[PATCH 1/2] kbuild: change tool coverage variables to take the path relative to $(obj)

From: Masahiro Yamada
Date: Sat Feb 17 2024 - 00:55:23 EST


Commit 54b8ae66ae1a ("kbuild: change *FLAGS_<basetarget>.o to take the
path relative to $(obj)") changed the syntax of per-file compiler flags.

The situation is the same for the following variables:

OBJECT_FILES_NON_STANDARD_<basetarget>.o
GCOV_PROFILE_<basetarget>.o
KASAN_SANITIZE_<basetarget>.o
KMSAN_SANITIZE_<basetarget>.o
KMSAN_ENABLE_CHECKS_<basetarget>.o
UBSAN_SANITIZE_<basetarget>.o
KCOV_INSTRUMENT_<basetarget>.o
KCSAN_SANITIZE_<basetarget>.o
KCSAN_INSTRUMENT_BARRIERS_<basetarget>.o

The <basetarget> is the filename of the target with its directory and
suffix stripped.

This syntax comes into a trouble when two files with the same basename
appear in one Makefile, for example:

obj-y += dir1/foo.o
obj-y += dir2/foo.o
OBJECT_FILES_NON_STANDARD_foo.o := y

OBJECT_FILES_NON_STANDARD_foo.o is applied to both dir1/foo.o and
dir2/foo.o. This syntax is not flexbile enough to handle cases where
one of them is a standard object, but the other is not.

It is more sensible to use the relative path to the Makefile, like this:

obj-y += dir1/foo.o
OBJECT_FILES_NON_STANDARD_dir1/foo.o := y
obj-y += dir2/foo.o
OBJECT_FILES_NON_STANDARD_dir2/foo.o := y

To maintain the current behavior, I made adjustments to two Makefiles:

- arch/x86/entry/vdso/Makefile, which compiles vclock_gettime.o and
vdso32/vclock_gettime.o

- arch/x86/kvm/Makefile, which compiles vmx/vmenter.o and svm/vmenter.o

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

arch/x86/entry/vdso/Makefile | 2 ++
arch/x86/kvm/Makefile | 3 ++-
scripts/Makefile.build | 2 +-
scripts/Makefile.lib | 16 ++++++++--------
4 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 7a97b17f28b7..148adfdb2325 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -9,7 +9,9 @@ include $(srctree)/lib/vdso/Makefile
# Sanitizer runtimes are unavailable and cannot be linked here.
KASAN_SANITIZE := n
KMSAN_SANITIZE_vclock_gettime.o := n
+KMSAN_SANITIZE_vdso32/vclock_gettime.o := n
KMSAN_SANITIZE_vgetcpu.o := n
+KMSAN_SANITIZE_vdso32/vgetcpu.o := n

UBSAN_SANITIZE := n
KCSAN_SANITIZE := n
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 475b5fa917a6..a88bb14266b6 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -4,7 +4,8 @@ ccflags-y += -I $(srctree)/arch/x86/kvm
ccflags-$(CONFIG_KVM_WERROR) += -Werror

ifeq ($(CONFIG_FRAME_POINTER),y)
-OBJECT_FILES_NON_STANDARD_vmenter.o := y
+OBJECT_FILES_NON_STANDARD_vmx/vmenter.o := y
+OBJECT_FILES_NON_STANDARD_svm/vmenter.o := y
endif

include $(srctree)/virt/kvm/Makefile.kvm
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 4971f54c855e..256db2a0e984 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -214,7 +214,7 @@ endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file

-is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)
+is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),y)

$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index b35d39022a30..328c0d77ed48 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -154,7 +154,7 @@ _cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds)
#
ifeq ($(CONFIG_GCOV_KERNEL),y)
_c_flags += $(if $(patsubst n%,, \
- $(GCOV_PROFILE_$(basetarget).o)$(GCOV_PROFILE)$(CONFIG_GCOV_PROFILE_ALL)), \
+ $(GCOV_PROFILE_$(target-stem).o)$(GCOV_PROFILE)$(CONFIG_GCOV_PROFILE_ALL)), \
$(CFLAGS_GCOV))
endif

@@ -165,29 +165,29 @@ endif
ifeq ($(CONFIG_KASAN),y)
ifneq ($(CONFIG_KASAN_HW_TAGS),y)
_c_flags += $(if $(patsubst n%,, \
- $(KASAN_SANITIZE_$(basetarget).o)$(KASAN_SANITIZE)y), \
+ $(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)y), \
$(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
endif
endif

ifeq ($(CONFIG_KMSAN),y)
_c_flags += $(if $(patsubst n%,, \
- $(KMSAN_SANITIZE_$(basetarget).o)$(KMSAN_SANITIZE)y), \
+ $(KMSAN_SANITIZE_$(target-stem).o)$(KMSAN_SANITIZE)y), \
$(CFLAGS_KMSAN))
_c_flags += $(if $(patsubst n%,, \
- $(KMSAN_ENABLE_CHECKS_$(basetarget).o)$(KMSAN_ENABLE_CHECKS)y), \
+ $(KMSAN_ENABLE_CHECKS_$(target-stem).o)$(KMSAN_ENABLE_CHECKS)y), \
, -mllvm -msan-disable-checks=1)
endif

ifeq ($(CONFIG_UBSAN),y)
_c_flags += $(if $(patsubst n%,, \
- $(UBSAN_SANITIZE_$(basetarget).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZE_ALL)), \
+ $(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZE_ALL)), \
$(CFLAGS_UBSAN))
endif

ifeq ($(CONFIG_KCOV),y)
_c_flags += $(if $(patsubst n%,, \
- $(KCOV_INSTRUMENT_$(basetarget).o)$(KCOV_INSTRUMENT)$(CONFIG_KCOV_INSTRUMENT_ALL)), \
+ $(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(CONFIG_KCOV_INSTRUMENT_ALL)), \
$(CFLAGS_KCOV))
endif

@@ -197,12 +197,12 @@ endif
#
ifeq ($(CONFIG_KCSAN),y)
_c_flags += $(if $(patsubst n%,, \
- $(KCSAN_SANITIZE_$(basetarget).o)$(KCSAN_SANITIZE)y), \
+ $(KCSAN_SANITIZE_$(target-stem).o)$(KCSAN_SANITIZE)y), \
$(CFLAGS_KCSAN))
# Some uninstrumented files provide implied barriers required to avoid false
# positives: set KCSAN_INSTRUMENT_BARRIERS for barrier instrumentation only.
_c_flags += $(if $(patsubst n%,, \
- $(KCSAN_INSTRUMENT_BARRIERS_$(basetarget).o)$(KCSAN_INSTRUMENT_BARRIERS)n), \
+ $(KCSAN_INSTRUMENT_BARRIERS_$(target-stem).o)$(KCSAN_INSTRUMENT_BARRIERS)n), \
-D__KCSAN_INSTRUMENT_BARRIERS__)
endif

--
2.40.1