#!/bin/sh

  # SPDX-License-Identifier: GPL-2.0

  #
  # link vmlinux
  #
  # vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_INIT) and

  # $(KBUILD_VMLINUX_MAIN) and $(KBUILD_VMLINUX_LIBS). Most are built-in.a files

  # from top-level directories in the kernel tree, others are specified in
  # arch/$(ARCH)/Makefile. Ordering when linking is important, and
  # $(KBUILD_VMLINUX_INIT) must be first. $(KBUILD_VMLINUX_LIBS) are archives
  # which are linked conditionally (not within --whole-archive), and do not
  # require symbol indexes added.

  #
  # vmlinux
  #   ^
  #   |
  #   +-< $(KBUILD_VMLINUX_INIT)
  #   |   +--< init/version.o + more
  #   |
  #   +--< $(KBUILD_VMLINUX_MAIN)

  #   |    +--< drivers/built-in.a mm/built-in.a + more

  #   |

  #   +--< $(KBUILD_VMLINUX_LIBS)
  #   |    +--< lib/lib.a + more
  #   |

  #   +-< ${kallsymso} (see description in KALLSYMS section)
  #
  # vmlinux version (uname -v) cannot be updated during normal
  # descending-into-subdirs phase since we do not yet know if we need to
  # update vmlinux.
  # Therefore this step is delayed until just before final link of vmlinux.
  #
  # System.map is generated to document addresses of all kernel symbols
  
  # Error out on error
  set -e
  
  # Nice output in kbuild format
  # Will be supressed by "make -s"
  info()
  {
  	if [ "${quiet}" != "silent_" ]; then
  		printf "  %-7s %s
  " ${1} ${2}
  	fi
  }

  # Thin archive build here makes a final archive with symbol table and indexes
  # from vmlinux objects INIT and MAIN, which can be used as input to linker.
  # KBUILD_VMLINUX_LIBS archives should already have symbol table and indexes
  # added.

  #
  # Traditional incremental style of link does not require this step
  #

  # built-in.a output file

  #
  archive_builtin()
  {

  	info AR built-in.a
  	rm -f built-in.a;
  	${AR} rcsTP${KBUILD_ARFLAGS} built-in.a			\

  				${KBUILD_VMLINUX_INIT}		\
  				${KBUILD_VMLINUX_MAIN}

  }

  # Link of vmlinux.o used for section mismatch analysis
  # ${1} output file
  modpost_link()
  {

  	local objects

  	objects="--whole-archive				\

  		built-in.a					\

  		--no-whole-archive				\
  		--start-group					\
  		${KBUILD_VMLINUX_LIBS}				\
  		--end-group"

  	${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}

  }
  
  # Link of vmlinux
  # ${1} - optional extra .o files
  # ${2} - output file
  vmlinux_link()
  {
  	local lds="${objtree}/${KBUILD_LDS}"

  	local objects

  
  	if [ "${SRCARCH}" != "um" ]; then

  		objects="--whole-archive			\

  			built-in.a				\

  			--no-whole-archive			\
  			--start-group				\
  			${KBUILD_VMLINUX_LIBS}			\
  			--end-group				\
  			${1}"

  		${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}	\

  			-T ${lds} ${objects}

  	else

  		objects="-Wl,--whole-archive			\

  			built-in.a				\

  			-Wl,--no-whole-archive			\
  			-Wl,--start-group			\
  			${KBUILD_VMLINUX_LIBS}			\
  			-Wl,--end-group				\
  			${1}"

  		${CC} ${CFLAGS_vmlinux} -o ${2}			\
  			-Wl,-T,${lds}				\
  			${objects}				\

  			-lutil -lrt -lpthread

  		rm -f linux
  	fi
  }
  
  
  # Create ${2} .o file with all symbols from the ${1} object file
  kallsyms()
  {
  	info KSYM ${2}
  	local kallsymopt;
  
  	if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then

  		kallsymopt="${kallsymopt} --all-symbols"

  	fi

  	if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then

  		kallsymopt="${kallsymopt} --absolute-percpu"
  	fi

  	if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
  		kallsymopt="${kallsymopt} --base-relative"
  	fi

  	local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
  		      ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"

  	local afile="`basename ${2} .o`.S"
  
