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. $(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested by Nathan Chancellor [1]. [1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/ Signed-off-by: Masahiro Yamada Tested-by: Nick Desaulniers Reviewed-by: Nicolas Schier --- Documentation/kbuild/makefiles.rst | 18 +----------------- 1 file changed, 1 insertion(+), 17 deletions(-) (limited to 'Documentation/kbuild/makefiles.rst') diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst index ee7e3ea1fbe1..5a6a8426cc97 100644 --- a/Documentation/kbuild/makefiles.rst +++ b/Documentation/kbuild/makefiles.rst @@ -340,19 +340,7 @@ more details, with real examples. Examples are: - 1) head objects - - Some objects must be placed at the head of vmlinux. They are - directly linked to vmlinux without going through built-in.a - A typical use-case is an object that contains the entry point. - - arch/$(SRCARCH)/Makefile should specify such objects as head-y. - - Discussion: - Given that we can control the section order in the linker script, - why do we need head-y? - - 2) vmlinux linker script + 1) vmlinux linker script The linker script for vmlinux is located at arch/$(SRCARCH)/kernel/vmlinux.lds @@ -360,10 +348,6 @@ more details, with real examples. Example:: # arch/x86/kernel/Makefile - extra-y := head_$(BITS).o - extra-y += head$(BITS).o - extra-y += ebda.o - extra-y += platform-quirks.o extra-y += vmlinux.lds $(extra-y) should only contain targets needed for vmlinux. -- cgit v1.2.3