[PATCH] [0/5] kbuild: A couple of Kbuild fixes/improvements

[PATCH] [0/5] kbuild: A couple of Kbuild fixes/improvements

[Andi Kleen]

Some build system patches that accumulated in my tree:

- Fix mcount handling
- Fix gold linker support
- Add some gcc 4.5 support

One will address the problem Dave A. reported earlier today.

-Andi

[PATCH] [1/5] kbuild: Fix ld-option Makefile macro to really work

[Andi Kleen]

Needed for the next patch

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 scripts/Kbuild.include |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux-2.6.31-rc1-ak/scripts/Kbuild.include
===================================================================
--- linux-2.6.31-rc1-ak.orig/scripts/Kbuild.include
+++ linux-2.6.31-rc1-ak/scripts/Kbuild.include
@@ -83,11 +83,12 @@ TMPOUT := $(if $(KBUILD_EXTMOD),$(firstw
 # is automatically cleaned up.
 try-run = $(shell set -e;		\
 	TMP="$(TMPOUT).$$$$.tmp";	\
+	TMPO="$(TMPOUT).$$$$.o";	\
 	if ($(1)) >/dev/null 2>&1;	\
 	then echo "$(2)";		\
 	else echo "$(3)";		\
 	fi;				\
-	rm -f "$$TMP")
+	rm -f "$$TMP" "$$TMPO")
 
 # as-option
 # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
@@ -133,7 +134,7 @@ cc-ifversion = $(shell [ $(call cc-versi
 # ld-option
 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
 ld-option = $(call try-run,\
-	$(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
+	$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
 
 ######
 

[PATCH] [2/5] kbuild: Check if linker supports the -X option

[Andi Kleen]

The new alternative `gold' linker in recent binutils doesn't support
the -X option. This breaks allyesconfig builds that have 
CONFIG_STRIP_ASM_SYMS enabled. Check if the linker really supports
the option using ld-option.

This requires fixes in earlier patches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 Makefile |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.31-rc1-ak/Makefile
===================================================================
--- linux-2.6.31-rc1-ak.orig/Makefile
+++ linux-2.6.31-rc1-ak/Makefile
@@ -599,7 +599,7 @@ LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
 LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)
 
 ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
-LDFLAGS_vmlinux	+= -X
+LDFLAGS_vmlinux	+= $(call ld-option, -X,)
 endif
 
 # Default kernel image to build when no specific target is given.

[PATCH] [3/5] kbuild: Echo the record_mcount command

[Andi Kleen]

I had some problems with record_mcount in the Makefile and it was hard
to track down. Echo it by default to make it easier to diagnose.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 scripts/Makefile.build |    1 +
 1 file changed, 1 insertion(+)

Index: linux-2.6.31-rc1-ak/scripts/Makefile.build
===================================================================
--- linux-2.6.31-rc1-ak.orig/scripts/Makefile.build
+++ linux-2.6.31-rc1-ak/scripts/Makefile.build
@@ -216,6 +216,7 @@ define rule_cc_o_c
 	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
 	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
 	$(cmd_modversions)						  \
+	$(call echo-cmd,record_mcount)					  \
 	$(cmd_record_mcount)						  \
 	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
 	                                              $(dot-target).tmp;  \

[PATCH] [4/5] kbuild: Fail build if recordmcount.pl fails

[Andi Kleen]

When this script fails the build should fail too. Otherwise there
are mysterious build failures later.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 scripts/Makefile.build |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.31-rc1-ak/scripts/Makefile.build
===================================================================
--- linux-2.6.31-rc1-ak.orig/scripts/Makefile.build
+++ linux-2.6.31-rc1-ak/scripts/Makefile.build
@@ -206,7 +206,7 @@ cmd_modversions =							\
 endif
 
 ifdef CONFIG_FTRACE_MCOUNT_RECORD
-cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
+cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 	"$(if $(CONFIG_64BIT),64,32)" \
 	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC)" "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 	"$(if $(part-of-module),1,0)" "$(@)";

[PATCH] [5/5] kbuild: Set -fconserve-stack option for gcc 4.5

[Andi Kleen]

The upcomming gcc 4.5 has a new -fconserve-stack option 
that tells the inliner to take stack frame size in account.
Set it if the compiler supports it.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 Makefile |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-2.6.31-rc3-ak/Makefile
===================================================================
--- linux-2.6.31-rc3-ak.orig/Makefile
+++ linux-2.6.31-rc3-ak/Makefile
@@ -575,6 +575,9 @@ KBUILD_CFLAGS	+= $(call cc-option,-fno-s
 # revert to pre-gcc-4.4 behaviour of .eh_frame
 KBUILD_CFLAGS	+= $(call cc-option,-fno-dwarf2-cfi-asm)
 
