Description of problem:

SLOF is always built as a big endian target. To be built on a little endian host, SLOF makefile adds "-m64 -mbig" to gcc flags.

But the build fails on the link edition:

 ====== Building slof ======
make -C slof BOARD=qemu PLATFORM= FLAG="-DRTAS_NVRAM -DBROKEN_SC1 -DDHCPARCH=0x0C " TARG=ppc64 RELEASE=-DRELEASE=\"\\\"git-749c50b84b83a9b9\\\"\"
make[2]: Entering directory `/home/lvivier/SLOF/board-qemu/slof'
gcc -m64 -mbig -mabi=elfv1 -T/home/lvivier/SLOF/slof/OF.lds /home/lvivier/SLOF/slof/ofw.o version.o paflof.o helpers.o allocator.o \
/home/lvivier/SLOF/slof/entry.o romfs.o OF.o nvramlog.o /home/lvivier/SLOF/board-qemu/llfw/board_io.o \
/home/lvivier/SLOF/board-qemu/llfw/io_generic_lib.o -static -nostdlib -Wl,-q,-n /home/lvivier/SLOF/lib/libbootmsg.a /home/lvivier/SLOF/lib/libelf.a /home/lvivier/SLOF/lib/libhvcall.a /home/lvivier/SLOF/lib/libvirtio.a /home/lvivier/SLOF/lib/libusb.a /home/lvivier/SLOF/lib/libnvram.a /home/lvivier/SLOF/lib/libveth.a /home/lvivier/SLOF/lib/libe1k.a /home/lvivier/SLOF/lib/libc.a -o paflof
/home/lvivier/SLOF/slof/ofw.o:(.slof.loader+0x5c): undefined reference to `.patch_broken_sc1'

$ file /home/lvivier/SLOF/slof/ofw.o
/home/lvivier/SLOF/slof/ofw.o: ELF 64-bit MSB relocatable, 64-bit PowerPC or cisco 7500, version 1 (SYSV), not stripped

patch_broken_sc1 is in libhvcall:
$ nm lib/libhvcall/brokensc1.o|grep patch
0000000000000000 D patch_broken_sc1
$ file lib/libhvcall/brokensc1.o
lib/libhvcall/brokensc1.o: ELF 64-bit MSB relocatable, 64-bit PowerPC or cisco 7500, version 1 (SYSV), not stripped

Version-Release number of selected component (if applicable):

gcc-4.8.5-4.el7.ppc64le
binutils-2.23.52.0.1-55.el7.ppc64le

How reproducible:

100%

Steps to Reproduce:
1. git clone git://git.qemu-project.org/SLOF.git
2. cd SLOF
3. make V=2 qemu


Actual results:

Error: undefined reference to `.patch_broken_sc1'

Expected results:

Build slof without error.

Additional info:

It seems that "gcc" adds "--oformat elf32-powerpc" in case of "-mbig" even if the target is 64bit:

    *link_target:
    %{mlittle|mlittle-endian:;mbig|mbig-endian: --oformat elf32-powerpc;mcall-i960-old:;:}

If we remove the "-mbig" from the command line, all works fine as ld will use for output format the same as the input format (elf64-powerpc).

This can be related to BZ1279172, and this patch should fix this one too:
https://bugzilla.redhat.com/attachment.cgi?id=1091247