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SubjectRe: [PATCH/RFC] Re: linux-next: build failure after merge of the luto-misc tree
On Fri, Jul 22, 2016 at 11:37:39AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Jul 21, 2016 at 10:41:18PM -0500, Josh Poimboeuf escreveu:
> > On Fri, Jul 22, 2016 at 09:23:02AM +1000, Stephen Rothwell wrote:
> > > It just looks like objtool was not written with cross compilation in
> > > mind?
>
> > I don't know yet what the specific problem is, but objtool should work
> > fine in a cross-compiled environment. It needs to be compiled with the
> > host (powerpc) compiler, but then it needs to disassemble target (x86)
> > files. It worked fine before the bitsperlong.h files were merged.
>
> So, trying to summarize from the various messages in this thread:
>
> In Tue, Jul 19, 2016 at 01:26:08PM +1000, Stephen Rothwell wrote:
>
> > It produces these errors (from the x86_64 allmodconfig build):
> >
> > In file included from
> > /home/sfr/next/next/tools/arch/x86/include/uapi/asm/bitsperlong.h:10:0,
> > from /usr/include/asm-generic/int-ll64.h:11,
> > from /usr/include/powerpc64le-linux-gnu/asm/types.h:27,
> > from /home/sfr/next/next/tools/include/linux/types.h:9,
> > from /home/sfr/next/next/tools/include/linux/list.h:4,
> > from elf.h:23,
> > from elf.c:30:
> > /home/sfr/next/next/tools/include/asm-generic/bitsperlong.h:13:2:
> > error: #error Inconsistent word size. Check asm/bitsperlong.h
> > #error Inconsistent word size. Check asm/bitsperlong.h
> > ^
>
> So it starts at tools/arch/x86/include/uapi/asm/bitsperlong.h, and as
> you mention, this should've instead be using the host headers, i.e.:
>
> tools/arch/powerpc/include/uapi/asm/bitsperlong.h
>
> Which it will if it uses HOSTARCH in tools/objtool/Makefile when setting
> up the header search path, I have two csets in my perf/core branch that
> fixes this, and that are equivalent to the last patch Stephen tried:
>
> $ git log --oneline -2
> 87f7dc54366a objtool: Use tools/scripts/Makefile.arch to get ARCH and HOSTARCH
> 0eec6770ab60 tools build: Add HOSTARCH Makefile variable
> $
>
> Ok, so now it uses the right file, see the whole sequence at the end of this
> e-mail, but it boils down to:
>
> -----------------------------------------------------------------------------
> #if defined(__powerpc64__)
> # define __BITS_PER_LONG 64
> #else
> # define __BITS_PER_LONG 32
> #endif
>
> #ifdef __SIZEOF_LONG__
> #define BITS_PER_LONG (__CHAR_BIT__ * __SIZEOF_LONG__)
> #else
> #define BITS_PER_LONG __WORDSIZE
> #endif
>
> #if BITS_PER_LONG != __BITS_PER_LONG
> #error Inconsistent word size. Check asm/bitsperlong.h
> #endif
> -----------------------------------------------------------------------------
>
> Which I think has no problems, right? The last problem reported ty Stephen now is:
>
> In Fri, 22 Jul 2016 09:23:02 +1000, Stephen Rothwell wrote:
>
> > That gets me this errors from the x86_64 allmodconfig build:
>
> > tools/objtool/objtool-in.o: In function `decode_instructions':
> > tools/objtool/builtin-check.c:276: undefined reference to `arch_decode_instruction'
>
> Should work, since ARCH should be x86 and then tools/objtool/Build will have
> this:
>
> objtool-y += arch/$(ARCH)/
>
> Turned into:
>
> objtool-y += arch/x86/
>
> Which will build tools/objtool/arch/x86/decode.c, that will provide that
> arch_decode_instruction() function :-\
>
> I.e. with the two patches I mentioned, that are equivalent to the last patch I
> sent to Stephen for testing, we would end up with HOSTARCH=powerpc and
> ARCH=x86, no?

Thanks for spelling it out, that helped a lot.

I'm guessing Stephen is setting ARCH=x86_64 on the command-line rather
than ARCH=x86. How about the following patch? Stephen, can you confirm
this fixes it? This is on top of Arnaldo's other two fixes here:

https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git perf/core

From: Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH] tools build: fix objtool build with ARCH=x86_64

The objtool build fails in a cross-compiled environment on a non-x86
host with "ARCH=x86_64":

tools/objtool/objtool-in.o: In function `decode_instructions':
tools/objtool/builtin-check.c:276: undefined reference to `arch_decode_instruction'

We could override the ARCH environment variable and change it back to
x86, similar to what the objtool Makefile was doing before; but it's
tricky to override environment variables consistently.

Instead, take a similar approach used by the Linux top-level Makefile
and introduce a SRCARCH Makefile variable which evaluates to "x86" when
ARCH is either "x86_64" or "x86".

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
tools/objtool/Build | 2 +-
tools/objtool/Makefile | 2 +-
tools/scripts/Makefile.arch | 32 ++++++++++++++++++++++++++++++++
3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/Build b/tools/objtool/Build
index 2457916..d6cdece 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -1,4 +1,4 @@
-objtool-y += arch/$(ARCH)/
+objtool-y += arch/$(SRCARCH)/
objtool-y += builtin-check.o
objtool-y += elf.o
objtool-y += special.o
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index c9ad80a..577f2d4 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -29,7 +29,7 @@ elfshdr := $(shell echo '\#include <libelf.h>' | $(CC) $(CFLAGS) -x c -E - | gre
CFLAGS += $(if $(elfshdr),,-DLIBELF_USE_DEPRECATED)

AWK = awk
-export srctree OUTPUT CFLAGS ARCH AWK
+export srctree OUTPUT CFLAGS SRCARCH AWK
include $(srctree)/tools/build/Makefile.include

$(OBJTOOL_IN): fixdep FORCE
diff --git a/tools/scripts/Makefile.arch b/tools/scripts/Makefile.arch
index 887321c..ad85b92 100644
--- a/tools/scripts/Makefile.arch
+++ b/tools/scripts/Makefile.arch
@@ -5,10 +5,42 @@ HOSTARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \
-e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
-e s/sh[234].*/sh/ -e s/aarch64.*/arm64/ \
-e s/tile.*/tile/ )
+
ifndef ARCH
ARCH := $(HOSTARCH)
endif

+SRCARCH := $(ARCH)
+
+# Additional ARCH settings for x86
+ifeq ($(ARCH),i386)
+ SRCARCH := x86
+endif
+ifeq ($(ARCH),x86_64)
+ SRCARCH := x86
+endif
+
+# Additional ARCH settings for sparc
+ifeq ($(ARCH),sparc32)
+ SRCARCH := sparc
+endif
+ifeq ($(ARCH),sparc64)
+ SRCARCH := sparc
+endif
+
+# Additional ARCH settings for sh
+ifeq ($(ARCH),sh64)
+ SRCARCH := sh
+endif
+
+# Additional ARCH settings for tile
+ifeq ($(ARCH),tilepro)
+ SRCARCH := tile
+endif
+ifeq ($(ARCH),tilegx)
+ SRCARCH := tile
+endif
+
LP64 := $(shell echo __LP64__ | ${CC} ${CFLAGS} -E -x c - | tail -n 1)
ifeq ($(LP64), 1)
IS_64_BIT := 1
\
 
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