kbuild: introduce new option to enhance section mismatch analysis
Setting the option DEBUG_SECTION_MISMATCH will
report additional section mismatch'es but this
should in the end makes it possible to get rid of
all of them.
See help text in lib/Kconfig.debug for details.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 14fb355..748e72b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -79,6 +79,36 @@
exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
your build tree), to make sure they're suitable.
+config DEBUG_SECTION_MISMATCH
+ bool "Enable full Section mismatch analysis"
+ default n
+ help
+ The section mismatch analysis checks if there are illegal
+ references from one section to another section.
+ Linux will during link or during runtime drop some sections
+ and any use of code/data previously in these sections will
+ most likely result in an oops.
+ In the code functions and variables are annotated with
+ __init, __devinit etc. (see full list in include/linux/init.h)
+ which result in the code/data being placed in specific sections.
+ The section mismatch anaylsis are always done after a full
+ kernel build but enabling this options will in addition
+ do the following:
+ - Add the option -fno-inline-functions-called-once to gcc
+ When inlining a function annotated __init in a non-init
+ function we would loose the section information and thus
+ the analysis would not catch the illegal reference.
+ This options tell gcc to inline less but will also
+ result in a larger kernel.
+ - Run the section mismatch analysis for each module/built-in.o
+ When we run the section mismatch analysis on vmlinux.o we
+ looses valueable information about where the mismatch was
+ introduced.
+ Running the analysis for each module/built-in.o file
+ will tell where the mismatch happens much closer to the
+ source. The drawback is that we will report the same
+ mismatch at least twice.
+
config DEBUG_KERNEL
bool "Kernel debugging"
help