linux-next/scripts/Makefile.vmlinux

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# SPDX-License-Identifier: GPL-2.0-only
PHONY := __default
__default: vmlinux
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include include/config/auto.conf
include $(srctree)/scripts/Kbuild.include
include $(srctree)/scripts/Makefile.lib
targets :=
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%.o: %.c FORCE
$(call if_changed_dep,cc_o_c)
kbuild: add generic support for built-in boot DTBs Some architectures embed boot DTBs in vmlinux. A potential issue for these architectures is a race condition during parallel builds because Kbuild descends into arch/*/boot/dts/ twice. One build thread is initiated by the 'dtbs' target, which is a prerequisite of the 'all' target in the top-level Makefile: ifdef CONFIG_OF_EARLY_FLATTREE all: dtbs endif For architectures that support the built-in boot dtb, arch/*/boot/dts/ is visited also during the ordinary directory traversal in order to build obj-y objects that wrap DTBs. Since these build threads are unaware of each other, they can run simultaneously during parallel builds. This commit introduces a generic build rule to scripts/Makefile.vmlinux to support embedded boot DTBs in a race-free way. Architectures that want to use this rule need to select CONFIG_GENERIC_BUILTIN_DTB. After the migration, Makefiles under arch/*/boot/dts/ will be visited only once to build only *.dtb files. This change also aims to unify the CONFIG options used for built-in DTBs support. Currently, different architectures use different CONFIG options for the same purposes. With this commit, the CONFIG options will be unified as follows: - CONFIG_GENERIC_BUILTIN_DTB This enables the generic rule for built-in boot DTBs. This will be renamed to CONFIG_BUILTIN_DTB after all architectures migrate to the generic rule. - CONFIG_BUILTIN_DTB_NAME This specifies the path to the embedded DTB. (relative to arch/*/boot/dts/) - CONFIG_BUILTIN_DTB_ALL If this is enabled, all DTB files compiled under arch/*/boot/dts/ are embedded into vmlinux. Only used by MIPS. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-09-23 07:56:03 +00:00
%.o: %.S FORCE
$(call if_changed_dep,as_o_S)
# Built-in dtb
# ---------------------------------------------------------------------------
quiet_cmd_wrap_dtbs = WRAP $@
cmd_wrap_dtbs = { \
echo '\#include <asm-generic/vmlinux.lds.h>'; \
echo '.section .dtb.init.rodata,"a"'; \
while read dtb; do \
symbase=__dtb_$$(basename -s .dtb "$${dtb}" | tr - _); \
echo '.balign STRUCT_ALIGNMENT'; \
echo ".global $${symbase}_begin"; \
echo "$${symbase}_begin:"; \
echo '.incbin "'$$dtb'" '; \
echo ".global $${symbase}_end"; \
echo "$${symbase}_end:"; \
done < $<; \
} > $@
.builtin-dtbs.S: .builtin-dtbs-list FORCE
$(call if_changed,wrap_dtbs)
quiet_cmd_gen_dtbs_list = GEN $@
cmd_gen_dtbs_list = \
$(if $(CONFIG_BUILTIN_DTB_NAME), echo "arch/$(SRCARCH)/boot/dts/$(CONFIG_BUILTIN_DTB_NAME).dtb",:) > $@
.builtin-dtbs-list: arch/$(SRCARCH)/boot/dts/dtbs-list FORCE
$(call if_changed,$(if $(CONFIG_BUILTIN_DTB_ALL),copy,gen_dtbs_list))
targets += .builtin-dtbs-list
ifdef CONFIG_GENERIC_BUILTIN_DTB
targets += .builtin-dtbs.S .builtin-dtbs.o
vmlinux: .builtin-dtbs.o
endif
# vmlinux
# ---------------------------------------------------------------------------
ifdef CONFIG_MODULES
targets += .vmlinux.export.o
vmlinux: .vmlinux.export.o
endif
ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
# Final link of vmlinux with optional arch pass after final link
cmd_link_vmlinux = \
$< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)"; \
$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
targets += vmlinux
vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
+$(call if_changed_dep,link_vmlinux)
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kbuild: generate offset range data for builtin modules Create file module.builtin.ranges that can be used to find where built-in modules are located by their addresses. This will be useful for tracing tools to find what functions are for various built-in modules. The offset range data for builtin modules is generated using: - modules.builtin: associates object files with module names - vmlinux.map: provides load order of sections and offset of first member per section - vmlinux.o.map: provides offset of object file content per section - .