kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles

Move CFLAGS_KASAN*, CFLAGS_UBSAN, CFLAGS_KCSAN to Makefile.kasan,
Makefile.ubsan, Makefile.kcsan, respectively.

This commit also avoids the same -fsanitize=* flags being added to
CFLAGS_UBSAN multiple times.

Prior to this commit, the ubsan flags were appended by the '+='
operator, without any initialization. Some build targets such as
'make bindeb-pkg' recurses to the top Makefile, and ended up with
adding the same flags to CFLAGS_UBSAN twice.

Clear CFLAGS_UBSAN with ':=' to make it a simply expanded variable.
This is better than a recursively expanded variable, which evaluates
$(call cc-option, ...) multiple times before Kbuild starts descending
to subdirectories.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Marco Elver <elver@google.com>

diff --git a/Makefile b/Makefile
index 744b6c6..06890bb 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -516,7 +516,6 @@ export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
-export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN CFLAGS_KCSAN
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 1532f1a..1e000cc 100644 (file)
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -47,3 +47,5 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
                $(instrumentation_flags)
 
 endif # CONFIG_KASAN_SW_TAGS
+
+export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE

diff --git a/scripts/Makefile.kcsan b/scripts/Makefile.kcsan
index c50f27b..cec50d7 100644 (file)
--- a/scripts/Makefile.kcsan
+++ b/scripts/Makefile.kcsan
@@ -9,7 +9,7 @@ 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.
-CFLAGS_KCSAN := -fsanitize=thread \
+export CFLAGS_KCSAN := -fsanitize=thread \
        $(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0) -fno-optimize-sibling-calls) \
        $(call cc-option,$(call cc-param,tsan-instrument-read-before-write=1)) \
        $(call cc-param,tsan-distinguish-volatile=1)

diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
index 2734802..c661484 100644 (file)
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -1,4 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
+
+export CFLAGS_UBSAN :=
+
 ifdef CONFIG_UBSAN_ALIGNMENT
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment)
 endif