  	${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
  	${CC} ${aflags} -c -o ${2} ${afile}

  }
  
  # Create map file with all symbols from ${1}
  # See mksymap for additional details
  mksysmap()
  {
  	${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
  }

  sortextable()
  {
  	${objtree}/scripts/sortextable ${1}
  }

  # Delete output files in case of error

  cleanup()
  {

  	rm -f .tmp_System.map
  	rm -f .tmp_kallsyms*

  	rm -f .tmp_vmlinux*

  	rm -f built-in.a

  	rm -f System.map
  	rm -f vmlinux
  	rm -f vmlinux.o
  }

  on_exit()
  {
  	if [ $? -ne 0 ]; then
  		cleanup
  	fi
  }
  trap on_exit EXIT
  
  on_signals()
  {
  	exit 1
  }
  trap on_signals HUP INT QUIT TERM

  #
  #
  # Use "make V=1" to debug this script
  case "${KBUILD_VERBOSE}" in
  *1*)
  	set -x
  	;;
  esac
  
  if [ "$1" = "clean" ]; then
  	cleanup
  	exit 0
  fi
  
  # We need access to CONFIG_ symbols

  case "${KCONFIG_CONFIG}" in
  */*)
  	. "${KCONFIG_CONFIG}"
  	;;
  *)
  	# Force using a file from the current directory
  	. "./${KCONFIG_CONFIG}"
  esac

  # Update version
  info GEN .version

  if [ -r .version ]; then
  	VERSION=$(expr 0$(cat .version) + 1)
  	echo $VERSION > .version

  else

  	rm -f .version
  	echo 1 > .version

  fi;
  
  # final build of init/

  ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init

  archive_builtin
  
  #link vmlinux.o
  info LD vmlinux.o
  modpost_link vmlinux.o
  
  # modpost vmlinux.o to check for section mismatches
  ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o

  kallsymso=""
  kallsyms_vmlinux=""
  if [ -n "${CONFIG_KALLSYMS}" ]; then
  
  	# kallsyms support
  	# Generate section listing all symbols and add it into vmlinux
  	# It's a three step process:
  	# 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
  	#     but __kallsyms is empty.
  	#     Running kallsyms on that gives us .tmp_kallsyms1.o with
  	#     the right size
  	# 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
  	#     the right size, but due to the added section, some
  	#     addresses have shifted.
  	#     From here, we generate a correct .tmp_kallsyms2.o

  	# 3)  That link may have expanded the kernel image enough that
  	#     more linker branch stubs / trampolines had to be added, which
  	#     introduces new names, which further expands kallsyms. Do another
  	#     pass if that is the case. In theory it's possible this results
  	#     in even more stubs, but unlikely.
  	#     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
  	#     other bugs.
  	# 4)  The correct ${kallsymso} is linked into the final vmlinux.

  	#
  	# a)  Verify that the System.map from vmlinux matches the map from
  	#     ${kallsymso}.
  
  	kallsymso=.tmp_kallsyms2.o
  	kallsyms_vmlinux=.tmp_vmlinux2
  
  	# step 1
  	vmlinux_link "" .tmp_vmlinux1
  	kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
  
  	# step 2
  	vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
  	kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o

  	# step 3

  	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o)
  	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o)

  
  	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then

  		kallsymso=.tmp_kallsyms3.o
  		kallsyms_vmlinux=.tmp_vmlinux3
  
  		vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
  
  		kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
  	fi
  fi
  
  info LD vmlinux
  vmlinux_link "${kallsymso}" vmlinux

  if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
  	info SORTEX vmlinux
  	sortextable vmlinux
  fi

  info SYSMAP System.map
  mksysmap vmlinux System.map
  
  # step a (see comment above)
  if [ -n "${CONFIG_KALLSYMS}" ]; then
  	mksysmap ${kallsyms_vmlinux} .tmp_System.map
  
  	if ! cmp -s System.map .tmp_System.map; then

  		echo >&2 Inconsistent kallsyms data

  		echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround

  		exit 1
  	fi
  fi