09bd7c75e5
One of the most remarkable improvements in this cycle is, Kbuild is now able to cache the result of shell commands. Some variables are expensive to compute, for example, $(call cc-option,...) invokes the compiler. It is not efficient to redo this computation every time, even when we are not actually building anything. Kbuild creates a hidden file ".cache.mk" that contains invoked shell commands and their results. The speed-up should be noticeable. Summary: - Fix arch build issues (hexagon, sh) - Clean up various Makefiles and scripts - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles - Cache variables that are expensive to compute - Improve cc-ldopton and ld-option for Clang - Optimize output directory creation -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJaDxaLAAoJED2LAQed4NsGIHQP/isMxxaIxIAWU56+ZcII74k7 639VgrKi9n5y25d1dBRTQg+vReHE6E2JbkCqpVOu11t7m0LT7yUK8v3WwyLf1qTN GxnqZ/WMQU5/AYVqIWo8jN4FGHpivHJ6qbeiNJM9qN4RAkzG0sZUq746VaFZYmIR Lu0Gf4m4qjifkkhXsQdWT5i7yNTidPqaL6GNb+FcFkEHlVre8jma0kJlgfHxru84 WmETpjQXvHAZ/R61vY6ekAWpqFhw3ecJY96A9npnx+SQVQdSNAdpaU0SK29jB0ON /SAfpHg9oa/gD0LFOKV6zkjnAkd4TEjrJEiHHhz5gjT/SbS3T1llBIGZ1oV4X7Y0 Vlh9KWlm1FJJI4SIzc9qUaQMp6JtLfEfHKJCc45xVaN3fNrDnR8jl80x5+95ELga dCkZgnq5u82MtTysCbHBESwDYQaVPyIrh7In+mduglaCqhqj9KoDjoLoiGfCg7SA 3tPflYVd629w5l5GrazJ40jWn1+ggMtgMOVooJNJ+dINCP+GxsUpH84Ww2Pdic+/ qLdud6TeqxrZDGzWXqKNLu8alM8NGgSr101l9gIf1oqSyy63duBpMrxGDoIJS3FU rFDoFFUhlfkAXNbQHtVGNzKtcpCjURh992j9Fa1+NfMwSce5IHkMwTvPmNSRowi8 0llLjXhD/bxK6FpdvlV8 =zIdO -----END PGP SIGNATURE----- Merge tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: "One of the most remarkable improvements in this cycle is, Kbuild is now able to cache the result of shell commands. Some variables are expensive to compute, for example, $(call cc-option,...) invokes the compiler. It is not efficient to redo this computation every time, even when we are not actually building anything. Kbuild creates a hidden file ".cache.mk" that contains invoked shell commands and their results. The speed-up should be noticeable. Summary: - Fix arch build issues (hexagon, sh) - Clean up various Makefiles and scripts - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles - Cache variables that are expensive to compute - Improve cc-ldopton and ld-option for Clang - Optimize output directory creation" * tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits) kbuild: move coccicheck help from scripts/Makefile.help to top Makefile sh: decompressor: add shipped files to .gitignore frv: .gitignore: ignore vmlinux.lds selinux: remove unnecessary assignment to subdir- kbuild: specify FORCE in Makefile.headersinst as .PHONY target kbuild: remove redundant mkdir from ./Kbuild kbuild: optimize object directory creation for incremental build kbuild: create object directories simpler and faster kbuild: filter-out PHONY targets from "targets" kbuild: remove redundant $(wildcard ...) for cmd_files calculation kbuild: create directory for make cache only when necessary sh: select KBUILD_DEFCONFIG depending on ARCH kbuild: fix linker feature test macros when cross compiling with Clang kbuild: shrink .cache.mk when it exceeds 1000 lines kbuild: do not call cc-option before KBUILD_CFLAGS initialization kbuild: Cache a few more calls to the compiler kbuild: Add a cache for generated variables kbuild: add forward declaration of default target to Makefile.asm-generic kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE ...
