[PATCH 1/3] kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line

Sam Ravnborg
2010-07-28T18:27:16Z

From 40d7c77aeafa6b17503ffdcf58fa01411972b0d1 Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@ravnborg.org>
Date: Wed, 28 Jul 2010 17:33:09 +0200
Subject: [PATCH 1/3] kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line

It is now possible to assign options to AS, CC and LD
on the command line - which is only used when building modules.

{A,C,LD}FLAGS_MODULE was all used both in the top-level Makefile
in the arch makefiles, thus users had no way to specify
additional options to AS, CC, LD when building modules
without overriding the original value.

Introduce a new set of variables KBUILD_{A,C,LD}FLAGS_MODULE
that is used by arch specific files and free up
{A,C,LD}FLAGS_MODULE so they can be assigned on
the command line.

All arch Makefiles that used the old variables has been updated.

Note: Previously we had a MODFLAGS variable for both
AS and CC. But in favour of consistency this was dropped.
So in some cases arch Makefile has one assignmnet replaced by
two assignmnets.

Note2: MODFLAGS was not documented and is dropped
without any notice. I do not expect much/any breakage
from this.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
---
Documentation/kbuild/kbuild.txt | 16 ++++++++++++++--
Documentation/kbuild/makefiles.txt | 18 +++++++++++++++---
Makefile | 13 ++++++++-----
arch/avr32/Makefile | 2 +-
arch/blackfin/Makefile | 4 ++--
arch/ia64/Makefile | 2 +-
arch/m32r/Makefile | 2 +-
arch/m68k/Makefile | 2 +-
arch/mips/Makefile | 6 ++++--
arch/powerpc/Makefile | 2 +-
arch/s390/Makefile | 3 ++-
arch/score/Makefile | 3 ++-
scripts/Makefile.build | 9 ++++++---
scripts/Makefile.modpost | 7 ++++---
14 files changed, 62 insertions(+), 27 deletions(-)

diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index 634c625..d9c6554 100644
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -22,11 +22,23 @@ building C files and assembler files.

KAFLAGS
--------------------------------------------------
-Additional options to the assembler.
+Additional options to the assembler (for built-in and modules).
+
+AFLAGS_MODULE
+--------------------------------------------------
+Addtional module specific options to use for $(AS).

KCFLAGS
--------------------------------------------------
-Additional options to the C compiler.
+Additional options to the C compiler (for built-in and modules).
+
+CFLAGS_MODULE
+--------------------------------------------------
+Addtional module specific options to use for $(CC).
+
+LDFLAGS_MODULE
+--------------------------------------------------
+Additional options used for $(LD) when linking modules.

KBUILD_VERBOSE
--------------------------------------------------
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index 71c602d..802341a 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -928,11 +928,23 @@ When kbuild executes, the following steps are followed (roughly):
$(CFLAGS_KERNEL) contains extra C compiler flags used to compile
resident kernel code.

- CFLAGS_MODULE $(CC) options specific for modules
+ KBUILD_AFLAGS_MODULE Options for $(AS) when building modules

- $(CFLAGS_MODULE) contains extra C compiler flags used to compile code
- for loadable kernel modules.
+ $(KBUILD_AFLAGS_MODULE) is used to add arch specific options that
+ are used for $(AS).
+ From commandline AFLAGS_MODULE shall be used (see kbuild.txt).

+ KBUILD_CFLAGS_MODULE Options for $(CC) when building modules
+
+ $(KBUILD_CFLAGS_MODULE) is used to add arch specific options that
+ are used for $(CC).
+ From commandline CFLAGS_MODULE shall be used (see kbuild.txt).
+
+ KBUILD_LDFLAGS_MODULE Options for $(LD) when linking modules
+
+ $(KBUILD_LDFLAGS_MODULE) is used to add arch specific options
+ used when linking modules. This is often a linker script.
+ From commandline LDFLAGS_MODULE shall be used (see kbuild.txt).

