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linux/arch/arc/Makefile
Vineet Gupta cfca4b5abe ARC: entry: use gp to cache task pointer (vs. r25)
The motivation is eventual ABI considerations for ARCv3 but even without
it this change us worthwhile as diffstat reduces 100 net lines

r25 is a callee saved register, normally not saved by entry code in
pt_regs. However because of its usage in CONFIG_ARC_CURR_IN_REG it needs
to be. This in turn requires a whole bunch of special casing when we
need to access r25. Then there is distinction between user mode r25 vs.
kernel mode r25 - hence distinct SAVE_CALLEE_SAVED_{USER,KERNEL}

Instead use gp which is a scratch register and thus saved already in entry
code. This cleans things up significantly and much nocer on eyes:

 - SAVE_CALLEE_SAVED_{USER,KERNEL} are now exactly same
 - no special user_r25 slot in pt_reggs

Note that typical global asm registers are callee-saved (r25), but gp is
not callee-saved thus needs additional -ffixed-<reg> toggle

Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2023-08-17 20:31:59 -07:00

113 lines
3.2 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0-only
#
# Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
#
KBUILD_DEFCONFIG := haps_hs_smp_defconfig
ifeq ($(CROSS_COMPILE),)
CROSS_COMPILE := $(call cc-cross-prefix, arc-linux- arceb-linux-)
endif
cflags-y += -fno-common -pipe -fno-builtin -mmedium-calls -D__linux__
tune-mcpu-def-$(CONFIG_ISA_ARCOMPACT) := -mcpu=arc700
tune-mcpu-def-$(CONFIG_ISA_ARCV2) := -mcpu=hs38
ifeq ($(CONFIG_ARC_TUNE_MCPU),)
cflags-y += $(tune-mcpu-def-y)
else
tune-mcpu := $(CONFIG_ARC_TUNE_MCPU)
ifneq ($(call cc-option,$(tune-mcpu)),)
cflags-y += $(tune-mcpu)
else
# The flag provided by 'CONFIG_ARC_TUNE_MCPU' option isn't known by this compiler
# (probably the compiler is too old). Use ISA default mcpu flag instead as a safe option.
$(warning ** WARNING ** CONFIG_ARC_TUNE_MCPU flag '$(tune-mcpu)' is unknown, fallback to '$(tune-mcpu-def-y)')
cflags-y += $(tune-mcpu-def-y)
endif
endif
ifdef CONFIG_ARC_CURR_IN_REG
# For a global register definition, 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 global register
# Can't do unconditionally because of recursive include issues
# due to <linux/thread_info.h>
LINUXINCLUDE += -include $(srctree)/arch/arc/include/asm/current.h
cflags-y += -ffixed-gp
endif
cflags-y += -fsection-anchors
cflags-$(CONFIG_ARC_HAS_LLSC) += -mlock
cflags-$(CONFIG_ARC_HAS_SWAPE) += -mswape
ifdef CONFIG_ISA_ARCV2
ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS
cflags-y += -munaligned-access
else
cflags-y += -mno-unaligned-access
endif
ifndef CONFIG_ARC_HAS_LL64
cflags-y += -mno-ll64
endif
ifndef CONFIG_ARC_HAS_DIV_REM
cflags-y += -mno-div-rem
endif
endif
cfi := $(call as-instr,.cfi_startproc\n.cfi_endproc,-DARC_DW2_UNWIND_AS_CFI)
cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables $(cfi)
# small data is default for elf32 tool-chain. If not usable, disable it
# This also allows repurposing GP as scratch reg to gcc reg allocator
disable_small_data := y
cflags-$(disable_small_data) += -mno-sdata
cflags-$(CONFIG_CPU_BIG_ENDIAN) += -mbig-endian
ldflags-$(CONFIG_CPU_BIG_ENDIAN) += -EB
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)
KBUILD_LDFLAGS += $(ldflags-y)
# w/o this dtb won't embed into kernel binary
core-y += arch/arc/boot/dts/
core-y += arch/arc/plat-sim/
core-$(CONFIG_ARC_PLAT_TB10X) += arch/arc/plat-tb10x/
core-$(CONFIG_ARC_PLAT_AXS10X) += arch/arc/plat-axs10x/
core-$(CONFIG_ARC_SOC_HSDK) += arch/arc/plat-hsdk/
libs-y += arch/arc/lib/ $(LIBGCC)
boot := arch/arc/boot
boot_targets := uImage.bin uImage.gz uImage.lzma
PHONY += $(boot_targets)
$(boot_targets): vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
uimage-default-y := uImage.bin
uimage-default-$(CONFIG_KERNEL_GZIP) := uImage.gz
uimage-default-$(CONFIG_KERNEL_LZMA) := uImage.lzma
PHONY += uImage
uImage: $(uimage-default-y)
@ln -sf $< $(boot)/uImage
@$(kecho) ' Image $(boot)/uImage is ready'
CLEAN_FILES += $(boot)/uImage