332 lines
7.6 KiB
Bash
Executable file
332 lines
7.6 KiB
Bash
Executable file
#!/bin/sh
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# SPDX-License-Identifier: GPL-2.0
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#
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# link vmlinux
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#
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# vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_INIT) and
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# $(KBUILD_VMLINUX_MAIN) and $(KBUILD_VMLINUX_LIBS). Most are built-in.o files
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# from top-level directories in the kernel tree, others are specified in
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# arch/$(ARCH)/Makefile. Ordering when linking is important, and
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# $(KBUILD_VMLINUX_INIT) must be first. $(KBUILD_VMLINUX_LIBS) are archives
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# which are linked conditionally (not within --whole-archive), and do not
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# require symbol indexes added.
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#
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# vmlinux
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# ^
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# |
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# +-< $(KBUILD_VMLINUX_INIT)
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# | +--< init/version.o + more
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# |
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# +--< $(KBUILD_VMLINUX_MAIN)
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# | +--< drivers/built-in.o mm/built-in.o + more
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# |
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# +--< $(KBUILD_VMLINUX_LIBS)
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# | +--< lib/lib.a + more
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# |
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# +-< ${kallsymso} (see description in KALLSYMS section)
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#
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# vmlinux version (uname -v) cannot be updated during normal
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# descending-into-subdirs phase since we do not yet know if we need to
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# update vmlinux.
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# Therefore this step is delayed until just before final link of vmlinux.
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#
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# System.map is generated to document addresses of all kernel symbols
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# Error out on error
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set -e
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# Nice output in kbuild format
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# Will be supressed by "make -s"
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info()
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{
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if [ "${quiet}" != "silent_" ]; then
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printf " %-7s %s\n" ${1} ${2}
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fi
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}
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# Thin archive build here makes a final archive with symbol table and indexes
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# from vmlinux objects INIT and MAIN, which can be used as input to linker.
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# KBUILD_VMLINUX_LIBS archives should already have symbol table and indexes
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# added.
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#
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# Traditional incremental style of link does not require this step
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#
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# built-in.o output file
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#
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archive_builtin()
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{
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if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
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info AR built-in.o
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rm -f built-in.o;
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${AR} rcsTP${KBUILD_ARFLAGS} built-in.o \
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${KBUILD_VMLINUX_INIT} \
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${KBUILD_VMLINUX_MAIN}
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fi
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}
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# Link of vmlinux.o used for section mismatch analysis
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# ${1} output file
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modpost_link()
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{
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local objects
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if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
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objects="--whole-archive \
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built-in.o \
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--no-whole-archive \
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--start-group \
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${KBUILD_VMLINUX_LIBS} \
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--end-group"
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else
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objects="${KBUILD_VMLINUX_INIT} \
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--start-group \
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${KBUILD_VMLINUX_MAIN} \
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${KBUILD_VMLINUX_LIBS} \
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--end-group"
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fi
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${LD} ${LDFLAGS} -r -o ${1} ${objects}
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}
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# Link of vmlinux
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# ${1} - optional extra .o files
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# ${2} - output file
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vmlinux_link()
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{
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local lds="${objtree}/${KBUILD_LDS}"
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local objects
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if [ "${SRCARCH}" != "um" ]; then
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if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
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objects="--whole-archive \
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built-in.o \
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--no-whole-archive \
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--start-group \
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${KBUILD_VMLINUX_LIBS} \
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--end-group \
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${1}"
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else
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objects="${KBUILD_VMLINUX_INIT} \
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--start-group \
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${KBUILD_VMLINUX_MAIN} \
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${KBUILD_VMLINUX_LIBS} \
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--end-group \
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${1}"
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fi
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${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \
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-T ${lds} ${objects}
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else
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if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
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objects="-Wl,--whole-archive \
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built-in.o \
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-Wl,--no-whole-archive \
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-Wl,--start-group \
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${KBUILD_VMLINUX_LIBS} \
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-Wl,--end-group \
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${1}"
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else
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objects="${KBUILD_VMLINUX_INIT} \
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-Wl,--start-group \
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${KBUILD_VMLINUX_MAIN} \
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${KBUILD_VMLINUX_LIBS} \
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-Wl,--end-group \
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${1}"
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fi
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${CC} ${CFLAGS_vmlinux} -o ${2} \
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-Wl,-T,${lds} \
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${objects} \
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-lutil -lrt -lpthread
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rm -f linux
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fi
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}
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# Create ${2} .o file with all symbols from the ${1} object file
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kallsyms()
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{
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info KSYM ${2}
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local kallsymopt;
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if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
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kallsymopt="${kallsymopt} --symbol-prefix=_"
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fi
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if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
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kallsymopt="${kallsymopt} --all-symbols"
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fi
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if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
