[PATCH] Add CONFIG_HEADERS_CHECK option to automatically run 'make headers_check'

In order to encourage people to notice when they break the exported
headers, add a config option which automatically runs the sanity checks
when building vmlinux.  That way, those who use allyesconfig will notice
failures.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 16 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 274b780029b1..f242829c4f0b 100644
--- a/Makefile
+++ b/Makefile
@@ -741,6 +741,9 @@ endif # ifdef CONFIG_KALLSYMS
 
 # vmlinux image - including updated kernel symbols
 vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) $(kallsyms.o) FORCE
+ifdef CONFIG_HEADERS_CHECK
+        $(Q)$(MAKE) headers_check
+endif
         $(call if_changed_rule,vmlinux__)
         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost $@
         $(Q)rm -f .old_version
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2d7cb0d04fc8..8fd2dbf7eb5b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -371,6 +371,19 @@ config FORCED_INLINING
           become the default in the future, until then this option is there to
           test gcc for this.
 
+config HEADERS_CHECK
+        bool "Run 'make headers_check' when building vmlinux"
+        help
+          This option will extract the user-visible kernel headers whenever
+          building the kernel, and will run basic sanity checks on them to
+          ensure that exported files do not attempt to include files which
+          were not exported, etc.
+
+          If you're making modifications to header files which are
+          relevant for userspace, say 'Y', and check the headers
+          exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
+          your build tree), to make sure they're suitable.
+
 config RCU_TORTURE_TEST
         tristate "torture tests for RCU"
         depends on DEBUG_KERNEL