From 5d45950dfbb1540bba3e3762a3497de8b4a715d3 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 29 May 2022 00:47:03 +0900 Subject: kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o This is a preparation for moving the objtool rule in the next commit. Signed-off-by: Masahiro Yamada Tested-by: Sedat Dilek # LLVM-14 (x86-64) --- scripts/Makefile.vmlinux_o | 61 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 scripts/Makefile.vmlinux_o (limited to 'scripts/Makefile.vmlinux_o') diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o new file mode 100644 index 000000000000..a9b375ca86d5 --- /dev/null +++ b/scripts/Makefile.vmlinux_o @@ -0,0 +1,61 @@ +# SPDX-License-Identifier: GPL-2.0-only + +PHONY := __default +__default: vmlinux.o + +include include/config/auto.conf +include $(srctree)/scripts/Kbuild.include + +# Generate a linker script to ensure correct ordering of initcalls for Clang LTO +# --------------------------------------------------------------------------- + +quiet_cmd_gen_initcalls_lds = GEN $@ + cmd_gen_initcalls_lds = \ + $(PYTHON3) $(srctree)/scripts/jobserver-exec \ + $(PERL) $(real-prereqs) > $@ + +.tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \ + $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE + $(call if_changed,gen_initcalls_lds) + +targets := .tmp_initcalls.lds + +ifdef CONFIG_LTO_CLANG +initcalls-lds := .tmp_initcalls.lds +endif + +# Link of vmlinux.o used for section mismatch analysis +# --------------------------------------------------------------------------- + +quiet_cmd_ld_vmlinux.o = LD $@ + cmd_ld_vmlinux.o = \ + $(LD) ${KBUILD_LDFLAGS} -r -o $@ \ + $(addprefix -T , $(initcalls-lds)) \ + --whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \ + --start-group $(KBUILD_VMLINUX_LIBS) --end-group \ + +define rule_ld_vmlinux.o + $(call cmd_and_savecmd,ld_vmlinux.o) +endef + +vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE + $(call if_changed_rule,ld_vmlinux.o) + +targets += vmlinux.o + +# Add FORCE to the prequisites of a target to force it to be always rebuilt. +# --------------------------------------------------------------------------- + +PHONY += FORCE +FORCE: + +# Read all saved command lines and dependencies for the $(targets) we +# may be building above, using $(if_changed{,_dep}). As an +# optimization, we don't need to read them if the target does not +# exist, we will rebuild anyway in that case. + +existing-targets := $(wildcard $(sort $(targets))) + +-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) + +.PHONY: $(PHONY) -- cgit v1.2.3 From b42d2306502419688190aa6dd4dab4a6def24b3d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 29 May 2022 00:47:04 +0900 Subject: kbuild: factor out the common objtool arguments scripts/Makefile.build and scripts/link-vmlinux.sh have similar setups for the objtool arguments. It was difficult to factor out them because all the vmlinux build rules were written in a shell script. It is somewhat tedious to touch the two files every time a new objtool option is supported. To reduce the code duplication, move the objtool for vmlinux.o into scripts/Makefile.vmlinux_o. Then, move the common macros to Makefile.lib so they are shared between Makefile.build and Makefile.vmlinux_o. Signed-off-by: Masahiro Yamada Tested-by: Sedat Dilek # LLVM-14 (x86-64) --- scripts/Makefile.vmlinux_o | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'scripts/Makefile.vmlinux_o') diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o index a9b375ca86d5..3c97a1564947 100644 --- a/scripts/Makefile.vmlinux_o +++ b/scripts/Makefile.vmlinux_o @@ -6,6 +6,9 @@ __default: vmlinux.o include include/config/auto.conf include $(srctree)/scripts/Kbuild.include +# for objtool +include $(srctree)/scripts/Makefile.lib + # Generate a linker script to ensure correct ordering of initcalls for Clang LTO # --------------------------------------------------------------------------- @@ -24,6 +27,27 @@ ifdef CONFIG_LTO_CLANG initcalls-lds := .tmp_initcalls.lds endif +# objtool for vmlinux.o +# --------------------------------------------------------------------------- +# +# For LTO and IBT, objtool doesn't run on individual translation units. +# Run everything on vmlinux instead. + +objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION)) + +# Reuse objtool_args defined in scripts/Makefile.lib if LTO or IBT is enabled. +# +# Add some more flags as needed. +# --no-unreachable and --link might be added twice, but it is fine. +# +# Expand objtool_args to a simple variable to avoid circular reference. + +objtool_args := \ + $(if $(delay-objtool),$(objtool_args)) \ + $(if $(CONFIG_NOINSTR_VALIDATION), --noinstr) \ + $(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \ + --link + # Link of vmlinux.o used for section mismatch analysis # --------------------------------------------------------------------------- @@ -33,9 +57,11 @@ quiet_cmd_ld_vmlinux.o = LD $@ $(addprefix -T , $(initcalls-lds)) \ --whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \ --start-group $(KBUILD_VMLINUX_LIBS) --end-group \ + $(cmd_objtool) define rule_ld_vmlinux.o $(call cmd_and_savecmd,ld_vmlinux.o) + $(call cmd,gen_objtooldep) endef vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE -- cgit v1.2.3