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| author | Masahiro Yamada <masahiroy@kernel.org> | 2022-09-24 21:19:14 +0300 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2022-10-02 12:04:05 +0300 |
| commit | 3216484550610470013b7ce1c9ed272da0a74589 (patch) | |
| tree | e24e7df02e90b7e798ae5aa67a5e4468142978c8 /Makefile | |
| parent | 4b0986590062ce12c134c00cf32b9f9b846aeff5 (diff) | |
| download | linux-3216484550610470013b7ce1c9ed272da0a74589.tar.xz | |
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 <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 23 |
1 files changed, 18 insertions, 5 deletions
@@ -645,6 +645,8 @@ else __all: modules endif +targets := + # Decide whether to build built-in, modular, or both. # Normally, just do built-in. @@ -1107,7 +1109,7 @@ export ARCH_LIB := $(filter %/, $(libs-y)) export ARCH_DRIVERS := $(drivers-y) $(drivers-m) # Externally visible symbols (used by link-vmlinux.sh) -KBUILD_VMLINUX_OBJS := $(head-y) ./built-in.a +KBUILD_VMLINUX_OBJS := ./built-in.a ifdef CONFIG_MODULES KBUILD_VMLINUX_OBJS += $(patsubst %/, %/lib.a, $(filter %/, $(libs-y))) KBUILD_VMLINUX_LIBS := $(filter-out %/, $(libs-y)) @@ -1115,7 +1117,7 @@ else KBUILD_VMLINUX_LIBS := $(patsubst %/,%/lib.a, $(libs-y)) endif -export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS +export KBUILD_VMLINUX_LIBS export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds # Recurse until adjust_autoksyms.sh is satisfied @@ -1140,7 +1142,18 @@ quiet_cmd_autoksyms_h = GEN $@ $(autoksyms_h): $(call cmd,autoksyms_h) -vmlinux.o: autoksyms_recursive $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE +# '$(AR) mPi' needs 'T' to workaround the bug of llvm-ar <= 14 +quiet_cmd_ar_vmlinux.a = AR $@ + cmd_ar_vmlinux.a = \ + rm -f $@; \ + $(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \ + $(AR) mPiT $$($(AR) t $@ | head -n1) $@ $(head-y) + +targets += vmlinux.a +vmlinux.a: $(KBUILD_VMLINUX_OBJS) autoksyms_recursive FORCE + $(call if_changed,ar_vmlinux.a) + +vmlinux.o: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux_o ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) @@ -1153,7 +1166,7 @@ cmd_link-vmlinux = \ vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) modpost FORCE +$(call if_changed_dep,link-vmlinux) -targets := vmlinux +targets += vmlinux # The actual objects are generated when descending, # make sure no implicit rule kicks in @@ -1878,7 +1891,7 @@ quiet_cmd_gen_compile_commands = GEN $@ cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs)) $(extmod_prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \ - $(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \ + $(if $(KBUILD_EXTMOD),, vmlinux.a $(KBUILD_VMLINUX_LIBS)) \ $(if $(CONFIG_MODULES), $(MODORDER)) FORCE $(call if_changed,gen_compile_commands) |