfig".
+
+KBUILD_VERBOSE
+--------------
+Set the kbuild verbosity. Can be assigned same values as "V=...".
+
+See make help for the full list.
+
+Setting "V=..." takes precedence over KBUILD_VERBOSE.
+
+KBUILD_EXTMOD
+-------------
+Set the directory to look for the kernel source when building external
+modules.
+
+Setting "M=..." takes precedence over KBUILD_EXTMOD.
+
+KBUILD_OUTPUT
+-------------
+Specify the output directory when building the kernel.
+
+The output directory can also be specified using "O=...".
+
+Setting "O=..." takes precedence over KBUILD_OUTPUT.
+
+KBUILD_DEBARCH
+--------------
+For the deb-pkg target, allows overriding the normal heuristics deployed by
+deb-pkg. Normally deb-pkg attempts to guess the right architecture based on
+the UTS_MACHINE variable, and on some architectures also the kernel config.
+The value of KBUILD_DEBARCH is assumed (not checked) to be a valid Debian
+architecture.
+
+ARCH
+----
+Set ARCH to the architecture to be built.
+
+In most cases the name of the architecture is the same as the
+directory name found in the arch/ directory.
+
+But some architectures such as x86 and sparc have aliases.
+
+- x86: i386 for 32 bit, x86_64 for 64 bit
+- sh: sh for 32 bit, sh64 for 64 bit
+- sparc: sparc32 for 32 bit, sparc64 for 64 bit
+
+CROSS_COMPILE
+-------------
+Specify an optional fixed part of the binutils filename.
+CROSS_COMPILE can be a part of the filename or the full path.
+
+CROSS_COMPILE is also used for ccache in some setups.
+
+CF
+--
+Additional options for sparse.
+
+CF is often used on the command-line like this::
+
+    make CF=-Wbitwise C=2
+
+INSTALL_PATH
+------------
+INSTALL_PATH specifies where to place the updated kernel and system map
+images. Default is /boot, but you can set it to other values.
+
+INSTALLKERNEL
+-------------
+Install script called when using "make install".
+The default name is "installkernel".
+
+The script will be called with the following arguments:
+   - $1 - kernel version
+   - $2 - kernel image file
+   - $3 - kernel map file
+   - $4 - default install path (use root directory if blank)
+
+The implementation of "make install" is architecture specific
+and it may differ from the above.
+
+INSTALLKERNEL is provided to enable the possibility to
+specify a custom installer when cross compiling a kernel.
+
+MODLIB
+------
+Specify where to install modules.
+The default value is::
+
+     $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
+
+The value can be overridden in which case the default value is ignored.
+
+INSTALL_MOD_PATH
+----------------
+INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
+relocations required by build roots.  This is not defined in the
+makefile but the argument can be passed to make if needed.
+
+INSTALL_MOD_STRIP
+-----------------
+INSTALL_MOD_STRIP, if defined, will cause modules to be
+stripped after they are installed.  If INSTALL_MOD_STRIP is '1', then
+the default option --strip-debug will be used.  Otherwise,
+INSTALL_MOD_STRIP value will be used as the options to the strip command.
+
+INSTALL_HDR_PATH
+----------------
+INSTALL_HDR_PATH specifies where to install user space headers when
+executing "make headers_*".
+
+The default value is::
+
+    $(objtree)/usr
+
+$(objtree) is the directory where output files are saved.
+The output directory is often set using "O=..." on the commandline.
+
+The value can be overridden in which case the default value is ignored.
+
+KBUILD_SIGN_PIN
+---------------
+This variable allows a passphrase or PIN to be passed to the sign-file
+utility when signing kernel modules, if the private key requires such.
+
+KBUILD_MODPOST_WARN
+-------------------
+KBUILD_MODPOST_WARN can be set to avoid errors in case of undefined
+symbols in the final module linking stage. It changes such errors
+into warnings.
+
+KBUILD_MODPOST_NOFINAL
+----------------------
+KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
+This is solely useful to speed up test compiles.
+
+KBUILD_EXTRA_SYMBOLS
+--------------------
+For modules that use symbols from other modules.
+See more details in modules.txt.
+
+ALLSOURCE_ARCHS
+---------------
+For tags/TAGS/cscope targets, you can specify more than one arch
+to be included in the databases, separated by blank space. E.g.::
+
+    $ make ALLSOURCE_ARCHS="x86 mips arm" tags
+
+To get all available archs you can also specify all. E.g.::
+
+    $ make ALLSOURCE_ARCHS=all tags
+
+KBUILD_ENABLE_EXTRA_GCC_CHECKS
+------------------------------
+If enabled over the make command line with "W=1", it turns on additional
+gcc -W... options for more extensive build-time checking.
+
+KBUILD_BUILD_TIMESTAMP
+----------------------
+Setting this to a date string overrides the timestamp used in the
+UTS_VERSION definition (uname -v in the running kernel). The value has to
+be a string that can be passed to date -d. The default value
+is the output of the date command at one point during build.
+
+KBUILD_BUILD_USER, KBUILD_BUILD_HOST
+------------------------------------
+These two variables allow to override the user@host string displayed during
+boot and in /proc/version. The default value is the output of the commands
+whoami and host, respectively.
+
+KBUILD_LDS
+----------
+The linker script with full path. Assigned by the top-level Makefile.
+
+KBUILD_VMLINUX_OBJS
+-------------------
+All object files for vmlinux. They are linked to vmlinux in the same
+order as listed in KBUILD_VMLINUX_OBJS.
+
+KBUILD_VMLINUX_LIBS
+-------------------
+All .a "lib" files for vmlinux. KBUILD_VMLINUX_OBJS and KBUILD_VMLINUX_LIBS
+together specify all the object files used to link vmlinux.