--- 6.2 Add prerequisites to archprepare:

diff --git a/Makefile b/Makefile
index a14c207..88447e7 100644
--- a/Makefile
+++ b/Makefile
@@ -332,10 +332,9 @@ CHECK = sparse

CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
-Wbitwise -Wno-return-void $(CF)
-MODFLAGS = -DMODULE
-CFLAGS_MODULE = $(MODFLAGS)
-AFLAGS_MODULE = $(MODFLAGS)
-LDFLAGS_MODULE = -T $(srctree)/scripts/module-common.lds
+CFLAGS_MODULE =
+AFLAGS_MODULE =
+LDFLAGS_MODULE =
CFLAGS_KERNEL =
AFLAGS_KERNEL =
CFLAGS_GCOV = -fprofile-arcs -ftest-coverage
@@ -355,6 +354,9 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-Wno-format-security \
-fno-delete-null-pointer-checks
KBUILD_AFLAGS := -D__ASSEMBLY__
+KBUILD_AFLAGS_MODULE := -DMODULE
+KBUILD_CFLAGS_MODULE := -DMODULE
+KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds

# Read KERNELRELEASE from include/config/kernel.release (if it exists)
KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
@@ -369,6 +371,7 @@ export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV
export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
+export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE

# When compiling out-of-tree modules, put MODVERDIR in the module
# tree rather than in the kernel tree. The kernel tree might
@@ -607,7 +610,7 @@ endif
# Use --build-id when available.
LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
$(call cc-ldoption, -Wl$(comma)--build-id,))
-LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
+KBUILD_LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)

ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
diff --git a/arch/avr32/Makefile b/arch/avr32/Makefile
index ead8a75..22fb665 100644
--- a/arch/avr32/Makefile
+++ b/arch/avr32/Makefile
@@ -13,7 +13,7 @@ KBUILD_DEFCONFIG := atstk1002_defconfig

KBUILD_CFLAGS += -pipe -fno-builtin -mno-pic
KBUILD_AFLAGS += -mrelax -mno-pic
-CFLAGS_MODULE += -mno-relax
+KBUILD_CFLAGS_MODULE += -mno-relax
LDFLAGS_vmlinux += --relax

cpuflags-$(CONFIG_PLATFORM_AT32AP) += -march=ap
diff --git a/arch/blackfin/Makefile b/arch/blackfin/Makefile
index 5a97a31..9d5ffaf 100644
--- a/arch/blackfin/Makefile
+++ b/arch/blackfin/Makefile
@@ -18,8 +18,8 @@ ifeq ($(CONFIG_ROMKERNEL),y)
KBUILD_CFLAGS += -mlong-calls
endif
KBUILD_AFLAGS += $(call cc-option,-mno-fdpic)
-CFLAGS_MODULE += -mlong-calls
-LDFLAGS_MODULE += -m elf32bfin
+KBUILD_CFLAGS_MODULE += -mlong-calls
+KBUILD_LDFLAGS_MODULE += -m elf32bfin
KALLSYMS += --symbol-prefix=_

KBUILD_DEFCONFIG := BF537-STAMP_defconfig
diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile
index 8ae0d26..6a4807f 100644
--- a/arch/ia64/Makefile
+++ b/arch/ia64/Makefile
@@ -22,7 +22,7 @@ CHECKFLAGS += -m64 -D__ia64=1 -D__ia64__=1 -D_LP64 -D__LP64__

OBJCOPYFLAGS := --strip-all
LDFLAGS_vmlinux := -static
-LDFLAGS_MODULE += -T $(srctree)/arch/ia64/module.lds
+KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/ia64/module.lds
AFLAGS_KERNEL := -mconstant-gp
EXTRA :=

diff --git a/arch/m32r/Makefile b/arch/m32r/Makefile
index 469766b..14a3c23 100644
--- a/arch/m32r/Makefile
+++ b/arch/m32r/Makefile
@@ -13,7 +13,7 @@ LDFLAGS_vmlinux :=

KBUILD_CFLAGS += -pipe -fno-schedule-insns
CFLAGS_KERNEL += -mmodel=medium
-CFLAGS_MODULE += -mmodel=large
+KBUILD_CFLAGS_MODULE += -mmodel=large

ifdef CONFIG_CHIP_VDEC2
cflags-$(CONFIG_ISA_M32R2) += -DNO_FPU -Wa,-bitinst
diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile
index 570d85c..b06a7e3 100644
--- a/arch/m68k/Makefile
+++ b/arch/m68k/Makefile
@@ -18,7 +18,7 @@ KBUILD_DEFCONFIG := multi_defconfig
# override top level makefile
AS += -m68020
LDFLAGS := -m m68kelf
-LDFLAGS_MODULE += -T $(srctree)/arch/m68k/kernel/module.lds
+KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/m68k/kernel/module.lds
ifneq ($(SUBARCH),$(ARCH))
ifeq ($(CROSS_COMPILE),)
CROSS_COMPILE := $(call cc-cross-prefix, \
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 0b9c01a..f7139b2 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -93,7 +93,8 @@ all-$(CONFIG_SYS_SUPPORTS_ZBOOT)+= vmlinuz
cflags-y += -G 0 -mno-abicalls -fno-pic -pipe
cflags-y += -msoft-float
LDFLAGS_vmlinux += -G 0 -static -n -nostdlib
-MODFLAGS += -mlong-calls
+KBUILD_AFLAGS_MODULE += -mlong-calls
+KBUILD_CFLAGS_MODULE += -mlong-calls

