[PATCH v3] kbuild: simpler generation of assembly constants

From: Alexey Dobriyan
Date: Wed Jul 13 2016 - 13:37:44 EST


gcc doesn't really look inside "asm" statements and more or less
directly emits it into assembly. So pretend "#define" is CPU
instruction.

C++ comment can't be used because sparc assembler doesn't understand it.

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

This one compiles on Sparc and UML.

Kbuild | 12 +-----------
arch/ia64/kernel/Makefile | 8 +-------
arch/um/Makefile | 2 +-
arch/x86/um/shared/sysdep/kernel-offsets.h | 2 +-
arch/x86/um/user-offsets.c | 4 ++--
include/linux/kbuild.h | 2 +-
scripts/mod/Makefile | 11 +----------
7 files changed, 8 insertions(+), 33 deletions(-)

--- a/Kbuild
+++ b/Kbuild
@@ -7,14 +7,6 @@
# 4) Check for missing system calls
# 5) Generate constants.py (may need bounds.h)

-# Default sed regexp - multiline due to syntax constraints
-define sed-y
- "/^->/{s:->#\(.*\):/* \1 */:; \
- s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
- s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
- s:->::; p;}"
-endef
-
# Use filechk to avoid rebuilds when a header changes, but the resulting file
# does not
define filechk_offsets
@@ -26,9 +18,7 @@ define filechk_offsets
echo " *"; \
echo " * This file was generated by Kbuild"; \
echo " */"; \
- echo ""; \
- sed -ne $(sed-y); \
- echo ""; \
+ sed -ne '/#define/{s/\$$//;s/#//2;s/$$/*\//;p;}'; \
echo "#endif" )
endef

--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -50,10 +50,6 @@ CFLAGS_traps.o += -mfixed-range=f2-f5,f16-f31
# The gate DSO image is built using a special linker script.
include $(src)/Makefile.gate

-# Calculate NR_IRQ = max(IA64_NATIVE_NR_IRQS, XEN_NR_IRQS, ...) based on config
-define sed-y
- "/^->/{s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; s:->::; p;}"
-endef
quiet_cmd_nr_irqs = GEN $@
define cmd_nr_irqs
(set -e; \
@@ -65,9 +61,7 @@ define cmd_nr_irqs
echo " * This file was generated by Kbuild"; \
echo " *"; \
echo " */"; \
- echo ""; \
- sed -ne $(sed-y) $<; \
- echo ""; \
+ sed -ne '/#define/{s/\$$//;s/#//2;s/$$/*\//p;}' $<; \
echo "#endif" ) > $@
endef

--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -158,7 +158,7 @@ define filechk_gen-asm-offsets
echo " *"; \
echo " */"; \
echo ""; \
- sed -ne "/^->/{s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; s:->::; p;}"; \
+ sed -ne '/#define/{s/\$$//;s/#//2;s/$$/*\//p;}'; \
echo ""; )
endef

--- a/arch/x86/um/shared/sysdep/kernel-offsets.h
+++ b/arch/x86/um/shared/sysdep/kernel-offsets.h
@@ -5,7 +5,7 @@
#include <asm/mman.h>

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

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

--- a/arch/x86/um/user-offsets.c
+++ b/arch/x86/um/user-offsets.c
@@ -21,10 +21,10 @@ static char syscalls[] = {
#endif

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

#define DEFINE_LONGS(sym, val) \
- asm volatile("\n->" #sym " %0 " #val : : "i" (val/sizeof(unsigned long)))
+ asm volatile ("#define " #sym " %0 /*" #val :: "i" (val / sizeof(unsigned long)))

void foo(void)
{
--- a/include/linux/kbuild.h
+++ b/include/linux/kbuild.h
@@ -2,7 +2,7 @@
#define __LINUX_KBUILD_H

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

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

--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@@ -7,13 +7,6 @@ modpost-objs := modpost.o file2alias.o sumversion.o

devicetable-offsets-file := devicetable-offsets.h

-define sed-y
- "/^->/{s:->#\(.*\):/* \1 */:; \
- s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
- s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
- s:->::; p;}"
-endef
-
quiet_cmd_offsets = GEN $@
define cmd_offsets
(set -e; \
@@ -25,9 +18,7 @@ define cmd_offsets
echo " * This file was generated by Kbuild"; \
echo " *"; \
echo " */"; \
- echo ""; \
- sed -ne $(sed-y) $<; \
- echo ""; \
+ sed -ne '/#define/{s/\$$//;s/#//2;s/$$/*\//;p;}' $<; \
echo "#endif" ) > $@
endef