[patch 02/12] kasan: fix hwasan build for gcc

Andrew Morton
2021-04-16T22:46:00Z

From: Arnd Bergmann <arnd@arndb.de>
Subject: kasan: fix hwasan build for gcc

gcc-11 adds support for -fsanitize=kernel-hwaddress, so it becomes
possible to enable CONFIG_KASAN_SW_TAGS.

Unfortunately this fails to build at the moment, because the corresponding
command line arguments use llvm specific syntax.

Change it to use the cc-param macro instead, which works on both clang and
gcc.

[elver@google.com: fixup for "kasan: fix hwasan build for gcc"]
Link: https://lkml.kernel.org/r/YHQZVfVVLE/LDK2v@elver.google.com
Link: https://lkml.kernel.org/r/20210323124112.1229772-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

scripts/Makefile.kasan | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/scripts/Makefile.kasan~kasan-fix-hwasan-build-for-gcc
+++ a/scripts/Makefile.kasan
@@ -2,6 +2,8 @@
CFLAGS_KASAN_NOSANITIZE := -fno-builtin
KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)

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

ifdef CONFIG_KASAN_INLINE
@@ -12,8 +14,6 @@ endif

CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address

-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), \
@@ -36,14 +36,14 @@ endif # CONFIG_KASAN_GENERIC
ifdef CONFIG_KASAN_SW_TAGS

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

CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
- -mllvm -hwasan-instrument-stack=$(CONFIG_KASAN_STACK) \
- -mllvm -hwasan-use-short-granules=0 \
+ $(call cc-param,hwasan-instrument-stack=$(CONFIG_KASAN_STACK)) \
+ $(call cc-param,hwasan-use-short-granules=0) \
$(instrumentation_flags)

endif # CONFIG_KASAN_SW_TAGS
_