linux_dsm_epyc7002/arch/arm/vdso/Makefile
Nathan Lynch 3473f26592 ARM: 8405/1: VDSO: fix regression with toolchains lacking ld.bfd executable
The Sourcery CodeBench Lite 2014.05 toolchain (gcc 4.8.3, binutils
2.24.51) has a GCC which implements -fuse-ld, and it doesn't include
the gold linker, but it lacks an ld.bfd executable in its
installation.  This means that passing -fuse-ld=bfd fails with:

      VDSO    arch/arm/vdso/vdso.so.raw
    collect2: fatal error: cannot find 'ld'

Arguably this is a deficiency in the toolchain, but I suspect it's
commonly used enough that it's worth accommodating: just use

cc-ldoption (to cause a link attempt) instead of cc-option to test
whether we can use -fuse-ld.  So -fuse-ld=bfd won't be used with this
toolchain, but the build will rightly succeed, just as it does for
toolchains which don't implement -fuse-ld (and don't use gold as the
default linker).

Note: this will change the failure mode for a corner case I was trying
to handle in d2b30cd4b7, where the toolchain defaults to the gold
linker and the BFD linker is not found in PATH, from:

      VDSO    arch/arm/vdso/vdso.so.raw
    collect2: fatal error: cannot find 'ld'

i.e. the BFD linker is not found, to:

      OBJCOPY arch/arm/vdso/vdso.so
    BFD: arch/arm/vdso/vdso.so: Not enough room for program headers, try
    linking with -N

that is, we fail to prevent gold from being used as the linker, and it
produces an object that objcopy can't digest.

Reported-by: Baruch Siach <baruch@tkos.co.il>
Tested-by: Baruch Siach <baruch@tkos.co.il>
Tested-by: Raphaël Poggi <poggi.raph@gmail.com>
Fixes: d2b30cd4b7 ("ARM: 8384/1: VDSO: force use of BFD linker")
Cc: stable@vger.kernel.org
Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-07-31 18:54:45 +01:00

79 lines
2.3 KiB
Makefile

hostprogs-y := vdsomunge
obj-vdso := vgettimeofday.o datapage.o
# Build rules
targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.so.raw vdso.lds
obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
ccflags-y := -fPIC -fno-common -fno-builtin -fno-stack-protector
ccflags-y += -DDISABLE_BRANCH_PROFILING
VDSO_LDFLAGS := -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1
VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096
VDSO_LDFLAGS += -nostdlib -shared
VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--build-id)
VDSO_LDFLAGS += $(call cc-ldoption, -fuse-ld=bfd)
obj-$(CONFIG_VDSO) += vdso.o
extra-$(CONFIG_VDSO) += vdso.lds
CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
CFLAGS_REMOVE_vdso.o = -pg
# Force -O2 to avoid libgcc dependencies
CFLAGS_REMOVE_vgettimeofday.o = -pg -Os
CFLAGS_vgettimeofday.o = -O2
# Disable gcov profiling for VDSO code
GCOV_PROFILE := n
# Force dependency
$(obj)/vdso.o : $(obj)/vdso.so
# Link rule for the .so file
$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE
$(call if_changed,vdsold)
$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/vdsomunge FORCE
$(call if_changed,vdsomunge)
# Strip rule for the .so file
$(obj)/%.so: OBJCOPYFLAGS := -S
$(obj)/%.so: $(obj)/%.so.dbg FORCE
$(call if_changed,objcopy)
# Actual build commands
quiet_cmd_vdsold = VDSO $@
cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \
-Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
quiet_cmd_vdsomunge = MUNGE $@
cmd_vdsomunge = $(objtree)/$(obj)/vdsomunge $< $@
#
# Install the unstripped copy of vdso.so.dbg. If our toolchain
# supports build-id, install .build-id links as well.
#
# Cribbed from arch/x86/vdso/Makefile.
#
quiet_cmd_vdso_install = INSTALL $<
define cmd_vdso_install
cp $< "$(MODLIB)/vdso/vdso.so"; \
if readelf -n $< | grep -q 'Build ID'; then \
buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
first=`echo $$buildid | cut -b-2`; \
last=`echo $$buildid | cut -b3-`; \
mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
ln -sf "../../vdso.so" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
fi
endef
$(MODLIB)/vdso: FORCE
@mkdir -p $(MODLIB)/vdso
PHONY += vdso_install
vdso_install: $(obj)/vdso.so.dbg $(MODLIB)/vdso FORCE
$(call cmd,vdso_install)