#
  # Kbuild for top-level directory of the kernel
  # This file takes care of the following:

  # 1) Generate bounds.h

  # 2) Generate timeconst.h
  # 3) Generate asm-offsets.h (may need bounds.h and timeconst.h)
  # 4) Check for missing system calls

  # 5) Generate constants.py (may need bounds.h)

  # Default sed regexp - multiline due to syntax constraints
  define sed-y
  	"/^->/{s:->#\(.*\):/* \1 */:; \
  	s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
  	s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
  	s:->::; p;}"
  endef

  # Use filechk to avoid rebuilds when a header changes, but the resulting file
  # does not
  define filechk_offsets

  	(set -e; \

  	 echo "#ifndef $2"; \
  	 echo "#define $2"; \

  	 echo "/*"; \
  	 echo " * DO NOT MODIFY."; \
  	 echo " *"; \
  	 echo " * This file was generated by Kbuild"; \

  	 echo " */"; \
  	 echo ""; \

  	 sed -ne $(sed-y); \

  	 echo ""; \

  	 echo "#endif" )

  endef

  #####
  # 1) Generate bounds.h
  
  bounds-file := include/generated/bounds.h
  
  always  := $(bounds-file)

  targets := kernel/bounds.s

  # We use internal kbuild rules to avoid the "is up to date" message from make
  kernel/bounds.s: kernel/bounds.c FORCE
  	$(Q)mkdir -p $(dir $@)
  	$(call if_changed_dep,cc_s_c)

  $(obj)/$(bounds-file): kernel/bounds.s FORCE
  	$(call filechk,offsets,__LINUX_BOUNDS_H__)

  
  #####

  # 2) Generate timeconst.h
  
  timeconst-file := include/generated/timeconst.h

  targets += $(timeconst-file)
  
  quiet_cmd_gentimeconst = GEN     $@
  define cmd_gentimeconst
  	(echo $(CONFIG_HZ) | bc -q $< ) > $@
  endef
  define filechk_gentimeconst
  	(echo $(CONFIG_HZ) | bc -q $< )
  endef
  
  $(obj)/$(timeconst-file): kernel/time/timeconst.bc FORCE
  	$(call filechk,gentimeconst)
  
  #####
  # 3) Generate asm-offsets.h

  #

  offsets-file := include/generated/asm-offsets.h

  always  += $(offsets-file)

  targets += arch/$(SRCARCH)/kernel/asm-offsets.s

  # We use internal kbuild rules to avoid the "is up to date" message from make

  arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \

                                        $(obj)/$(timeconst-file) $(obj)/$(bounds-file) FORCE

  	$(Q)mkdir -p $(dir $@)
  	$(call if_changed_dep,cc_s_c)

  $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
  	$(call filechk,offsets,__ASM_OFFSETS_H__)

  #####

  # 4) Check for missing system calls

  #

  always += missing-syscalls
  targets += missing-syscalls

  quiet_cmd_syscalls = CALL    $<

        cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)

  missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE

  	$(call cmd,syscalls)

  #####
  # 5) Generate constants for Python GDB integration
  #
  
  extra-$(CONFIG_GDB_SCRIPTS) += build_constants_py
  
  build_constants_py: $(obj)/$(timeconst-file) $(obj)/$(bounds-file)
  	@$(MAKE) $(build)=scripts/gdb/linux $@

  # Keep these three files during make clean
  no-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)