xref: /openbmc/linux/Kbuild (revision a2cce7a9) 
1#
2# Kbuild for top-level directory of the kernel
3# This file takes care of the following:
4# 1) Generate bounds.h
5# 2) Generate timeconst.h
6# 3) Generate asm-offsets.h (may need bounds.h and timeconst.h)
7# 4) Check for missing system calls
8
9# Default sed regexp - multiline due to syntax constraints
10define sed-y
11	"/^->/{s:->#\(.*\):/* \1 */:; \
12	s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
13	s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
14	s:->::; p;}"
15endef
16
17# Use filechk to avoid rebuilds when a header changes, but the resulting file
18# does not
19define filechk_offsets
20	(set -e; \
21	 echo "#ifndef $2"; \
22	 echo "#define $2"; \
23	 echo "/*"; \
24	 echo " * DO NOT MODIFY."; \
25	 echo " *"; \
26	 echo " * This file was generated by Kbuild"; \
27	 echo " */"; \
28	 echo ""; \
29	 sed -ne $(sed-y); \
30	 echo ""; \
31	 echo "#endif" )
32endef
33
34#####
35# 1) Generate bounds.h
36
37bounds-file := include/generated/bounds.h
38
39always  := $(bounds-file)
40targets := kernel/bounds.s
41
42# We use internal kbuild rules to avoid the "is up to date" message from make
43kernel/bounds.s: kernel/bounds.c FORCE
44	$(Q)mkdir -p $(dir $@)
45	$(call if_changed_dep,cc_s_c)
46
47$(obj)/$(bounds-file): kernel/bounds.s FORCE
48	$(call filechk,offsets,__LINUX_BOUNDS_H__)
49
50#####
51# 2) Generate timeconst.h
52
53timeconst-file := include/generated/timeconst.h
54
55targets += $(timeconst-file)
56
57quiet_cmd_gentimeconst = GEN     $@
58define cmd_gentimeconst
59	(echo $(CONFIG_HZ) | bc -q $< ) > $@
60endef
61define filechk_gentimeconst
62	(echo $(CONFIG_HZ) | bc -q $< )
63endef
64
65$(obj)/$(timeconst-file): kernel/time/timeconst.bc FORCE
66	$(call filechk,gentimeconst)
67
68#####
69# 3) Generate asm-offsets.h
70#
71
72offsets-file := include/generated/asm-offsets.h
73
74always  += $(offsets-file)
75targets += arch/$(SRCARCH)/kernel/asm-offsets.s
76
77# We use internal kbuild rules to avoid the "is up to date" message from make
78arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
79                                      $(obj)/$(timeconst-file) $(obj)/$(bounds-file) FORCE
80	$(Q)mkdir -p $(dir $@)
81	$(call if_changed_dep,cc_s_c)
82
83$(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
84	$(call filechk,offsets,__ASM_OFFSETS_H__)
85
86#####
87# 4) Check for missing system calls
88#
89
90always += missing-syscalls
91targets += missing-syscalls
92
93quiet_cmd_syscalls = CALL    $<
94      cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)
95
96missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
97	$(call cmd,syscalls)
98
99# Keep these three files during make clean
100no-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)
101