kasan: fix hwasan build for gcc

[ Upstream commit 5c595ac ]

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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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