Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next

* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next:
  kbuild: ignore a few files in headers_check
  kbuild: add checks for include of linux/types in userspace headers
  kbuild: drop debugging leftover in tags.sh
  kbuild: document environment variables
  kbuild: make *config usage docs
  kbuild: disable sparse warning "returning void-valued expression"
  kbuild: in headers_install autoconvert asm/inline/volatile to __xxx__
  kbuild: check for leaked CONFIG_ symbols to userspace
  headers_check.pl: disallow extern's
  kconfig: improve error messages for bad source statements
  kconfig: struct property commented
  kconfig: add comments to symbol flags
  kconfig: explain symbol value defaults
  m68k: fix recursive dependency in Kconfig

3 files changed, 319 insertions, 1 deletions

diff --git a/Documentation/kbuild/00-INDEX b/Documentation/kbuild/00-INDEX
index 114644285454..e8d2b6d83a3d 100644
--- a/Documentation/kbuild/00-INDEX
+++ b/Documentation/kbuild/00-INDEX
@@ -1,5 +1,9 @@
 00-INDEX
-        - this file: info on the kernel build process
+        - this file: info on the kernel build process
+kbuild.txt
+        - developer information on kbuild
+kconfig.txt
+        - usage help for make *config
 kconfig-language.txt
         - specification of Config Language, the language in Kconfig files
 makefiles.txt
diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
new file mode 100644
index 000000000000..51771847e816
--- /dev/null
+++ b/Documentation/kbuild/kbuild.txt
@@ -0,0 +1,126 @@
+Environment variables
+
+KCPPFLAGS
+--------------------------------------------------
+Additional options to pass when preprocessing. The preprocessing options
+will be used in all cases where kbuild do preprocessing including
+building C files and assembler files.
+
+KAFLAGS
+--------------------------------------------------
+Additional options to the assembler.
+
+KCFLAGS
+--------------------------------------------------
+Additional options to the C compiler.
+
+KBUILD_VERBOSE
+--------------------------------------------------
+Set the kbuild verbosity. Can be assinged 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.
+The directory can be specified in several ways:
+1) Use "M=..." on the command line
+2) Environmnet variable KBUILD_EXTMOD
+3) Environmnet variable SUBDIRS
+The possibilities are listed in the order they take precedence.
+Using "M=..." will always override the others.
+
+KBUILD_OUTPUT
+--------------------------------------------------
+Specify the output directory when building the kernel.
+The output directory can also be specificed using "O=...".
+Setting "O=..." takes precedence over KBUILD_OUTPUT
+
+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 suach as x86 and sparc has aliases.
+x86: i386 for 32 bit, x86_64 for 64 bit
+sparc: sparc 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 is 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
+
+
+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 will used as the options to the strip command.
+
+INSTALL_FW_PATH
+--------------------------------------------------
+INSTALL_FW_PATH specify where to install the firmware blobs.
+The default value is:
+
+    $(INSTALL_MOD_PATH)/lib/firmware
+
+The value can be overridden in which case the default value is ignored.
+
+INSTALL_HDR_PATH
+--------------------------------------------------
+INSTALL_HDR_PATH specify 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_MODPOST_WARN
+--------------------------------------------------
+KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
+symbols in the final module linking stage.
+
+KBUILD_MODPOST_FINAL
+--------------------------------------------------
+KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
+This is solely usefull to speed up test compiles.
+
+KBUILD_EXTRA_SYMBOLS
+--------------------------------------------------
+For modules use symbols from another modules.
+See more details in modules.txt.
diff --git a/Documentation/kbuild/kconfig.txt b/Documentation/kbuild/kconfig.txt
new file mode 100644
index 000000000000..26a7c0a93193
--- /dev/null
+++ b/Documentation/kbuild/kconfig.txt
@@ -0,0 +1,188 @@
+This file contains some assistance for using "make *config".
+
+Use "make help" to list all of the possible configuration targets.
+
+The xconfig ('qconf') and menuconfig ('mconf') programs also
+have embedded help text.  Be sure to check it for navigation,
+search, and other general help text.
+
+======================================================================
+General
+--------------------------------------------------
+
+New kernel releases often introduce new config symbols.  Often more
+important, new kernel releases may rename config symbols.  When
+this happens, using a previously working .config file and running
+"make oldconfig" won't necessarily produce a working new kernel
+for you, so you may find that you need to see what NEW kernel
+symbols have been introduced.
+
+To see a list of new config symbols when using "make oldconfig", use
+
+        cp user/some/old.config .config
+        yes "" | make oldconfig >conf.new
+
+and the config program will list as (NEW) any new symbols that have
+unknown values.  Of course, the .config file is also updated with
+new (default) values, so you can use:
+
+        grep "(NEW)" conf.new
+
+to see the new config symbols or you can 'diff' the previous and
+new .config files to see the differences:
+
+        diff .config.old .config | less
+
+(Yes, we need something better here.)
+
+
+======================================================================
