kbuild: create a way to create preprocessor constants from C expressions
The use of enums create constants that are not available to the preprocessor when building the kernel (f.e. MAX_NR_ZONES). Arch code already has a way to export constants calculated to the preprocessor through the asm-offsets.c file. Generate something similar for the core kernel through kbuild. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Родитель
308c05e35e
Коммит
1cdf25d704
56
Kbuild
56
Kbuild
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@ -1,19 +1,54 @@
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#
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# Kbuild for top-level directory of the kernel
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# This file takes care of the following:
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# 1) Generate asm-offsets.h
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# 2) Check for missing system calls
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# 1) Generate bounds.h
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# 2) Generate asm-offsets.h (may need bounds.h)
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# 3) Check for missing system calls
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#####
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# 1) Generate asm-offsets.h
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# 1) Generate bounds.h
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bounds-file := include/linux/bounds.h
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always := $(bounds-file)
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targets := $(bounds-file) kernel/bounds.s
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quiet_cmd_bounds = GEN $@
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define cmd_bounds
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(set -e; \
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echo "#ifndef __LINUX_BOUNDS_H__"; \
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echo "#define __LINUX_BOUNDS_H__"; \
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echo "/*"; \
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echo " * DO NOT MODIFY."; \
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echo " *"; \
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echo " * This file was generated by Kbuild"; \
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echo " *"; \
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echo " */"; \
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echo ""; \
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sed -ne $(sed-y) $<; \
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echo ""; \
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echo "#endif" ) > $@
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endef
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# We use internal kbuild rules to avoid the "is up to date" message from make
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kernel/bounds.s: kernel/bounds.c FORCE
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$(Q)mkdir -p $(dir $@)
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$(call if_changed_dep,cc_s_c)
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$(obj)/$(bounds-file): kernel/bounds.s Kbuild
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$(Q)mkdir -p $(dir $@)
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$(call cmd,bounds)
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#####
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# 2) Generate asm-offsets.h
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#
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offsets-file := include/asm-$(SRCARCH)/asm-offsets.h
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always := $(offsets-file)
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targets := $(offsets-file)
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always += $(offsets-file)
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targets += $(offsets-file)
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targets += arch/$(SRCARCH)/kernel/asm-offsets.s
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clean-files := $(addprefix $(objtree)/,$(targets))
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# Default sed regexp - multiline due to syntax constraints
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define sed-y
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@ -40,7 +75,8 @@ define cmd_offsets
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endef
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# We use internal kbuild rules to avoid the "is up to date" message from make
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arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c FORCE
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arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
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$(obj)/$(bounds-file) FORCE
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$(Q)mkdir -p $(dir $@)
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$(call if_changed_dep,cc_s_c)
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@ -49,7 +85,7 @@ $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild
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$(call cmd,offsets)
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#####
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# 2) Check for missing system calls
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# 3) Check for missing system calls
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#
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quiet_cmd_syscalls = CALL $<
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@ -58,3 +94,7 @@ quiet_cmd_syscalls = CALL $<
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PHONY += missing-syscalls
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missing-syscalls: scripts/checksyscalls.sh FORCE
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$(call cmd,syscalls)
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# Delete all targets during make clean
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clean-files := $(addprefix $(objtree)/,$(targets))
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@ -0,0 +1,19 @@
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/*
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* Generate definitions needed by the preprocessor.
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* This code generates raw asm output which is post-processed
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* to extract and format the required data.
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*/
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#define __GENERATING_BOUNDS_H
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/* Include headers that define the enum constants of interest */
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#define DEFINE(sym, val) \
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asm volatile("\n->" #sym " %0 " #val : : "i" (val))
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#define BLANK() asm volatile("\n->" : : )
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void foo(void)
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{
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/* The enum constants to put into include/linux/bounds.h */
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/* End of constants */
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}
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