From 3216484550610470013b7ce1c9ed272da0a74589 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 25 Sep 2022 03:19:14 +0900 Subject: kbuild: use obj-y instead extra-y for objects placed at the head The objects placed at the head of vmlinux need special treatments: - arch/$(SRCARCH)/Makefile adds them to head-y in order to place them before other archives in the linker command line. - arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of obj-y to avoid them going into built-in.a. This commit gets rid of the latter. Create vmlinux.a to collect all the objects that are unconditionally linked to vmlinux. The objects listed in head-y are moved to the head of vmlinux.a by using 'ar m'. With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y for builtin objects. There is no *.o that is directly linked to vmlinux. Drop unneeded code in scripts/clang-tools/gen_compile_commands.py. $(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested by Nathan Chancellor [1]. [1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/ Signed-off-by: Masahiro Yamada Tested-by: Nick Desaulniers Reviewed-by: Nicolas Schier --- arch/arm/kernel/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 553866751e1a..8feaa3217ec5 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -89,7 +89,7 @@ obj-$(CONFIG_VDSO) += vdso.o obj-$(CONFIG_EFI) += efi.o obj-$(CONFIG_PARAVIRT) += paravirt.o -head-y := head$(MMUEXT).o +obj-y += head$(MMUEXT).o obj-$(CONFIG_DEBUG_LL) += debug.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o obj-$(CONFIG_ARM_PATCH_PHYS_VIRT) += phys2virt.o @@ -109,4 +109,4 @@ obj-$(CONFIG_HAVE_ARM_SMCCC) += smccc-call.o obj-$(CONFIG_GENERIC_CPU_VULNERABILITIES) += spectre.o -extra-y := $(head-y) vmlinux.lds +extra-y := vmlinux.lds -- cgit v1.2.3 From ce697ccee1a8661da4e23fbe5f3d45d8d6922c20 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 25 Sep 2022 03:19:15 +0900 Subject: kbuild: remove head-y syntax Kbuild puts the objects listed in head-y at the head of vmlinux. Conventionally, we do this for head*.S, which contains the kernel entry point. A counter approach is to control the section order by the linker script. Actually, the code marked as __HEAD goes into the ".head.text" section, which is placed before the normal ".text" section. I do not know if both of them are needed. From the build system perspective, head-y is not mandatory. If you can achieve the proper code placement by the linker script only, it would be cleaner. I collected the current head-y objects into head-object-list.txt. It is a whitelist. My hope is it will be reduced in the long run. Signed-off-by: Masahiro Yamada Tested-by: Nick Desaulniers Reviewed-by: Nicolas Schier --- arch/arm/Makefile | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/Makefile b/arch/arm/Makefile index 56f655deebb1..29d15c9a433e 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -134,9 +134,6 @@ KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/uni CHECKFLAGS += -D__arm__ -#Default value -head-y := arch/arm/kernel/head$(MMUEXT).o - # Text offset. This list is sorted numerically by address in order to # provide a means to avoid/resolve conflicts in multi-arch kernels. # Note: the 32kB below this value is reserved for use by the kernel -- cgit v1.2.3