Makefile: support flag -fsanitizer-coverage=trace-cmp

The flag enables Clang instrumentation of comparison operations
(currently not supported by GCC).  This instrumentation is needed by the
new KCOV device to collect comparison operands.

Link: http://lkml.kernel.org/r/20171011095459.70721-2-glider@google.com
Signed-off-by: Victor Chibotaru <tchibo@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: <syzkaller@googlegroups.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Victor Chibotaru 2017-11-17 15:30:50 -08:00 committed by Linus Torvalds
parent ded97d2c2b
commit d677a4d601
3 changed files with 18 additions and 2 deletions

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@ -375,8 +375,6 @@ CFLAGS_KERNEL =
AFLAGS_KERNEL =
LDFLAGS_vmlinux =
CFLAGS_GCOV := -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,)
CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,)
# Use USERINCLUDE when you must reference the UAPI directories only.
USERINCLUDE := \
@ -659,6 +657,7 @@ ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLA
KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
endif
include scripts/Makefile.kcov
include scripts/Makefile.gcc-plugins
ifdef CONFIG_READABLE_ASM

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@ -756,6 +756,16 @@ config KCOV
For more details, see Documentation/dev-tools/kcov.rst.
config KCOV_ENABLE_COMPARISONS
bool "Enable comparison operands collection by KCOV"
depends on KCOV
default n
help
KCOV also exposes operands of every comparison in the instrumented
code along with operand sizes and PCs of the comparison instructions.
These operands can be used by fuzzing engines to improve the quality
of fuzzing coverage.
config KCOV_INSTRUMENT_ALL
bool "Instrument all code by default"
depends on KCOV

7
scripts/Makefile.kcov Normal file
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@ -0,0 +1,7 @@
ifdef CONFIG_KCOV
CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,)
ifeq ($(CONFIG_KCOV_ENABLE_COMPARISONS),y)
CFLAGS_KCOV += $(call cc-option,-fsanitize-coverage=trace-cmp,)
endif
endif