From 8a2fd5f3ab6535035f08d7d0fda90abe73c6d282 Mon Sep 17 00:00:00 2001 From: Paul Mundt <lethal@linux-sh.org> Date: Tue, 28 Oct 2008 17:19:35 +0900 Subject: sh: Fix FPU tuning on toolchains with mismatched multilib targets. Presently there is very little standing in the way of using an SH-4 toolchain for building an SH-2 kernel, and vice versa. Binutils itself has no limitations whatsoever and supports explicit ISA hinting, which we already use with varying degrees of success today. This leaves GCC as the odd one out, due to a rather dubious policy decision by the GCC folks to not include all of the CPU family variants in the default list of multilib targets in GCC4. Despite best efforts to the contrary, libgcc itself already contains awareness of the various CPU types and remains generally usable, allowing it to safely be referenced even on a mismatched target (and indeed, explicit ISA tuning by binutils keeps us honest in terms of ensuring that we do not link incompatible objects in). In order to support this, a couple of changes had to be made. Firstly, the introduction of MAYBE_DECLARE_EXPORT(), which provides a __weak extern reference for libgcc resident routines when finer-grained -m<cpu-family> based tuning is not supported by the toolchain. This fixes up the __sdivsi3_i4i and __udivsi3_i4i references when dealing with SH-2 kernels linked with an SH-4 libgcc. Secondly, in case where we are unable to find a suitable match for CPU family tuning but still have a toolchain that defaults to FP instruction generation, a suitable nofpu target must be selected. This is accomplished by selecting the first nofpu multilib target supported by the toolchain, which is also necessary for selecting the proper libgcc to link against. Signed-off-by: Paul Mundt <lethal@linux-sh.org> --- arch/sh/Makefile | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'arch/sh/Makefile') diff --git a/arch/sh/Makefile b/arch/sh/Makefile index 1f409bf..3b2d8e2 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -38,6 +38,22 @@ cflags-$(CONFIG_CPU_SH4A) += $(call cc-option,-m4a,) \ $(call cc-option,-m4a-nofpu,) cflags-$(CONFIG_CPU_SH5) := $(call cc-option,-m5-32media-nofpu,) +ifeq ($(cflags-y),) +# +# In the case where we are stuck with a compiler that has been uselessly +# restricted to a particular ISA, a favourite default of newer GCCs when +# extensive multilib targets are not provided, ensure we get the best fit +# regarding FP generation. This is necessary to avoid references to FP +# variants in libgcc where integer variants exist, which otherwise result +# in link errors. This is intentionally stupid (albeit many orders of +# magnitude less than GCC's default behaviour), as anything with a large +# number of multilib targets better have been built correctly for +# the target in mind. +# +cflags-y += $(shell $(CC) $(KBUILD_CFLAGS) -print-multi-lib | \ + grep nofpu | sed q | sed -e 's/^/-/;s/;.*$$//') +endif + cflags-$(CONFIG_CPU_BIG_ENDIAN) += -mb cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -ml -- cgit v1.1 From 1a30603233fdd104aba430fd8f3443160474b6bb Mon Sep 17 00:00:00 2001 From: Paul Mundt <lethal@linux-sh.org> Date: Tue, 28 Oct 2008 18:50:00 +0900 Subject: sh: sh7785lcr: Select uImage as default image target. Signed-off-by: Paul Mundt <lethal@linux-sh.org> --- arch/sh/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/sh/Makefile') diff --git a/arch/sh/Makefile b/arch/sh/Makefile index 3b2d8e2..240ad6b 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -81,7 +81,8 @@ OBJCOPYFLAGS := -O binary -R .note -R .note.gnu.build-id -R .comment \ -R .stab -R .stabstr -S # Give the various platforms the opportunity to set default image types -defaultimage-$(CONFIG_SUPERH32) := zImage +defaultimage-$(CONFIG_SUPERH32) := zImage +defaultimage-$(CONFIG_SH_SH7785LCR) := uImage # Set some sensible Kbuild defaults KBUILD_DEFCONFIG := shx3_defconfig -- cgit v1.1 From b2d86a3fd9855380598c0c039e712a20086e119f Mon Sep 17 00:00:00 2001 From: Paul Mundt <lethal@linux-sh.org> Date: Tue, 28 Oct 2008 19:37:05 +0900 Subject: sh: Simplify and lock down the ISA tuning. The ISA tuning as it is today can not cope with all of the different variations that are possible, so all we can do is a best attempt based on the CPU family. The DSP and FPU generation are already at odds with each other, and the nommu tuning we weren't handling at all. Additionally, for platforms that never had an FPU, the -nofpu variant never existed, meaning that we would lose out on family granular tuning completely in certain cases. With tat out of the way, we were also using -up versions, allowing for later instructions that branched off of a particular subset of the ISA, but are not actually reflected on the hardware being targetted. This leads to some confusion, and the possibility of bogus instructions on older parts. Kill that off and lock it down to the family being built for specifically. Signed-off-by: Paul Mundt <lethal@linux-sh.org> --- arch/sh/Makefile | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'arch/sh/Makefile') diff --git a/arch/sh/Makefile b/arch/sh/Makefile index 240ad6b..3a74ed6 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -2,7 +2,7 @@ # arch/sh/Makefile # # Copyright (C) 1999 Kaz Kojima -# Copyright (C) 2002, 2003, 2004 Paul Mundt +# Copyright (C) 2002 - 2008 Paul Mundt # Copyright (C) 2002 M. R. Brown # # This file is subject to the terms and conditions of the GNU General Public @@ -20,14 +20,6 @@ isa-$(CONFIG_CPU_SH4AL_DSP) := sh4al isa-$(CONFIG_CPU_SH5) := shmedia isa-$(CONFIG_SH_DSP) := $(isa-y)-dsp -ifndef CONFIG_SH_DSP -ifndef CONFIG_SH_FPU -isa-y := $(isa-y)-nofpu -endif -endif - -isa-y := $(isa-y)-up - cflags-$(CONFIG_CPU_SH2) := $(call cc-option,-m2,) cflags-$(CONFIG_CPU_SH2A) += $(call cc-option,-m2a,) \ $(call cc-option,-m2a-nofpu,) -- cgit v1.1 From ddb72b02414228844ad46f7cbd42eccea01fb485 Mon Sep 17 00:00:00 2001 From: Paul Mundt <lethal@linux-sh.org> Date: Fri, 31 Oct 2008 15:58:53 +0900 Subject: sh: SHmedia ISA tuning fixups. SH-5 doesn't support any elaborate ISA inheritance schemes (-dsp, -up, etc.), so only bother with that if we are building an sh32 kernel. Signed-off-by: Paul Mundt <lethal@linux-sh.org> --- arch/sh/Makefile | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/sh/Makefile') diff --git a/arch/sh/Makefile b/arch/sh/Makefile index 3a74ed6..c43eb0d 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -18,7 +18,11 @@ isa-$(CONFIG_CPU_SH4) := sh4 isa-$(CONFIG_CPU_SH4A) := sh4a isa-$(CONFIG_CPU_SH4AL_DSP) := sh4al isa-$(CONFIG_CPU_SH5) := shmedia + +ifeq ($(CONFIG_SUPERH32),y) isa-$(CONFIG_SH_DSP) := $(isa-y)-dsp +isa-y := $(isa-y)-up +endif cflags-$(CONFIG_CPU_SH2) := $(call cc-option,-m2,) cflags-$(CONFIG_CPU_SH2A) += $(call cc-option,-m2a,) \ -- cgit v1.1