Re: [PATCH v2 4/5] kasan: support LLVM-style asan parameters

[Dmitry Vyukov]

On Wed, Nov 29, 2017 at 10:50 PM, 'Paul Lawrence' via kasan-dev
<kasan-dev@xxxxxxxxxxxxxxxx> wrote:
> Use cc-option to figure out whether the compiler's sanitizer uses
> LLVM-style parameters ("-mllvm -asan-foo=bar") or GCC-style parameters
> ("--param asan-foo=bar").
>
> Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx>
> Signed-off-by: Paul Lawrence <paullawrence@xxxxxxxxxx>
>
> ---
>  scripts/Makefile.kasan | 39 +++++++++++++++++++++++++++------------
>  1 file changed, 27 insertions(+), 12 deletions(-)
>
> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> index 1ce7115aa499..89c5b166adec 100644
> --- a/scripts/Makefile.kasan
> +++ b/scripts/Makefile.kasan
> @@ -10,24 +10,39 @@ KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
>
>  CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
>
> -CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
> -               -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET) \
> -               --param asan-stack=1 --param asan-globals=1 \
> -               --param asan-instrumentation-with-call-threshold=$(call_threshold))
> -
>  ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
>     ifneq ($(CONFIG_COMPILE_TEST),y)
>          $(warning Cannot use CONFIG_KASAN: \
>              -fsanitize=kernel-address is not supported by compiler)
>     endif
>  else
> -    ifeq ($(CFLAGS_KASAN),)
> -        ifneq ($(CONFIG_COMPILE_TEST),y)
> -            $(warning CONFIG_KASAN: compiler does not support all options.\
> -                Trying minimal configuration)
> -        endif
> -        CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
> -    endif
> +   # -fasan-shadow-offset fails without -fsanitize
> +   CFLAGS_KASAN_SHADOW := \
> +               $(call cc-option, -fsanitize=kernel-address \
> +                       -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET))
> +   ifeq ($(CFLAGS_KASAN_SHADOW),)
> +      CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
> +   else
> +      CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW)
> +   endif
> +
> +   # Now add all the compiler specific options that are valid standalone
> +   CFLAGS_KASAN := $(CFLAGS_KASAN) \
> +       $(call cc-option, --param asan-globals=1) \
> +       $(call cc-option, --param asan-instrument-allocas=1) \
> +       $(call cc-option, --param asan-instrumentation-with-call-threshold=$(call_threshold)) \
> +       $(call cc-option, -mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)) \
> +       $(call cc-option, -mllvm -asan-stack=1) \
> +       $(call cc-option, -mllvm -asan-globals=1) \
> +       $(call cc-option, -mllvm -asan-use-after-scope=1) \
> +       $(call cc-option, -mllvm -asan-instrumentation-with-call-threshold=$(call_threshold))
> +
> +
> +   # This option crashes on gcc 4.9, and is not available on clang
> +   ifeq ($(call cc-ifversion, -ge, 0500, y), y)
> +        CFLAGS_KASAN := $(CFLAGS_KASAN) $(call cc-option, --param asan-stack=1)
> +   endif
> +
>  endif
>
>  CFLAGS_KASAN += $(call cc-option, -fsanitize-address-use-after-scope)


Acked-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>