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authorMasahiro Yamada <masahiroy@kernel.org>2020-07-02 04:29:36 +0900
committerMasahiro Yamada <masahiroy@kernel.org>2020-08-10 01:32:58 +0900
commit3ec8a5b33deacdeca4bef24fb15498a975e875ba (patch)
tree8e358066d252e9021b3c587d5562f20edc2847e4
parentcc8a51ca6f05ade72f7dd2624bc5f9b948e216fc (diff)
kbuild: do not export LDFLAGS_vmlinux
When you clean the build tree for ARCH=arm, you may see the following error message from 'nm' command: $ make -j24 ARCH=arm clean CLEAN arch/arm/crypto CLEAN arch/arm/kernel CLEAN arch/arm/mach-at91 CLEAN arch/arm/mach-omap2 CLEAN arch/arm/vdso CLEAN certs CLEAN lib CLEAN usr CLEAN net/wireless CLEAN drivers/firmware/efi/libstub nm: 'arch/arm/boot/compressed/../../../../vmlinux': No such file /bin/sh: 1: arithmetic expression: expecting primary: " " CLEAN arch/arm/boot/compressed CLEAN drivers/scsi CLEAN drivers/tty/vt CLEAN arch/arm/boot CLEAN vmlinux.symvers modules.builtin modules.builtin.modinfo Even if you rerun the same command, the error message will not be shown despite vmlinux is already gone. To reproduce it, the parallel option -j is needed. Single thread cleaning always executes 'archclean', 'vmlinuxclean' in this order, so vmlinux still exists when arch/arm/boot/compressed/ is cleaned. Looking at arch/arm/boot/compressed/Makefile does not help understand the reason of the error message. Both KBSS_SZ and LDFLAGS_vmlinux are assigned with '=' operator, hence, they are not expanded unless used. Obviously, 'make clean' does not use them. In fact, the root cause exists in the top Makefile: export LDFLAGS_vmlinux Since LDFLAGS_vmlinux is an exported variable, LDFLAGS_vmlinux in arch/arm/boot/compressed/Makefile is expanded when scripts/Makefile.clean has a command to execute. This is why the error message shows up only when there exist build artifacts in arch/arm/boot/compressed/. Adding 'unexport LDFLAGS_vmlinux' to arch/arm/boot/compressed/Makefile will fix it as far as ARCH=arm is concerned, but I think the proper fix is to get rid of 'export LDFLAGS_vmlinux' from the top Makefile. LDFLAGS_vmlinux in the top Makefile contains linker flags for the top vmlinux. LDFLAGS_vmlinux in arch/arm/boot/compressed/Makefile is for arch/arm/boot/compressed/vmlinux. They just happen to have the same variable name, but are used for different purposes. Stop shadowing LDFLAGS_vmlinux. This commit passes LDFLAGS_vmlinux to scripts/link-vmlinux.sh via a command line parameter instead of via an environment variable. LD and KBUILD_LDFLAGS are exported, but I did the same for consistency. Anyway, they must be included in cmd_link-vmlinux to allow if_changed to detect the changes in LD or KBUILD_LDFLAGS. The following Makefiles are not affected: arch/arm/boot/compressed/Makefile arch/h8300/boot/compressed/Makefile arch/nios2/boot/compressed/Makefile arch/parisc/boot/compressed/Makefile arch/s390/boot/compressed/Makefile arch/sh/boot/compressed/Makefile arch/sh/boot/romimage/Makefile arch/x86/boot/compressed/Makefile They use ':=' or '=' to clear the LDFLAGS_vmlinux inherited from the top Makefile. We need to take a closer look at the impact to unicore32 and xtensa. arch/unicore32/boot/compressed/Makefile only uses '+=' operator for LDFLAGS_vmlinux. So, the decompressor previously inherited the linker flags from the top Makefile. However, commit 70fac51feaf2 ("unicore32 additional architecture files: boot process") was merged before commit 1f2bfbd00e46 ("kbuild: link of vmlinux moved to a script"). So, I rather consider this is a bug fix of 1f2bfbd00e46. arch/xtensa/boot/boot-elf/Makefile is also affected, but this is also considered a fix for the same reason. It did not inherit LDFLAGS_vmlinux when commit 4bedea945451 ("[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 2") was merged. I deleted $(LDFLAGS_vmlinux), which is now empty. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
-rw-r--r--Makefile3
-rw-r--r--arch/xtensa/boot/boot-elf/Makefile2
-rwxr-xr-xscripts/link-vmlinux.sh4
3 files changed, 6 insertions, 3 deletions
diff --git a/Makefile b/Makefile
index ea283c9bbaa8..ebf4d3ce492c 100644
--- a/Makefile
+++ b/Makefile
@@ -1100,7 +1100,6 @@ KBUILD_VMLINUX_OBJS += $(patsubst %/,%/built-in.a, $(drivers-y))
export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS
export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
-export LDFLAGS_vmlinux
# used by scripts/Makefile.package
export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) LICENSES arch include scripts tools)
@@ -1132,7 +1131,7 @@ ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
# Final link of vmlinux with optional arch pass after final link
cmd_link-vmlinux = \
- $(CONFIG_SHELL) $< $(LD) $(KBUILD_LDFLAGS) $(LDFLAGS_vmlinux) ; \
+ $(CONFIG_SHELL) $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)"; \
$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE
diff --git a/arch/xtensa/boot/boot-elf/Makefile b/arch/xtensa/boot/boot-elf/Makefile
index 12ae1e91cb75..a62a25506536 100644
--- a/arch/xtensa/boot/boot-elf/Makefile
+++ b/arch/xtensa/boot/boot-elf/Makefile
@@ -25,7 +25,7 @@ $(obj)/Image.o: vmlinux.bin $(OBJS)
$(OBJS) $@
$(obj)/../Image.elf: $(obj)/Image.o $(obj)/boot.lds
- $(Q)$(LD) $(KBUILD_LDFLAGS) $(LDFLAGS_vmlinux) \
+ $(Q)$(LD) $(KBUILD_LDFLAGS) \
-T $(obj)/boot.lds \
--build-id=none \
-o $@ $(obj)/Image.o
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 92dd745906f4..68e7de2dbe90 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -30,6 +30,10 @@
# Error out on error
set -e
+LD="$1"
+KBUILD_LDFLAGS="$2"
+LDFLAGS_vmlinux="$3"
+
# Nice output in kbuild format
# Will be supressed by "make -s"
info()