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@xxxxxxxxxxxx> --- Makefile | 5 +++++ lib/Kconfig.debug | 30 ++++++++++++++++++++++++++++++ scripts/Makefile.build | 9 +++++++-- 3 files changed, 42 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index e518ed6..1f22c1f 100644 --- a/Makefile +++ b/Makefile @@ -520,6 +520,11 @@ KBUILD_CFLAGS += -g KBUILD_AFLAGS += -gdwarf-2 endif +# We trigger additional mismatches with less inlining +ifdef CONFIG_DEBUG_SECTION_MISMATCH +KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once) +endif + # Force gcc to behave correct even for buggy distributions KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a601093..c1fb0c6 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -79,6 +79,36 @@ config HEADERS_CHECK exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in your build tree), to make sure they're suitable. +config DEBUG_SECTION_MISMATCH + bool "Enable full Section mismatch analysis" + default y + help + The section mismatch analysis checks if there are illegal + references from one section to another section. + Linux will during link or during runtime drop some sections + and any use of code/data previously in these sections will + most likely result in an oops. + In the code functions and variables are annotated with + __init, __devinit etc. (see full list in include/linux/init.h) + which result in the code/data being placed in specific sections. + The section mismatch anaylsis are always done after a full + kernel build but enabling this options will in addition + do the following: + - Add the option -fno-inline-functions-called-once to gcc + When inlining a function annotated __init in a non-init + function we would loose the section information and thus + the analysis would not catch the illegal reference. + This options tell gcc to inline less but will also + result in a larger kernel. + - Run the section mismatch analysis for each module/built-in.o + When we run the section mismatch analysis on vmlinux.o we + looses valueable information about where the mismatch was + introduced. + Running the analysis for each module/built-in.o file + will tell where the mismatch happens much closer to the + source. The drawback is that we will report the same + mismatch at least twice. + config DEBUG_KERNEL bool "Kernel debugging" help diff --git a/scripts/Makefile.build b/scripts/Makefile.build index db38ef4..67fb453 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -103,6 +103,10 @@ ifneq ($(KBUILD_CHECKSRC),0) endif endif +# Do section mismatch analysis for each module/built-in.o +ifdef CONFIG_DEBUG_SECTION_MISMATCH + cmd_secanalysis = ; scripts/mod/modpost $@ +endif # Compile C sources (.c) # --------------------------------------------------------------------------- @@ -268,7 +272,8 @@ ifdef builtin-target quiet_cmd_link_o_target = LD $@ # If the list of objects to link is empty, just create an empty built-in.o cmd_link_o_target = $(if $(strip $(obj-y)),\ - $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^),\ + $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \ + $(cmd_secanalysis),\ rm -f $@; $(AR) rcs $@) $(builtin-target): $(obj-y) FORCE @@ -316,7 +321,7 @@ $($(subst $(obj)/,,$(@:.o=-objs))) \ $($(subst $(obj)/,,$(@:.o=-y)))), $^) quiet_cmd_link_multi-y = LD $@ -cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) +cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) quiet_cmd_link_multi-m = LD [M] $@ cmd_link_multi-m = $(cmd_link_multi-y) -- 1.5.4.rc3.14.g44397 - To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
