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objtool: Add CONFIG_STACK_VALIDATION option

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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: Josh 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Josh Poimboeuf 2016-02-28 22:22:42 -06:00 committed by Ingo Molnar
parent 442f04c34a
commit b9ab5ebb14
4 changed files with 57 additions and 5 deletions
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5
Makefile
View file

@ -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
# ---------------------------------------------------------------------------

6
arch/Kconfig
View file

@ -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
#

12
lib/Kconfig.debug
View file

@ -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

39
scripts/Makefile.build
View file

@ -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)