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kallsymopt="${kallsymopt} --absolute-percpu"
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fi
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if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
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kallsymopt="${kallsymopt} --base-relative"
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fi
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local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
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${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
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local afile="`basename ${2} .o`.S"
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${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
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${CC} ${aflags} -c -o ${2} ${afile}
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}
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# Create map file with all symbols from ${1}
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# See mksymap for additional details
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mksysmap()
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{
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${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
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}
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sortextable()
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{
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${objtree}/scripts/sortextable ${1}
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}
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# Delete output files in case of error
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cleanup()
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{
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rm -f .tmp_System.map
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rm -f .tmp_kallsyms*
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rm -f .tmp_vmlinux*
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rm -f built-in.o
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rm -f System.map
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rm -f vmlinux
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rm -f vmlinux.o
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}
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on_exit()
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{
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if [ $? -ne 0 ]; then
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cleanup
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fi
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}
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trap on_exit EXIT
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on_signals()
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{
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exit 1
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}
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trap on_signals HUP INT QUIT TERM
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#
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#
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# Use "make V=1" to debug this script
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case "${KBUILD_VERBOSE}" in
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*1*)
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set -x
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;;
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esac
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if [ "$1" = "clean" ]; then
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cleanup
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exit 0
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fi
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# We need access to CONFIG_ symbols
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case "${KCONFIG_CONFIG}" in
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*/*)
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. "${KCONFIG_CONFIG}"
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;;
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*)
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# Force using a file from the current directory
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. "./${KCONFIG_CONFIG}"
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esac
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# Update version
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info GEN .version
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if [ -r .version ]; then
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VERSION=$(expr 0$(cat .version) + 1)
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echo $VERSION > .version
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else
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rm -f .version
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echo 1 > .version
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fi;
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# final build of init/
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${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init GCC_PLUGINS_CFLAGS="${GCC_PLUGINS_CFLAGS}"
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archive_builtin
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#link vmlinux.o
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info LD vmlinux.o
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modpost_link vmlinux.o
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# modpost vmlinux.o to check for section mismatches
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${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
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kallsymso=""
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kallsyms_vmlinux=""
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if [ -n "${CONFIG_KALLSYMS}" ]; then
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# kallsyms support
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# Generate section listing all symbols and add it into vmlinux
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# It's a three step process:
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# 1) Link .tmp_vmlinux1 so it has all symbols and sections,
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# but __kallsyms is empty.
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# Running kallsyms on that gives us .tmp_kallsyms1.o with
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# the right size
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# 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
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# the right size, but due to the added section, some
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# addresses have shifted.
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# From here, we generate a correct .tmp_kallsyms2.o
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# 3) That link may have expanded the kernel image enough that
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# more linker branch stubs / trampolines had to be added, which
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# introduces new names, which further expands kallsyms. Do another
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# pass if that is the case. In theory it's possible this results
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# in even more stubs, but unlikely.
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# KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
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# other bugs.
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# 4) The correct ${kallsymso} is linked into the final vmlinux.
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#
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# a) Verify that the System.map from vmlinux matches the map from
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# ${kallsymso}.
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kallsymso=.tmp_kallsyms2.o
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kallsyms_vmlinux=.tmp_vmlinux2
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# step 1
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vmlinux_link "" .tmp_vmlinux1
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kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
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# step 2
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vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
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kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
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# step 3
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size1=$(stat -c "%s" .tmp_kallsyms1.o)
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size2=$(stat -c "%s" .tmp_kallsyms2.o)
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if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
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kallsymso=.tmp_kallsyms3.o
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kallsyms_vmlinux=.tmp_vmlinux3
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vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
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kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
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fi
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fi
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info LD vmlinux
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vmlinux_link "${kallsymso}" vmlinux
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if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
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info SORTEX vmlinux
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sortextable vmlinux
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fi
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info SYSMAP System.map
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mksysmap vmlinux System.map
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# step a (see comment above)
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if [ -n "${CONFIG_KALLSYMS}" ]; then
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mksysmap ${kallsyms_vmlinux} .tmp_System.map
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if ! cmp -s System.map .tmp_System.map; then
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echo >&2 Inconsistent kallsyms data
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echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
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exit 1
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fi
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fi
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