locking/atomic: Correct (cmp)xchg() instrumentation

[linux-block.git] / scripts / Makefile.kcsan

# SPDX-License-Identifier: GPL-2.0
# GCC and Clang accept backend options differently. Do not wrap in cc-option,
# because Clang accepts "--param" even if it is unused.
ifdef CONFIG_CC_IS_CLANG
cc-param = -mllvm -$(1)
else
cc-param = --param $(1)
endif

# Keep most options here optional, to allow enabling more compilers if absence
# of some options does not break KCSAN nor causes false positive reports.
kcsan-cflags := -fsanitize=thread -fno-optimize-sibling-calls \
	$(call cc-option,$(call cc-param,tsan-compound-read-before-write=1),$(call cc-option,$(call cc-param,tsan-instrument-read-before-write=1))) \
	$(call cc-param,tsan-distinguish-volatile=1)

ifdef CONFIG_CC_IS_GCC
# GCC started warning about operations unsupported by the TSan runtime. But
# KCSAN != TSan, so just ignore these warnings.
kcsan-cflags += -Wno-tsan
endif

ifndef CONFIG_KCSAN_WEAK_MEMORY
kcsan-cflags += $(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0))
endif

export CFLAGS_KCSAN := $(kcsan-cflags)