xref: /linux-6.15/Kbuild (revision 70a4fd6c) 
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 asm-offsets.h (may need bounds.h)
6# 3) Check for missing system calls
7
8# Default sed regexp - multiline due to syntax constraints
9define sed-y
10	"/^->/{s:->#\(.*\):/* \1 */:; \
11	s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
12	s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
13	s:->::; p;}"
14endef
15
16# Use filechk to avoid rebuilds when a header changes, but the resulting file
17# does not
18define filechk_offsets
19	(set -e; \
20	 echo "#ifndef $2"; \
21	 echo "#define $2"; \
22	 echo "/*"; \
23	 echo " * DO NOT MODIFY."; \
24	 echo " *"; \
25	 echo " * This file was generated by Kbuild"; \
26	 echo " */"; \
27	 echo ""; \
28	 sed -ne $(sed-y); \
29	 echo ""; \
30	 echo "#endif" )
31endef
32
33#####
34# 1) Generate bounds.h
35
36bounds-file := include/generated/bounds.h
37
38always  := $(bounds-file)
39targets := $(bounds-file) kernel/bounds.s
40
41# We use internal kbuild rules to avoid the "is up to date" message from make
42kernel/bounds.s: kernel/bounds.c FORCE
43	$(Q)mkdir -p $(dir $@)
44	$(call if_changed_dep,cc_s_c)
45
46$(obj)/$(bounds-file): kernel/bounds.s FORCE
47	$(call filechk,offsets,__LINUX_BOUNDS_H__)
48
49#####
50# 2) Generate asm-offsets.h
51#
52
53offsets-file := include/generated/asm-offsets.h
54
55always  += $(offsets-file)
56targets += $(offsets-file)
57targets += arch/$(SRCARCH)/kernel/asm-offsets.s
58
59# We use internal kbuild rules to avoid the "is up to date" message from make
60arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
61                                      $(obj)/$(bounds-file) FORCE
62	$(Q)mkdir -p $(dir $@)
63	$(call if_changed_dep,cc_s_c)
64
65$(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
66	$(call filechk,offsets,__ASM_OFFSETS_H__)
67
68#####
69# 3) Check for missing system calls
70#
71
72always += missing-syscalls
73targets += missing-syscalls
74
75quiet_cmd_syscalls = CALL    $<
76      cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)
77
78missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
79	$(call cmd,syscalls)
80
81# Keep these two files during make clean
82no-clean-files := $(bounds-file) $(offsets-file)
83