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kernel-ark/arch/m68k/Makefile
Finn Thain 28713169d8 m68k: Add -ffreestanding to CFLAGS 
This patch fixes a build failure when using GCC 8.1:

/usr/bin/ld: block/partitions/ldm.o: in function `ldm_parse_tocblock':
block/partitions/ldm.c:153: undefined reference to `strcmp'

This is caused by a new optimization which effectively replaces a
strncmp() call with a strcmp() call. This affects a number of strncmp()
call sites in the kernel.

The entire class of optimizations is avoided with -fno-builtin, which
gets enabled by -ffreestanding. This may avoid possible future build
failures in case new optimizations appear in future compilers.

I haven't done any performance measurements with this patch but I did
count the function calls in a defconfig build. For example, there are now
23 more sprintf() calls and 39 fewer strcpy() calls. The effect on the
other libc functions is smaller.

If this harms performance we can tackle that regression by optimizing
the call sites, ideally using semantic patches. That way, clang and ICC
builds might benfit too.

Cc: stable@vger.kernel.org
Reference: https://marc.info/?l=linux-m68k&m=154514816222244&w=2
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2019-01-21 10:36:53 +01:00

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Makefile
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#
# m68k/Makefile
#
# This file is included by the global makefile so that you can add your own
# architecture-specific flags and dependencies. Remember to do have actions
# for "archclean" and "archdep" for cleaning up and making dependencies for
# this architecture
#
# This file is subject to the terms and conditions of the GNU General Public
# License. See the file "COPYING" in the main directory of this archive
# for more details.
#
# Copyright (C) 1994 by Hamish Macdonald
# Copyright (C) 2002,2011 Greg Ungerer <gerg@snapgear.com>
#
KBUILD_DEFCONFIG := multi_defconfig
ifneq ($(SUBARCH),$(ARCH))
ifeq ($(CROSS_COMPILE),)
CROSS_COMPILE := $(call cc-cross-prefix, \
m68k-linux-gnu- m68k-linux- m68k-unknown-linux-gnu-)
endif
endif
#
# Enable processor type. Ordering of these is important - we want to
# use the minimum processor type of the range we support. The logic
# for 680x0 will only allow use of the -m68060 or -m68040 if no other
# 680x0 type is specified - and no option is specified for 68030 or
# 68020. The other m68k/ColdFire types always specify some type of
# compiler cpu type flag.
#
ifndef CONFIG_M68040
cpuflags-$(CONFIG_M68060) := -m68060
endif
ifndef CONFIG_M68060
cpuflags-$(CONFIG_M68040) := -m68040
endif
cpuflags-$(CONFIG_M68030) :=
cpuflags-$(CONFIG_M68020) :=
cpuflags-$(CONFIG_M68000) := -m68000
cpuflags-$(CONFIG_M5441x) := $(call cc-option,-mcpu=54455,-mcfv4e)
cpuflags-$(CONFIG_M54xx) := $(call cc-option,-mcpu=5475,-m5200)
cpuflags-$(CONFIG_M5407) := $(call cc-option,-mcpu=5407,-m5200)
cpuflags-$(CONFIG_M532x) := $(call cc-option,-mcpu=532x,-m5307)
cpuflags-$(CONFIG_M537x) := $(call cc-option,-mcpu=537x,-m5307)
cpuflags-$(CONFIG_M5307) := $(call cc-option,-mcpu=5307,-m5200)
cpuflags-$(CONFIG_M528x) := $(call cc-option,-mcpu=528x,-m5307)
cpuflags-$(CONFIG_M5275) := $(call cc-option,-mcpu=5275,-m5307)
cpuflags-$(CONFIG_M5272) := $(call cc-option,-mcpu=5272,-m5307)
cpuflags-$(CONFIG_M5271) := $(call cc-option,-mcpu=5271,-m5307)
