[PATCH 2/3] kbuild: allow assignment to {A,C}FLAGS_KERNEL on the command line

Sam Ravnborg
2010-07-28T18:28:06Z

From 4236ab8d726868df7a28132023e6b31e1d82e5b3 Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@ravnborg.org>
Date: Wed, 28 Jul 2010 19:11:27 +0200
Subject: [PATCH 2/3] kbuild: allow assignment to {A,C}FLAGS_KERNEL on the command line

It is now possible to assign options to AS and CC
on the command line - which is only used for built-in code.

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

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

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

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
---
Documentation/kbuild/kbuild.txt | 10 ++++++++++
Documentation/kbuild/makefiles.txt | 9 +++++++--
Makefile | 4 ++++
arch/ia64/Makefile | 4 ++--
arch/m32r/Makefile | 2 +-
scripts/Makefile.build | 4 ++--
6 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index d9c6554..e903f20 100644
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -28,10 +28,20 @@ AFLAGS_MODULE
--------------------------------------------------
Addtional module specific options to use for $(AS).

+AFLAGS_KERNEL
+--------------------------------------------------
+Addtional options for $(AS) when used for assembler
+code for code that is compiled as built-in.
+
KCFLAGS
--------------------------------------------------
Additional options to the C compiler (for built-in and modules).

+CFLAGS_KERNEL
+--------------------------------------------------
+Addtional options for $(CC) when used to compile
+code that is compiled as built-in.
+
CFLAGS_MODULE
--------------------------------------------------
Addtional module specific options to use for $(CC).
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index 802341a..5c878cc 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -923,9 +923,9 @@ When kbuild executes, the following steps are followed (roughly):
The first example utilises the trick that a config option expands
to 'y' when selected.

- CFLAGS_KERNEL $(CC) options specific for built-in
+ KBUILD_AFLAGS_KERNEL $(AS) options specific for built-in

- $(CFLAGS_KERNEL) contains extra C compiler flags used to compile
+ $(KBUILD_AFLAGS_KERNEL) contains extra C compiler flags used to compile
resident kernel code.

KBUILD_AFLAGS_MODULE Options for $(AS) when building modules
@@ -934,6 +934,11 @@ When kbuild executes, the following steps are followed (roughly):
are used for $(AS).
From commandline AFLAGS_MODULE shall be used (see kbuild.txt).

+ KBUILD_CFLAGS_KERNEL $(CC) options specific for built-in
+
+ $(KBUILD_CFLAGS_KERNEL) contains extra C compiler flags used to compile
+ resident kernel code.
+
KBUILD_CFLAGS_MODULE Options for $(CC) when building modules

$(KBUILD_CFLAGS_MODULE) is used to add arch specific options that
diff --git a/Makefile b/Makefile
index 88447e7..2fb144e 100644
--- a/Makefile
+++ b/Makefile
@@ -353,6 +353,8 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-Werror-implicit-function-declaration \
-Wno-format-security \
-fno-delete-null-pointer-checks
+KBUILD_AFLAGS_KERNEL :=
+KBUILD_CFLAGS_KERNEL :=
KBUILD_AFLAGS := -D__ASSEMBLY__
KBUILD_AFLAGS_MODULE := -DMODULE
KBUILD_CFLAGS_MODULE := -DMODULE
@@ -372,6 +374,7 @@ 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
+export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL

# When compiling out-of-tree modules, put MODVERDIR in the module
# tree rather than in the kernel tree. The kernel tree might
@@ -1483,6 +1486,7 @@ cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
$(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)

a_flags = -Wp,-MD,$(depfile) $(KBUILD_AFLAGS) $(AFLAGS_KERNEL) \
+ $(KBUILD_AFLAGS_KERNEL) \
$(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(KBUILD_CPPFLAGS) \
$(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)

diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile
index 6a4807f..be7bfa1 100644
--- a/arch/ia64/Makefile
+++ b/arch/ia64/Makefile
@@ -23,12 +23,12 @@ CHECKFLAGS += -m64 -D__ia64=1 -D__ia64__=1 -D_LP64 -D__LP64__
OBJCOPYFLAGS := --strip-all
LDFLAGS_vmlinux := -static
KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/ia64/module.lds
-AFLAGS_KERNEL := -mconstant-gp
+KBUILD_AFLAGS_KERNEL := -mconstant-gp
EXTRA :=

cflags-y := -pipe $(EXTRA) -ffixed-r13 -mfixed-range=f12-f15,f32-f127 \
-falign-functions=32 -frename-registers -fno-optimize-sibling-calls
-CFLAGS_KERNEL := -mconstant-gp
+KBUILD_CFLAGS_KERNEL := -mconstant-gp

GAS_STATUS = $(shell $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)")
KBUILD_CPPFLAGS += $(shell $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")
diff --git a/arch/m32r/Makefile b/arch/m32r/Makefile
index 14a3c23..8ff5ba0 100644
--- a/arch/m32r/Makefile
+++ b/arch/m32r/Makefile
@@ -12,7 +12,7 @@ OBJCOPYFLAGS := -O binary -R .note -R .comment -S
LDFLAGS_vmlinux :=

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

ifdef CONFIG_CHIP_VDEC2
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 5e7c40e..a1a5cf9 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -118,7 +118,7 @@ endif
modkern_cflags = \
$(if $(part-of-module), \
$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
- $(CFLAGS_KERNEL))
+ $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
quiet_modtag := $(empty) $(empty)

$(real-objs-m) : part-of-module := y
@@ -251,7 +251,7 @@ $(obj)/%.lst: $(src)/%.c FORCE
# Compile assembler sources (.S)
# ---------------------------------------------------------------------------

-modkern_aflags := $(AFLAGS_KERNEL)
+modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)

$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
--
1.6.0.6