linux/arch/arc/Makefile
Vineet Gupta 20d780374c ARC: build: Better way to detect ISA compatible toolchain
ARC architecture has 2 instruction sets: ARCompact/ARCv2.
While same gcc supports compiling for either (using appropriate toggles),
we can't use the same toolchain to build kernel because libgcc needs
to be unique and the toolchian (uClibc based) is not multilibed.

uClibc toolchain is convenient since it allows all userspace and
kernel to be built with a single install for an ISA.

This however means 2 gnu installs (with same triplet prefix) are needed
for building for 2 ISA and need to be in PATH.
As developers we keep switching the builds, but would occassionally fail
to update the PATH leading to usage of wrong tools. And this would only
show up at the end of kernel build when linking incompatible libgcc.

So the initial solution was to have gcc define a special preprocessor macro
DEFAULT_CPU_xxx which is unique for default toolchain configuration.
Claudiu proposed using grep for an existing preprocessor macro which is
again uniquely defined per ISA.

Cc: Michal Marek <mmarek@suse.cz>
Suggested-by: Claudiu Zissulescu <claziss@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-03-12 11:58:30 +05:30

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Makefile

#
# Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
UTS_MACHINE := arc
ifeq ($(CROSS_COMPILE),)
ifndef CONFIG_CPU_BIG_ENDIAN
CROSS_COMPILE := arc-linux-
else
CROSS_COMPILE := arceb-linux-
endif
endif
KBUILD_DEFCONFIG := nsim_700_defconfig
cflags-y += -fno-common -pipe -fno-builtin -D__linux__
cflags-$(CONFIG_ISA_ARCOMPACT) += -mA7
cflags-$(CONFIG_ISA_ARCV2) += -mcpu=archs
is_700 = $(shell $(CC) -dM -E - < /dev/null | grep -q "ARC700" && echo 1 || echo 0)
ifdef CONFIG_ISA_ARCOMPACT
ifeq ($(is_700), 0)
$(error Toolchain not configured for ARCompact builds)
endif
endif
ifdef CONFIG_ISA_ARCV2
ifeq ($(is_700), 1)
$(error Toolchain not configured for ARCv2 builds)
endif
endif
ifdef CONFIG_ARC_CURR_IN_REG
# For a global register defintion, make sure it gets passed to every file
# We had a customer reported bug where some code built in kernel was NOT using
# any kernel headers, and missing the r25 global register
# Can't do unconditionally because of recursive include issues
# due to <linux/thread_info.h>
LINUXINCLUDE += -include ${src}/arch/arc/include/asm/current.h
endif
upto_gcc44 := $(call cc-ifversion, -le, 0404, y)
atleast_gcc44 := $(call cc-ifversion, -ge, 0404, y)
atleast_gcc48 := $(call cc-ifversion, -ge, 0408, y)
cflags-$(atleast_gcc44) += -fsection-anchors
cflags-$(CONFIG_ARC_HAS_LLSC) += -mlock
cflags-$(CONFIG_ARC_HAS_SWAPE) += -mswape
ifdef CONFIG_ISA_ARCV2
ifndef CONFIG_ARC_HAS_LL64
cflags-y += -mno-ll64
endif
ifndef CONFIG_ARC_HAS_DIV_REM
cflags-y += -mno-div-rem
endif
endif
cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables
# By default gcc 4.8 generates dwarf4 which kernel unwinder can't grok
ifeq ($(atleast_gcc48),y)
cflags-$(CONFIG_ARC_DW2_UNWIND) += -gdwarf-2
endif
ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
# Generic build system uses -O2, we want -O3
# Note: No need to add to cflags-y as that happens anyways
ARCH_CFLAGS += -O3
endif
# small data is default for elf32 tool-chain. If not usable, disable it
# This also allows repurposing GP as scratch reg to gcc reg allocator
disable_small_data := y
cflags-$(disable_small_data) += -mno-sdata -fcall-used-gp
cflags-$(CONFIG_CPU_BIG_ENDIAN) += -mbig-endian
ldflags-$(CONFIG_CPU_BIG_ENDIAN) += -EB
# STAR 9000518362: (fixed with binutils shipping with gcc 4.8)
# arc-linux-uclibc-ld (buildroot) or arceb-elf32-ld (EZChip) don't accept
# --build-id w/o "-marclinux". Default arc-elf32-ld is OK
ldflags-$(upto_gcc44) += -marclinux
LIBGCC := $(shell $(CC) $(cflags-y) --print-libgcc-file-name)
# Modules with short calls might break for calls into builtin-kernel
KBUILD_CFLAGS_MODULE += -mlong-calls -mno-millicode
# Finally dump eveything into kernel build system
KBUILD_CFLAGS += $(cflags-y)
KBUILD_AFLAGS += $(KBUILD_CFLAGS)
LDFLAGS += $(ldflags-y)
head-y := arch/arc/kernel/head.o
# See arch/arc/Kbuild for content of core part of the kernel
core-y += arch/arc/
# w/o this dtb won't embed into kernel binary
core-y += arch/arc/boot/dts/
core-$(CONFIG_ARC_PLAT_SIM) += arch/arc/plat-sim/
core-$(CONFIG_ARC_PLAT_TB10X) += arch/arc/plat-tb10x/
core-$(CONFIG_ARC_PLAT_AXS10X) += arch/arc/plat-axs10x/
drivers-$(CONFIG_OPROFILE) += arch/arc/oprofile/
libs-y += arch/arc/lib/ $(LIBGCC)
boot := arch/arc/boot
#default target for make without any arguements.
KBUILD_IMAGE := bootpImage
all: $(KBUILD_IMAGE)
bootpImage: vmlinux
boot_targets += uImage uImage.bin uImage.gz
$(boot_targets): vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
%.dtb %.dtb.S %.dtb.o: scripts
$(Q)$(MAKE) $(build)=$(boot)/dts $(boot)/dts/$@
dtbs: scripts
$(Q)$(MAKE) $(build)=$(boot)/dts
archclean:
$(Q)$(MAKE) $(clean)=$(boot)
# Hacks to enable final link due to absence of link-time branch relexation
# and gcc choosing optimal(shorter) branches at -O3
#
# vineetg Feb 2010: -mlong-calls switched off for overall kernel build
# However lib/decompress_inflate.o (.init.text) calls
# zlib_inflate_workspacesize (.text) causing relocation errors.
# Thus forcing all exten calls in this file to be long calls
export CFLAGS_decompress_inflate.o = -mmedium-calls
export CFLAGS_initramfs.o = -mmedium-calls
ifdef CONFIG_SMP
export CFLAGS_core.o = -mmedium-calls
endif