+# conserve stack if available
+KBUILD_CFLAGS   += $(call cc-option,-fconserve-stack)
+
 # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
 # But warn user when we do so
 warn-assign = \

Re: [PATCH] [1/5] kbuild: Fix ld-option Makefile macro to really work

[Sam Ravnborg]

On Tue, Sep 15, 2009 at 03:01:47PM +0200, Andi Kleen wrote:
> > So now we pass the option direct to the linker rather than via gcc -wl.
> > I assume this breaks the other 8 uses of ld-option in the kernel?
> > 
> > Or does ld understand the -wl,... syntax?
> 
> It does not. But -X is passed directly to the linker, not via gcc,
> so it needs to probe ld directly
> 
> The right fix is probably an new macro that works with ld (and
> ideally rename this one which is confusingly named) I'll
> send an updated patch.
Thanks.
Please do remember to update the documentation
in Documentation/kbuild/makefiles.txt.

	Sam

Re: [PATCH] [1/5] kbuild: Fix ld-option Makefile macro to really work

[Andi Kleen]

> So now we pass the option direct to the linker rather than via gcc -wl.
> I assume this breaks the other 8 uses of ld-option in the kernel?
> 
> Or does ld understand the -wl,... syntax?

It does not. But -X is passed directly to the linker, not via gcc,
so it needs to probe ld directly

The right fix is probably an new macro that works with ld (and
ideally rename this one which is confusingly named) I'll
send an updated patch.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

Re: [PATCH] [1/5] kbuild: Fix ld-option Makefile macro to really work

[Sam Ravnborg]

On Mon, Sep 14, 2009 at 10:18:06PM +0200, Andi Kleen wrote:
> 
> Needed for the next patch
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> 
> ---
>  scripts/Kbuild.include |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> Index: linux-2.6.31-rc1-ak/scripts/Kbuild.include
> ===================================================================
> --- linux-2.6.31-rc1-ak.orig/scripts/Kbuild.include
> +++ linux-2.6.31-rc1-ak/scripts/Kbuild.include
> @@ -83,11 +83,12 @@ TMPOUT := $(if $(KBUILD_EXTMOD),$(firstw
>  # is automatically cleaned up.
>  try-run = $(shell set -e;		\
>  	TMP="$(TMPOUT).$$$$.tmp";	\
> +	TMPO="$(TMPOUT).$$$$.o";	\
>  	if ($(1)) >/dev/null 2>&1;	\
>  	then echo "$(2)";		\
>  	else echo "$(3)";		\
>  	fi;				\
> -	rm -f "$$TMP")
> +	rm -f "$$TMP" "$$TMPO")
>  
>  # as-option
>  # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
> @@ -133,7 +134,7 @@ cc-ifversion = $(shell [ $(call cc-versi
>  # ld-option
>  # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
>  ld-option = $(call try-run,\
> -	$(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
> +	$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
>  
>  ######

So now we pass the option direct to the linker rather than via gcc -wl.
I assume this breaks the other 8 uses of ld-option in the kernel?

Or does ld understand the -wl,... syntax?

	Sam

[PATCH] [1/5] kbuild: Fix ld-option Makefile macro to really work

[Andi Kleen]

Needed for the next patch

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 scripts/Kbuild.include |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux-2.6.31-rc1-ak/scripts/Kbuild.include
===================================================================
--- linux-2.6.31-rc1-ak.orig/scripts/Kbuild.include
+++ linux-2.6.31-rc1-ak/scripts/Kbuild.include
@@ -83,11 +83,12 @@ TMPOUT := $(if $(KBUILD_EXTMOD),$(firstw
 # is automatically cleaned up.
 try-run = $(shell set -e;		\
 	TMP="$(TMPOUT).$$$$.tmp";	\
+	TMPO="$(TMPOUT).$$$$.o";	\
 	if ($(1)) >/dev/null 2>&1;	\
 	then echo "$(2)";		\
 	else echo "$(3)";		\
 	fi;				\
-	rm -f "$$TMP")
+	rm -f "$$TMP" "$$TMPO")
 
 # as-option
 # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
@@ -133,7 +134,7 @@ cc-ifversion = $(shell [ $(call cc-versi
 # ld-option
 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
 ld-option = $(call try-run,\
-	$(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
+	$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
 
 ######