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Commit b9ab5ebb authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
Browse files

objtool: Add CONFIG_STACK_VALIDATION option 



Add a CONFIG_STACK_VALIDATION option which will run "objtool check" for
each .o file to ensure the validity of its stack metadata.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/92baab69a6bf9bc7043af0bfca9fb964a1d45546.1456719558.git.jpoimboe@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 442f04c3

Makefile

+4 −1
Original line number Diff line number Diff line
@@ -993,7 +993,10 @@ prepare0: archprepare FORCE 
	$(Q)$(MAKE) $(build)=.



# All the preparing..

prepare: prepare0

prepare: prepare0 prepare-objtool



PHONY += prepare-objtool

prepare-objtool: $(if $(CONFIG_STACK_VALIDATION), tools/objtool FORCE)



# Generate some files

# ---------------------------------------------------------------------------

arch/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -583,6 +583,12 @@ config HAVE_COPY_THREAD_TLS 
	  normal C parameter passing, rather than extracting the syscall

	  argument from pt_regs.



config HAVE_STACK_VALIDATION

	bool

	help

	  Architecture supports the 'objtool check' host tool command, which

	  performs compile-time stack metadata validation.



#

# ABI hall of shame

#

lib/Kconfig.debug

+12 −0
Original line number Diff line number Diff line
@@ -342,6 +342,18 @@ config FRAME_POINTER 
	  larger and slower, but it gives very useful debugging information

	  in case of kernel bugs. (precise oopses/stacktraces/warnings)



config STACK_VALIDATION

	bool "Compile-time stack metadata validation"

	depends on HAVE_STACK_VALIDATION

	default n

	help

	  Add compile-time checks to validate stack metadata, including frame

	  pointers (if CONFIG_FRAME_POINTER is enabled).  This helps ensure

	  that runtime stack traces are more reliable.



	  For more information, see

	  tools/objtool/Documentation/stack-validation.txt.



config DEBUG_FORCE_WEAK_PER_CPU

	bool "Force weak per-cpu definitions"

	depends on DEBUG_KERNEL

scripts/Makefile.build

+35 −4
Original line number Diff line number Diff line
@@ -241,10 +241,32 @@ cmd_record_mcount = \ 
	fi;

endif



ifdef CONFIG_STACK_VALIDATION



__objtool_obj := $(objtree)/tools/objtool/objtool



objtool_args = check

ifndef CONFIG_FRAME_POINTER

objtool_args += --no-fp

endif



# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory

# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file

# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file

cmd_objtool = $(if $(patsubst y%,, \

	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \

	$(__objtool_obj) $(objtool_args) "$(@)";)

objtool_obj = $(if $(patsubst y%,, \

	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \

	$(__objtool_obj))



endif # CONFIG_STACK_VALIDATION



define rule_cc_o_c

	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \

	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \

	$(cmd_modversions)						  \

	$(cmd_objtool)						  \

	$(call echo-cmd,record_mcount)					  \

	$(cmd_record_mcount)						  \

	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
@@ -253,14 +275,23 @@ define rule_cc_o_c 
	mv -f $(dot-target).tmp $(dot-target).cmd

endef



define rule_as_o_S

	$(call echo-cmd,as_o_S) $(cmd_as_o_S);				  \

	$(cmd_objtool)						  \

	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,as_o_S)' >    \

	                                              $(dot-target).tmp;  \

	rm -f $(depfile);						  \

	mv -f $(dot-target).tmp $(dot-target).cmd

endef



# Built-in and composite module parts

$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE

$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE

	$(call cmd,force_checksrc)

	$(call if_changed_rule,cc_o_c)



# Single-part modules are special since we need to mark them in $(MODVERDIR)



$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE

$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE

	$(call cmd,force_checksrc)

	$(call if_changed_rule,cc_o_c)

	@{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)
@@ -290,8 +321,8 @@ $(obj)/%.s: $(src)/%.S FORCE 
quiet_cmd_as_o_S = AS $(quiet_modtag)  $@

cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<



$(obj)/%.o: $(src)/%.S FORCE

	$(call if_changed_dep,as_o_S)

$(obj)/%.o: $(src)/%.S $(objtool_obj) FORCE

	$(call if_changed_rule,as_o_S)



targets += $(real-objs-y) $(real-objs-m) $(lib-y)

targets += $(extra-y) $(MAKECMDGOALS) $(always)