## 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 constraintsdefine 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 notdefine 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 makekernel/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 $< ) > $@endefdefine 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 makearch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(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-syscallstargets += 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 cleanno-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)