*.cmd: build cmd file with KBUILD_MODFILE The generated data will look like: .text 00000000-00000000 = _text .text 0000baf0-0000cb10 amd_uncore .text 0009bd10-0009c8e0 iosf_mbi ... .text 00b9f080-00ba011a intel_skl_int3472_discrete .text 00ba0120-00ba03c0 intel_skl_int3472_discrete intel_skl_int3472_tps68470 .text 00ba03c0-00ba08d6 intel_skl_int3472_tps68470 ... .data 00000000-00000000 = _sdata .data 0000f020-0000f680 amd_uncore For each ELF section, it lists the offset of the first symbol. This can be used to determine the base address of the section at runtime. Next, it lists (in strict ascending order) offset ranges in that section that cover the symbols of one or more builtin modules. Multiple ranges can apply to a single module, and ranges can be shared between modules. The CONFIG_BUILTIN_MODULE_RANGES option controls whether offset range data is generated for kernel modules that are built into the kernel image. How it works: 1. The modules.builtin file is parsed to obtain a list of built-in module names and their associated object names (the .ko file that the module would be in if it were a loadable module, hereafter referred to as <kmodfile>). This object name can be used to identify objects in the kernel compile because any C or assembler code that ends up into a built-in module will have the option -DKBUILD_MODFILE=<kmodfile> present in its build command, and those can be found in the .<obj>.cmd file in the kernel build tree. If an object is part of multiple modules, they will all be listed in the KBUILD_MODFILE option argument. This allows us to conclusively determine whether an object in the kernel build belong to any modules, and which. 2. The vmlinux.map is parsed next to determine the base address of each top level section so that all addresses into the section can be turned into offsets. This makes it possible to handle sections getting loaded at different addresses at system boot. We also determine an 'anchor' symbol at the beginning of each section to make it possible to calculate the true base address of a section at runtime (i.e. symbol address - symbol offset). We collect start addresses of sections that are included in the top level section. This is used when vmlinux is linked using vmlinux.o, because in that case, we need to look at the vmlinux.o linker map to know what object a symbol is found in. And finally, we process each symbol that is listed in vmlinux.map (or vmlinux.o.map) based on the following structure: vmlinux linked from vmlinux.a: vmlinux.map: <top level section> <included section> -- might be same as top level section) <object> -- built-in association known <symbol> -- belongs to module(s) object belongs to ... vmlinux linked from vmlinux.o: vmlinux.map: <top level section> <included section> -- might be same as top level section) vmlinux.o -- need to use vmlinux.o.map <symbol> -- ignored ... vmlinux.o.map: <section> <object> -- built-in association known <symbol> -- belongs to module(s) object belongs to ... 3. As sections, objects, and symbols are processed, offset ranges are constructed in a straight-forward way: - If the symbol belongs to one or more built-in modules: - If we were working on the same module(s), extend the range to include this object - If we were working on another module(s), close that range, and start the new one - If the symbol does not belong to any built-in modules: - If we were working on a module(s) range, close that range Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com> Reviewed-by: Nick Alcock <nick.alcock@oracle.com> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Tested-by: Sam James <sam@gentoo.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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# module.builtin.ranges
# ---------------------------------------------------------------------------
ifdef CONFIG_BUILTIN_MODULE_RANGES
__default: modules.builtin.ranges
quiet_cmd_modules_builtin_ranges = GEN $@
cmd_modules_builtin_ranges = gawk -f $(real-prereqs) > $@
targets += modules.builtin.ranges
modules.builtin.ranges: $(srctree)/scripts/generate_builtin_ranges.awk \
modules.builtin vmlinux.map vmlinux.o.map FORCE
$(call if_changed,modules_builtin_ranges)
vmlinux.map: vmlinux
@:
endif
# Add FORCE to the prerequisites of a target to force it to be always rebuilt.
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# ---------------------------------------------------------------------------
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)