Re: [patch 2/8] Kbuild: Create a way to create preprocessor constants from C expressions

[Sam Ravnborg <sam@ravnborg.org>]

On Thu, Mar 06, 2008 at 02:43:53PM -0800, Christoph Lameter wrote:
> Hmmm.. Even after the Sam's fixes: I still have the recursion probblem 
> that include/linux/bounds.h needs to exist and provide some value for 
> the constants in order to create kernel/bounds.c. And kernel/bounds.c is 
> needed then to create bounds.s which creates bounds.h. Argh!

I could only come up with following hack. And too late to try more today.

It your test proves that it is OK then:
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

(But I had preferred the recursive dependency to be gone...)

	Sam

diff --git a/Kbuild b/Kbuild
index 1570d24..37a270f 100644
--- a/Kbuild
+++ b/Kbuild
@@ -2,18 +2,21 @@
 # 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
+# 2) Generate bounds.h
+# 3) Check for missing system calls
 
 #####
 # 1) Generate asm-offsets.h
 #
+# Note: We create a temporary empty bounds.h file to build asm-offsets.s
 
 offsets-file := include/asm-$(SRCARCH)/asm-offsets.h
+bounds-file  := include/linux/bounds.h
 
-always  := $(offsets-file)
+always  := $(bounds-file) $(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
@@ -42,6 +45,7 @@ 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
 	$(Q)mkdir -p $(dir $@)
+	$(Q)test -f $(bounds-file) || (mkdir -p $(dir $(bounds-file)) && touch $(bounds-file))
 	$(call if_changed_dep,cc_s_c)
 
 $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild
@@ -49,7 +53,39 @@ $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild
 	$(call cmd,offsets)
 
 #####
-# 2) Check for missing system calls
+# 2) Generate 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 $(obj)/$(offsets-file) 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)
+
+#####
+# 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))
+

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