| 1 | # SPDX-License-Identifier: GPL-2.0-only |
| 2 | |
| 3 | PHONY := __default |
| 4 | __default: vmlinux.o |
| 5 | |
| 6 | include include/config/auto.conf |
| 7 | include $(srctree)/scripts/Kbuild.include |
| 8 | |
| 9 | # for objtool |
| 10 | include $(srctree)/scripts/Makefile.lib |
| 11 | |
| 12 | # Generate a linker script to ensure correct ordering of initcalls for Clang LTO |
| 13 | # --------------------------------------------------------------------------- |
| 14 | |
| 15 | quiet_cmd_gen_initcalls_lds = GEN $@ |
| 16 | cmd_gen_initcalls_lds = \ |
| 17 | $(PYTHON3) $(srctree)/scripts/jobserver-exec \ |
| 18 | $(PERL) $(real-prereqs) > $@ |
| 19 | |
| 20 | .tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \ |
| 21 | $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE |
| 22 | $(call if_changed,gen_initcalls_lds) |
| 23 | |
| 24 | targets := .tmp_initcalls.lds |
| 25 | |
| 26 | ifdef CONFIG_LTO_CLANG |
| 27 | initcalls-lds := .tmp_initcalls.lds |
| 28 | endif |
| 29 | |
| 30 | # objtool for vmlinux.o |
| 31 | # --------------------------------------------------------------------------- |
| 32 | # |
| 33 | # For LTO and IBT, objtool doesn't run on individual translation units. |
| 34 | # Run everything on vmlinux instead. |
| 35 | |
| 36 | objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION)) |
| 37 | |
| 38 | # Reuse objtool_args defined in scripts/Makefile.lib if LTO or IBT is enabled. |
| 39 | # |
| 40 | # Add some more flags as needed. |
| 41 | # --no-unreachable and --link might be added twice, but it is fine. |
| 42 | # |
| 43 | # Expand objtool_args to a simple variable to avoid circular reference. |
| 44 | |
| 45 | objtool_args := \ |
| 46 | $(if $(delay-objtool),$(objtool_args)) \ |
| 47 | $(if $(CONFIG_NOINSTR_VALIDATION), --noinstr) \ |
| 48 | $(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \ |
| 49 | --link |
| 50 | |
| 51 | # Link of vmlinux.o used for section mismatch analysis |
| 52 | # --------------------------------------------------------------------------- |
| 53 | |
| 54 | quiet_cmd_ld_vmlinux.o = LD $@ |
| 55 | cmd_ld_vmlinux.o = \ |
| 56 | $(LD) ${KBUILD_LDFLAGS} -r -o $@ \ |
| 57 | $(addprefix -T , $(initcalls-lds)) \ |
| 58 | --whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \ |
| 59 | --start-group $(KBUILD_VMLINUX_LIBS) --end-group \ |
| 60 | $(cmd_objtool) |
| 61 | |
| 62 | define rule_ld_vmlinux.o |
| 63 | $(call cmd_and_savecmd,ld_vmlinux.o) |
| 64 | $(call cmd,gen_objtooldep) |
| 65 | endef |
| 66 | |
| 67 | vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE |
| 68 | $(call if_changed_rule,ld_vmlinux.o) |
| 69 | |
| 70 | targets += vmlinux.o |
| 71 | |
| 72 | # Add FORCE to the prequisites of a target to force it to be always rebuilt. |
| 73 | # --------------------------------------------------------------------------- |
| 74 | |
| 75 | PHONY += FORCE |
| 76 | FORCE: |
| 77 | |
| 78 | # Read all saved command lines and dependencies for the $(targets) we |
| 79 | # may be building above, using $(if_changed{,_dep}). As an |
| 80 | # optimization, we don't need to read them if the target does not |
| 81 | # exist, we will rebuild anyway in that case. |
| 82 | |
| 83 | existing-targets := $(wildcard $(sort $(targets))) |
| 84 | |
| 85 | -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) |
| 86 | |
| 87 | .PHONY: $(PHONY) |