# SPDX-License-Identifier: GPL-2.0
ifdef CONFIG_KASAN_GENERIC

ifdef CONFIG_KASAN_INLINE
	call_threshold := 10000
else
	call_threshold := 0
endif

KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)

CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address

ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
    ifneq ($(CONFIG_COMPILE_TEST),y)
        $(error Cannot use CONFIG_KASAN_GENERIC: \
          -fsanitize=kernel-address is not supported by compiler)
    endif
endif

cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))

# -fasan-shadow-offset fails without -fsanitize
CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
			-fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
			$(call cc-option, -fsanitize=kernel-address \
			-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))

ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
	CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
else
	# Now add all the compiler specific options that are valid standalone
	CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
	 $(call cc-param,asan-globals=1) \
	 $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
	 $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \
	 $(call cc-param,asan-instrument-allocas=1)
endif

endif # CONFIG_KASAN_GENERIC

ifdef CONFIG_KASAN_SW_TAGS

CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-hwaddress

ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
    ifneq ($(CONFIG_COMPILE_TEST),y)
        $(error Cannot use CONFIG_KASAN_SW_TAGS: \
          -fsanitize=kernel-hwaddress is not supported by compiler)
    endif
endif

ifdef CONFIG_KASAN_INLINE
    instrumentation_flags := -mllvm -hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
else
    instrumentation_flags := -mllvm -hwasan-instrument-with-calls=1
endif

CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
		-mllvm -hwasan-instrument-stack=0 \
		$(instrumentation_flags)

endif # CONFIG_KASAN_SW_TAGS

# clang+kasan stack usage bug. Worked around with KASAN_THREAD_SHIFT.
ifneq ($(CONFIG_FRAME_WARN),0)
CFLAGS_KASAN += -Wno-error=frame-larger-than=
endif

ifdef CONFIG_KASAN
CFLAGS_KASAN_NOSANITIZE := -fno-builtin
endif