From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-x242.google.com (mail-pl0-x242.google.com [IPv6:2607:f8b0:400e:c01::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40wqQy2brrzDr5J for ; Wed, 30 May 2018 22:19:38 +1000 (AEST) Received: by mail-pl0-x242.google.com with SMTP id n10-v6so10991807plp.0 for ; Wed, 30 May 2018 05:19:38 -0700 (PDT) From: Nicholas Piggin To: linux-kbuild@vger.kernel.org Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, Masahiro Yamada , Segher Boessenkool Subject: [PATCH v5 1/4] powerpc/kbuild: set default generic machine type for 32-bit compile Date: Wed, 30 May 2018 22:19:19 +1000 Message-Id: <20180530121922.22122-2-npiggin@gmail.com> In-Reply-To: <20180530121922.22122-1-npiggin@gmail.com> References: <20180530121922.22122-1-npiggin@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Some 64-bit toolchains uses the wrong ISA variant for compiling 32-bit kernels, even with -m32. Debian's powerpc64le is one such case, and that is because it is built with --with-cpu=power8. So when cross compiling a 32-bit kernel with a 64-bit toolchain, set -mcpu=powerpc initially, which is the generic 32-bit powerpc machine type and scheduling model. CPU and platform code can override this with subsequent -mcpu flags if necessary. This is not done for 32-bit toolchains otherwise it would override their defaults, which are presumably set appropriately for the environment (moreso than a 64-bit cross compiler). This fixes a lot of build failures due to incompatible assembly when compiling 32-bit kernel with th Debian powerpc64le 64-bit toolchain. Cc: Segher Boessenkool Signed-off-by: Nicholas Piggin Since v1: reworded changelog to explain the cause of the problem (thanks Segher) and moved the flags into the 64-32 cross compile case. --- arch/powerpc/Makefile | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 95813df90801..d628724087c6 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -24,6 +24,14 @@ ifeq ($(HAS_BIARCH),y) ifeq ($(CROSS32_COMPILE),) CROSS32CC := $(CC) -m32 KBUILD_ARFLAGS += --target=elf32-powerpc +ifdef CONFIG_PPC32 +# These options will be overridden by any -mcpu option that the CPU +# or platform code sets later on the command line, but they are needed +# to set a sane 32-bit cpu target for the 64-bit cross compiler which +# may default to the wrong ISA. +KBUILD_CFLAGS += -mcpu=powerpc +KBUILD_AFLAGS += -mcpu=powerpc +endif endif endif -- 2.17.0