cflags-y += -ffreestanding

@@ -185,7 +186,8 @@ cflags-$(CONFIG_CPU_DADDI_WORKAROUNDS) += $(call cc-option,-mno-daddi,)

ifdef CONFIG_CPU_SB1
ifdef CONFIG_SB1_PASS_1_WORKAROUNDS
-MODFLAGS += -msb1-pass1-workarounds
+KBUILD_AFLAGS_MODULE += -msb1-pass1-workarounds
+KBUILD_CFLAGS_MODULE += -msb1-pass1-workarounds
endif
endif

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 77cfe7a..5d42f5e 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -94,7 +94,7 @@ else
endif
endif

-LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
+KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o

ifeq ($(CONFIG_TUNE_CELL),y)
KBUILD_CFLAGS += $(call cc-option,-mtune=cell)
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 30c5f01..0c9e6c6 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -24,7 +24,8 @@ CHECKFLAGS += -D__s390__ -msize-long
else
LD_BFD := elf64-s390
LDFLAGS := -m elf64_s390
-MODFLAGS += -fpic -D__PIC__
+KBUILD_AFLAGS_MODULE += -fpic -D__PIC__
+KBUILD_CFLAGS_MODULE += -fpic -D__PIC__
KBUILD_CFLAGS += -m64
KBUILD_AFLAGS += -m64
UTS_MACHINE := s390x
diff --git a/arch/score/Makefile b/arch/score/Makefile
index 68e0cd0..d77dc63 100644
--- a/arch/score/Makefile
+++ b/arch/score/Makefile
@@ -20,7 +20,8 @@ cflags-y += -G0 -pipe -mel -mnhwloop -D__SCOREEL__ \
#
KBUILD_AFLAGS += $(cflags-y)
KBUILD_CFLAGS += $(cflags-y)
-MODFLAGS += -mlong-calls
+KBUILD_AFLAGS_MODULE += -mlong-calls
+KBUILD_CFLAGS_MODULE += -mlong-calls
LDFLAGS += --oformat elf32-littlescore
LDFLAGS_vmlinux += -G0 -static -nostdlib

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 390aae4..5e7c40e 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -115,7 +115,10 @@ endif
# ---------------------------------------------------------------------------

# Default is built-in, unless we know otherwise
-modkern_cflags = $(if $(part-of-module), $(CFLAGS_MODULE), $(CFLAGS_KERNEL))
+modkern_cflags = \
+ $(if $(part-of-module), \
+ $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
+ $(CFLAGS_KERNEL))
quiet_modtag := $(empty) $(empty)

$(real-objs-m) : part-of-module := y
@@ -250,8 +253,8 @@ $(obj)/%.lst: $(src)/%.c FORCE

modkern_aflags := $(AFLAGS_KERNEL)

-$(real-objs-m) : modkern_aflags := $(AFLAGS_MODULE)
-$(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE)
+$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
+$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)

quiet_cmd_as_s_S = CPP $(quiet_modtag) $@
cmd_as_s_S = $(CPP) $(a_flags) -o $@ $<
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 8f14c81..3e3f024 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -107,7 +107,7 @@ $(modules:.ko=.mod.c): __modpost ;
modname = $(notdir $(@:.mod.o=))

quiet_cmd_cc_o_c = CC $@
- cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE) \
+ cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
-c -o $@ $<

$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
@@ -117,8 +117,9 @@ targets += $(modules:.ko=.mod.o)

# Step 6), final link of the modules
quiet_cmd_ld_ko_o = LD [M] $@
- cmd_ld_ko_o = $(LD) -r $(LDFLAGS) $(LDFLAGS_MODULE) -o $@ \
- $(filter-out FORCE,$^)
+ cmd_ld_ko_o = $(LD) -r $(LDFLAGS) \
+ $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
+ -o $@ $(filter-out FORCE,$^)

$(modules): %.ko :%.o %.mod.o FORCE
$(call if_changed,ld_ko_o)
--
1.6.0.6