kbuild: create a way to create preprocessor constants from C expressions (1cdf25d7) · Commits · 戴 / test

Kbuild

+48 −8

Original line number	Diff line number	Diff line
		#
		# Kbuild for top-level directory of the kernel
		# This file takes care of the following:
		# 1) Generate asm-offsets.h
		# 2) Check for missing system calls
		# 1) Generate bounds.h
		# 2) Generate asm-offsets.h (may need bounds.h)
		# 3) Check for missing system calls

		#####
		# 1) Generate asm-offsets.h
		# 1) Generate bounds.h

		bounds-file := include/linux/bounds.h

		always := $(bounds-file)
		targets := $(bounds-file) kernel/bounds.s

		quiet_cmd_bounds = GEN $@
		define cmd_bounds
		(set -e; \
		echo "#ifndef __LINUX_BOUNDS_H__"; \
		echo "#define __LINUX_BOUNDS_H__"; \
		echo "/*"; \
		echo " * DO NOT MODIFY."; \
		echo " *"; \
		echo " * This file was generated by Kbuild"; \
		echo " *"; \
		echo " */"; \
		echo ""; \
		sed -ne $(sed-y) $<; \
		echo ""; \
		echo "#endif" ) > $@
		endef

		# We use internal kbuild rules to avoid the "is up to date" message from make
		kernel/bounds.s: kernel/bounds.c FORCE
		$(Q)mkdir -p $(dir $@)
		$(call if_changed_dep,cc_s_c)

		$(obj)/$(bounds-file): kernel/bounds.s Kbuild
		$(Q)mkdir -p $(dir $@)
		$(call cmd,bounds)

		#####
		# 2) Generate asm-offsets.h
		#

		offsets-file := include/asm-$(SRCARCH)/asm-offsets.h

		always := $(offsets-file)
		targets := $(offsets-file)
		always += $(offsets-file)
		targets += $(offsets-file)
		targets += arch/$(SRCARCH)/kernel/asm-offsets.s
		clean-files := $(addprefix $(objtree)/,$(targets))


		# Default sed regexp - multiline due to syntax constraints
		define sed-y
		@@ -40,7 +75,8 @@ define cmd_offsets
		endef

		# We use internal kbuild rules to avoid the "is up to date" message from make
		arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c FORCE
		arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
		$(obj)/$(bounds-file) FORCE
		$(Q)mkdir -p $(dir $@)
		$(call if_changed_dep,cc_s_c)

		@@ -49,7 +85,7 @@ $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild
		$(call cmd,offsets)

		#####
		# 2) Check for missing system calls
		# 3) Check for missing system calls
		#

		quiet_cmd_syscalls = CALL $<
		@@ -58,3 +94,7 @@ quiet_cmd_syscalls = CALL $<
		PHONY += missing-syscalls
		missing-syscalls: scripts/checksyscalls.sh FORCE
		$(call cmd,syscalls)

		# Delete all targets during make clean
		clean-files := $(addprefix $(objtree)/,$(targets))

kernel/bounds.c

0 → 100644

+19 −0

Original line number	Diff line number	Diff line
		/*
		* Generate definitions needed by the preprocessor.
		* This code generates raw asm output which is post-processed
		* to extract and format the required data.
		*/

		#define __GENERATING_BOUNDS_H
		/* Include headers that define the enum constants of interest */

		#define DEFINE(sym, val) \
		asm volatile("\n->" #sym " %0 " #val : : "i" (val))

		#define BLANK() asm volatile("\n->" : : )

		void foo(void)
		{
		/* The enum constants to put into include/linux/bounds.h */
		/* End of constants */
		}

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