Build error on ARM device due to ld flags

Thu Jan 24 20:33:36 CET 2019

On Thu, Jan 24, 2019 at 4:40 AM Sebastian Gottschall
<s.gottschall at newmedia-net.de> wrote:
>
> the kernel makefiles used for building on different architectures can be
> very different. (see kernel sourcdir/arch/arm/Makefile or arch/x86/Makefile)
> so some of them might also overwrite existing flags. what makes me wonder

The Makefile you mentioned for this system would seem to be
/usr/lib/modules/3.16.62-1-ARCH/build/arch/arm64/Makefile

% grep FLAG /usr/lib/modules/3.16.62-1-ARCH/build/arch/arm64/Makefile
LDFLAGS_vmlinux :=-p --no-undefined -X
CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET)
OBJCOPYFLAGS :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
GZFLAGS :=-9
LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
KBUILD_CFLAGS += -mgeneral-regs-only
KBUILD_CFLAGS += $(call cc-option, -mpc-relative-literal-loads)
KBUILD_CPPFLAGS += -mbig-endian
KBUILD_CPPFLAGS += -mlittle-endian
CHECKFLAGS += -D__aarch64__
KBUILD_CFLAGS_MODULE += -mcmodel=large
KBUILD_CFLAGS_MODULE += $(call cc-option, -mpc-relative-literal-loads)
export TEXT_OFFSET GZFLAGS

I actually don't see a plain LDFLAGS in it... just LDFLAGS_vmlinux.

> according to your build log you're setting various flags before
> entering the wireguard dir and compiling.
> why?

The packager on Arch (makepkg) has a config file (/etc/makepkg.conf)
that is read when a package is built by it which sets the build flags.
I just exported the flags therein on the shell then built manually to
keep it simple (ie without explaining about the packager).  I can tell
you that I get the identical error when I build manually as shown or
with the packager.

Curiously, I only get this error when I build Wireguard on this
platform (again reading from /etc/makepkg.conf which sets those
flags).  I can build anything else without the error (linux kernel,
ffmpeg, owncloud, nginx, etc.)

> Am 24.01.2019 um 09:57 schrieb John:
> > Thank you for the reply. What is odd is that I can build just fine on
> > Arch x86_64 which uses the identical LDFLAGS.  In any case, is your
> > recommendation to drop the -Wl portion of the LDFLAGS or so unset all
> > ie:
> >
> > unset CPPFLAGS CFLAGS CXXFLAGS LDFLAGS DEBUG_CFLAGS DEBUG_CXXFLAGS
> >
> > On Wed, Jan 23, 2019 at 11:02 PM Sebastian Gottschall
> > <s.gottschall at newmedia-net.de> wrote:
> >> -Wl etc is not a valid linker flag, its a flag for gcc which passes the
> >> following flags to the linker. so basicly the LDFLAGS are just wrong.
> >> in general no CFLAGS or LDFLAGS should be overriden, since wireguard
> >> uses exact he same flags which is used for compiling the kernel. so setting
> >> custom flags should be avoided
> >>
> >> Am 23.01.2019 um 22:07 schrieb John:
> >>> I am running Arch ARM (aarch64) on an ODROID-C2 using gcc v8.2.1.
> >>> Arch ARM which ships with the following LDFLAGS as defaults,
> >>> "-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now"
> >>>
> >>> When I build wireguard on this device as shown below, I get this error
> >>> but am unsure why:
> >>>
> >>> ld: unrecognized option '-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
> >>> ld: use the --help option for usage information
> >>> make[2]: *** [scripts/Makefile.build:393:
> >>> /scratch/WireGuard-0.0.20190123/src/wireguard.o] Error 1
> >>> make[1]: *** [Makefile:1358:
> >>> _module_/scratch/WireGuard-0.0.20190123/src] Error 2
> >>> make: *** [Makefile:36: module] Error 2
> >>>
> >>> If I remove the '-Wl' switch from the distro default, it builds
> >>> without error.  Any advice is appreciated.
> >>>
> >>> Complete build log and my FLAGS:
> >>>
> >>> % export CPPFLAGS="-D_FORTIFY_SOURCE=2"
> >>> % export CFLAGS="-march=armv8-a -O2 -pipe -fstack-protector-strong -fno-plt"
> >>> % export CXXFLAGS="-march=armv8-a -O2 -pipe -fstack-protector-strong -fno-plt"
> >>> % export LDFLAGS="-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now"
> >>> % export DEBUG_CFLAGS="-g -fvar-tracking-assignments"
> >>> % export DEBUG_CXXFLAGS="-g -fvar-tracking-assignments"
> >>>
> >>> % cd WireGuard-0.0.20190123
> >>> % make -j5 -C src
> >>> make: Entering directory '/scratch/WireGuard-0.0.20190123/src'
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/wg.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/config.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/show.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/terminal.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/ipc.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/mnlg.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/encoding.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/curve25519.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/setconf.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/genkey.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/showconf.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/pubkey.o
> >>>     CC      /scratch/WireGuard-0.0.20190123/src/tools/set.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/main.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/device.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/noise.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/peer.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/timers.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/queueing.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/send.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/receive.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/socket.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/hashtables.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/allowedips.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/ratelimiter.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/cookie.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/netlink.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20/chacha20.o
> >>>     PERLASM /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20/chacha20-arm64.S
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/poly1305/poly1305.o
> >>>     PERLASM /scratch/WireGuard-0.0.20190123/src/crypto/zinc/poly1305/poly1305-arm64.S
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20poly1305.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/blake2s/blake2s.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/curve25519/curve25519.o
> >>>     LD      /scratch/WireGuard-0.0.20190123/src/tools/wg
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/compat/siphash/siphash.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/compat/dst_cache/dst_cache.o
> >>>     CC [M]  /scratch/WireGuard-0.0.20190123/src/compat/udp_tunnel/udp_tunnel.o
> >>>     AS [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20/chacha20-arm64.o
> >>>     AS [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/poly1305/poly1305-arm64.o
> >>>     LD [M]  /scratch/WireGuard-0.0.20190123/src/wireguard.o
> >>> ld: unrecognized option '-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
> >>> ld: use the --help option for usage information
> >>> make[2]: *** [scripts/Makefile.build:393:
> >>> /scratch/WireGuard-0.0.20190123/src/wireguard.o] Error 1
> >>> make[1]: *** [Makefile:1358:
> >>> _module_/scratch/WireGuard-0.0.20190123/src] Error 2
> >>> make: *** [Makefile:36: module] Error 2
> >>> make: Leaving directory '/scratch/WireGuard-0.0.20190123/src'