+menuconfig
+--------------------------------------------------
+
+SEARCHING for CONFIG symbols
+
+Searching in menuconfig:
+
+        The Search function searches for kernel configuration symbol
+        names, so you have to know something close to what you are
+        looking for.
+
+        Example:
+                /hotplug
+                This lists all config symbols that contain "hotplug",
+                e.g., HOTPLUG, HOTPLUG_CPU, MEMORY_HOTPLUG.
+
+        For search help, enter / followed TAB-TAB-TAB (to highlight
+        <Help>) and Enter.  This will tell you that you can also use
+        regular expressions (regexes) in the search string, so if you
+        are not interested in MEMORY_HOTPLUG, you could try
+
+                /^hotplug
+
+
+______________________________________________________________________
+Color Themes for 'menuconfig'
+
+It is possible to select different color themes using the variable
+MENUCONFIG_COLOR.  To select a theme use:
+
+        make MENUCONFIG_COLOR=<theme> menuconfig
+
+Available themes are:
+  mono       => selects colors suitable for monochrome displays
+  blackbg    => selects a color scheme with black background
+  classic    => theme with blue background. The classic look
+  bluetitle  => a LCD friendly version of classic. (default)
+
+______________________________________________________________________
+Environment variables in 'menuconfig'
+
+KCONFIG_ALLCONFIG
+--------------------------------------------------
+(partially based on lkml email from/by Rob Landley, re: miniconfig)
+--------------------------------------------------
+The allyesconfig/allmodconfig/allnoconfig/randconfig variants can
+also use the environment variable KCONFIG_ALLCONFIG as a flag or a
+filename that contains config symbols that the user requires to be
+set to a specific value.  If KCONFIG_ALLCONFIG is used without a
+filename, "make *config" checks for a file named
+"all{yes/mod/no/random}.config" (corresponding to the *config command
+that was used) for symbol values that are to be forced.  If this file
+is not found, it checks for a file named "all.config" to contain forced
+values.
+
+This enables you to create "miniature" config (miniconfig) or custom
+config files containing just the config symbols that you are interested
+in.  Then the kernel config system generates the full .config file,
+including dependencies of your miniconfig file, based on the miniconfig
+file.
+
+This 'KCONFIG_ALLCONFIG' file is a config file which contains
+(usually a subset of all) preset config symbols.  These variable
+settings are still subject to normal dependency checks.
+
+Examples:
+        KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
+or
+        KCONFIG_ALLCONFIG=mini.config make allnoconfig
+or
+        make KCONFIG_ALLCONFIG=mini.config allnoconfig
+
+These examples will disable most options (allnoconfig) but enable or
+disable the options that are explicitly listed in the specified
+mini-config files.
+
+KCONFIG_NOSILENTUPDATE
+--------------------------------------------------
+If this variable has a non-blank value, it prevents silent kernel
+config udpates (requires explicit updates).
+
+KCONFIG_CONFIG
+--------------------------------------------------
+This environment variable can be used to specify a default kernel config
+file name to override the default name of ".config".
+
+KCONFIG_OVERWRITECONFIG
+--------------------------------------------------
+If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
+break symlinks when .config is a symlink to somewhere else.
+
+KCONFIG_NOTIMESTAMP
+--------------------------------------------------
+If this environment variable exists and is non-null, the timestamp line
+in generated .config files is omitted.
+
+KCONFIG_AUTOCONFIG
+--------------------------------------------------
+This environment variable can be set to specify the path & name of the
+"auto.conf" file.  Its default value is "include/config/auto.conf".
+
+KCONFIG_AUTOHEADER
+--------------------------------------------------
+This environment variable can be set to specify the path & name of the
+"autoconf.h" (header) file.  Its default value is "include/linux/autoconf.h".
+
+______________________________________________________________________
+menuconfig User Interface Options
+----------------------------------------------------------------------
+MENUCONFIG_MODE
+--------------------------------------------------
+This mode shows all sub-menus in one large tree.
+
+Example:
+        MENUCONFIG_MODE=single_menu make menuconfig
+
+======================================================================
+xconfig
+--------------------------------------------------
+
+Searching in xconfig:
+
+        The Search function searches for kernel configuration symbol
+        names, so you have to know something close to what you are
+        looking for.
+
+        Example:
+                Ctrl-F hotplug
+        or
+                Menu: File, Search, hotplug
+
+        lists all config symbol entries that contain "hotplug" in
+        the symbol name.  In this Search dialog, you may change the
+        config setting for any of the entries that are not grayed out.
+        You can also enter a different search string without having
+        to return to the main menu.
+
+
+======================================================================
+gconfig
+--------------------------------------------------
+
+Searching in gconfig:
+
+        None (gconfig isn't maintained as well as xconfig or menuconfig);
+        however, gconfig does have a few more viewing choices than
+        xconfig does.
+
+###