Kbuild

   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
  10 define sed-y
  11         "/^->/{s:->#\(.*\):/* \1 */:; \
  12         s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
  13         s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
  14         s:->::; p;}"
  15 endef
  16
  17 # Use filechk to avoid rebuilds when a header changes, but the resulting file
  18 # does not
  19 define 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" )
  32 endef
  33
  34 #####
  35 # 1) Generate bounds.h
  36
  37 bounds-file := include/generated/bounds.h
  38
  39 always  := $(bounds-file)
  40 targets := kernel/bounds.s
  41
  42 # We use internal kbuild rules to avoid the "is up to date" message from make
  43 kernel/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
  53 timeconst-file := include/generated/timeconst.h
  54
  55 #always  += $(timeconst-file)
  56 targets += $(timeconst-file)
  57
  58 quiet_cmd_gentimeconst = GEN     $@
  59 define cmd_gentimeconst
  60         (echo $(CONFIG_HZ) | bc -q $< ) > $@
  61 endef
  62 define filechk_gentimeconst
  63         (echo $(CONFIG_HZ) | bc -q $< )
  64 endef
  65
  66 $(obj)/$(timeconst-file): kernel/time/timeconst.bc FORCE
  67         $(call filechk,gentimeconst)
  68
  69 #####
  70 # 3) Generate asm-offsets.h
  71 #
  72
  73 offsets-file := include/generated/asm-offsets.h
  74
  75 always  += $(offsets-file)
  76 targets += arch/$(SRCARCH)/kernel/asm-offsets.s
  77
  78 # We use internal kbuild rules to avoid the "is up to date" message from make
  79 arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(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
  91 always += missing-syscalls
  92 targets += missing-syscalls
  93
  94 quiet_cmd_syscalls = CALL    $<
  95       cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)
  96
  97 missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
  98         $(call cmd,syscalls)
  99
 100 # Keep these three files during make clean
 101 no-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)