linux-4.20.0-rc2/Kbuild

1 # SPDX-License-Identifier: GPL-2.0
2 #
3 # Kbuild for top-level directory of the kernel
4 # This file takes care of the following:
5 # 1) Generate bounds.h
6 # 2) Generate timeconst.h
7 # 3) Generate asm-offsets.h (may need bounds.h and timeconst.h)
8 # 4) Check for missing system calls
9 # 5) Generate constants.py (may need bounds.h)
10 
11 #####
12 # 1) Generate bounds.h
13 
14 bounds-file := include/generated/bounds.h
15 
16 always  := $(bounds-file)
17 targets := kernel/bounds.s
18 
19 # We use internal kbuild rules to avoid the "is up to date" message from make
20 kernel/bounds.s: kernel/bounds.c FORCE
21 	$(call if_changed_dep,cc_s_c)
22 
23 $(obj)/$(bounds-file): kernel/bounds.s FORCE
24 	$(call filechk,offsets,__LINUX_BOUNDS_H__)
25 
26 #####
27 # 2) Generate timeconst.h
28 
29 timeconst-file := include/generated/timeconst.h
30 
31 targets += $(timeconst-file)
32 
33 quiet_cmd_gentimeconst = GEN     $@
34 define cmd_gentimeconst
35 	(echo $(CONFIG_HZ) | bc -q $< ) > $@
36 endef
37 define filechk_gentimeconst
38 	(echo $(CONFIG_HZ) | bc -q $< )
39 endef
40 
41 $(obj)/$(timeconst-file): kernel/time/timeconst.bc FORCE
42 	$(call filechk,gentimeconst)
43 
44 #####
45 # 3) Generate asm-offsets.h
46 #
47 
48 offsets-file := include/generated/asm-offsets.h
49 
50 always  += $(offsets-file)
51 targets += arch/$(SRCARCH)/kernel/asm-offsets.s
52 
53 # We use internal kbuild rules to avoid the "is up to date" message from make
54 arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
55                                       $(obj)/$(timeconst-file) $(obj)/$(bounds-file) FORCE
56 	$(call if_changed_dep,cc_s_c)
57 
58 $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
59 	$(call filechk,offsets,__ASM_OFFSETS_H__)
60 
61 #####
62 # 4) Check for missing system calls
63 #
64 
65 always += missing-syscalls
66 targets += missing-syscalls
67 
68 quiet_cmd_syscalls = CALL    $<
69       cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)
70 
71 missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
72 	$(call cmd,syscalls)
73 
74 #####
75 # 5) Generate constants for Python GDB integration
76 #
77 
78 extra-$(CONFIG_GDB_SCRIPTS) += build_constants_py
79 
80 build_constants_py: $(obj)/$(timeconst-file) $(obj)/$(bounds-file)
81 	@$(MAKE) $(build)=scripts/gdb/linux $@
82 
83 # Keep these three files during make clean
84 no-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)