xref: /openbmc/linux/Kbuild (revision 3805e6a1) 
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# 5) Generate constants.py (may need bounds.h)
9
10# Default sed regexp - multiline due to syntax constraints
11define sed-y
12	"/^->/{s:->#\(.*\):/* \1 */:; \
13	s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
14	s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
15	s:->::; p;}"
16endef
17
18# Use filechk to avoid rebuilds when a header changes, but the resulting file
19# does not
20define filechk_offsets
21	(set -e; \
22	 echo "#ifndef $2"; \
23	 echo "#define $2"; \
24	 echo "/*"; \
25	 echo " * DO NOT MODIFY."; \
26	 echo " *"; \
27	 echo " * This file was generated by Kbuild"; \
28	 echo " */"; \
29	 echo ""; \
30	 sed -ne $(sed-y); \
31	 echo ""; \
32	 echo "#endif" )
33endef
34
35#####
36# 1) Generate bounds.h
37
38bounds-file := include/generated/bounds.h
39
40always  := $(bounds-file)
41targets := kernel/bounds.s
42
43# We use internal kbuild rules to avoid the "is up to date" message from make
44kernel/bounds.s: kernel/bounds.c FORCE
45	$(Q)mkdir -p $(dir $@)
46	$(call if_changed_dep,cc_s_c)
47
48$(obj)/$(bounds-file): kernel/bounds.s FORCE
49	$(call filechk,offsets,__LINUX_BOUNDS_H__)
50
51#####
52# 2) Generate timeconst.h
53
54timeconst-file := include/generated/timeconst.h
55
56targets += $(timeconst-file)
57
58quiet_cmd_gentimeconst = GEN     $@
59define cmd_gentimeconst
60	(echo $(CONFIG_HZ) | bc -q $< ) > $@
61endef
62define filechk_gentimeconst
63	(echo $(CONFIG_HZ) | bc -q $< )
64endef
65
66$(obj)/$(timeconst-file): kernel/time/timeconst.bc FORCE
67	$(call filechk,gentimeconst)
68
69#####
70# 3) Generate asm-offsets.h
71#
72
73offsets-file := include/generated/asm-offsets.h
74
75always  += $(offsets-file)
76targets += arch/$(SRCARCH)/kernel/asm-offsets.s
77
78# We use internal kbuild rules to avoid the "is up to date" message from make
79arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
80                                      $(obj)/$(timeconst-file) $(obj)/$(bounds-file) FORCE
81	$(Q)mkdir -p $(dir $@)
82	$(call if_changed_dep,cc_s_c)
83
84$(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
85	$(call filechk,offsets,__ASM_OFFSETS_H__)
86
87#####
88# 4) Check for missing system calls
89#
90
91always += missing-syscalls
92targets += missing-syscalls
93
94quiet_cmd_syscalls = CALL    $<
95      cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)
96
97missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
98	$(call cmd,syscalls)
99
100#####
101# 5) Generate constants for Python GDB integration
102#
103
104extra-$(CONFIG_GDB_SCRIPTS) += build_constants_py
105
106build_constants_py: $(obj)/$(timeconst-file) $(obj)/$(bounds-file)
107	@$(MAKE) $(build)=scripts/gdb/linux $@
108
109# Keep these three files during make clean
110no-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)
111