cpuflags-$(CONFIG_M523x) := $(call cc-option,-mcpu=523x,-m5307)
cpuflags-$(CONFIG_M525x) := $(call cc-option,-mcpu=5253,-m5200)
cpuflags-$(CONFIG_M5249) := $(call cc-option,-mcpu=5249,-m5200)
cpuflags-$(CONFIG_M520x) := $(call cc-option,-mcpu=5208,-m5200)
cpuflags-$(CONFIG_M5206e) := $(call cc-option,-mcpu=5206e,-m5200)
cpuflags-$(CONFIG_M5206) := $(call cc-option,-mcpu=5206,-m5200)
KBUILD_AFLAGS += $(cpuflags-y)
KBUILD_CFLAGS += $(cpuflags-y)
KBUILD_CFLAGS += -pipe -ffreestanding
ifdef CONFIG_MMU
# without -fno-strength-reduce the 53c7xx.c driver fails ;-(
KBUILD_CFLAGS += -fno-strength-reduce -ffixed-a2
else
# we can use a m68k-linux-gcc toolchain with these in place
KBUILD_CFLAGS += -DUTS_SYSNAME=\"uClinux\"
KBUILD_CFLAGS += -D__uClinux__
KBUILD_AFLAGS += -D__uClinux__
endif
KBUILD_LDFLAGS := -m m68kelf
KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/m68k/kernel/module.lds
ifdef CONFIG_SUN3
LDFLAGS_vmlinux = -N
endif
CHECKFLAGS += -D__mc68000__
ifdef CONFIG_KGDB
# If configured for kgdb support, include debugging infos and keep the
# frame pointer
KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS)) -g
endif
#
# Select the assembler head startup code. Order is important. The default
# head code is first, processor specific selections can override it after.
#
head-y := arch/m68k/kernel/head.o
head-$(CONFIG_SUN3) := arch/m68k/kernel/sun3-head.o
head-$(CONFIG_M68000) := arch/m68k/68000/head.o
head-$(CONFIG_COLDFIRE) := arch/m68k/coldfire/head.o
core-y += arch/m68k/kernel/ arch/m68k/mm/
libs-y += arch/m68k/lib/
core-$(CONFIG_Q40) += arch/m68k/q40/
core-$(CONFIG_AMIGA) += arch/m68k/amiga/
core-$(CONFIG_ATARI) += arch/m68k/atari/
core-$(CONFIG_MAC) += arch/m68k/mac/
core-$(CONFIG_HP300) += arch/m68k/hp300/
core-$(CONFIG_APOLLO) += arch/m68k/apollo/
core-$(CONFIG_MVME147) += arch/m68k/mvme147/
core-$(CONFIG_MVME16x) += arch/m68k/mvme16x/
core-$(CONFIG_BVME6000) += arch/m68k/bvme6000/
core-$(CONFIG_SUN3X) += arch/m68k/sun3x/ arch/m68k/sun3/
core-$(CONFIG_SUN3) += arch/m68k/sun3/ arch/m68k/sun3/prom/
core-$(CONFIG_NATFEAT) += arch/m68k/emu/
core-$(CONFIG_M68040) += arch/m68k/fpsp040/
core-$(CONFIG_M68060) += arch/m68k/ifpsp060/
core-$(CONFIG_M68KFPU_EMU) += arch/m68k/math-emu/
core-$(CONFIG_M68000) += arch/m68k/68000/
core-$(CONFIG_COLDFIRE) += arch/m68k/coldfire/
all: zImage
lilo: vmlinux
if [ -f $(INSTALL_PATH)/vmlinux ]; then mv -f $(INSTALL_PATH)/vmlinux $(INSTALL_PATH)/vmlinux.old; fi
if [ -f $(INSTALL_PATH)/System.map ]; then mv -f $(INSTALL_PATH)/System.map $(INSTALL_PATH)/System.old; fi
cat vmlinux > $(INSTALL_PATH)/vmlinux
cp System.map $(INSTALL_PATH)/System.map
if [ -x /sbin/lilo ]; then /sbin/lilo; else /etc/lilo/install; fi
zImage compressed: vmlinux.gz
vmlinux.gz: vmlinux
ifndef CONFIG_KGDB
cp vmlinux vmlinux.tmp
$(STRIP) vmlinux.tmp
gzip -9c vmlinux.tmp >vmlinux.gz
rm vmlinux.tmp
else
gzip -9c vmlinux >vmlinux.gz
endif
bzImage: vmlinux.bz2
vmlinux.bz2: vmlinux
ifndef CONFIG_KGDB
cp vmlinux vmlinux.tmp
$(STRIP) vmlinux.tmp
bzip2 -1c vmlinux.tmp >vmlinux.bz2
rm vmlinux.tmp
else
bzip2 -1c vmlinux >vmlinux.bz2
endif
archclean:
rm -f vmlinux.gz vmlinux.bz2
archheaders:
$(Q)$(MAKE) $(build)=arch/m68k/kernel/syscalls all
install:
sh $(srctree)/arch/m68k/install.sh $(KERNELRELEASE) vmlinux.gz System.map "$(INSTALL_PATH)"
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