On 8/19/24 12:41 PM, John Hubbard wrote:
On 8/18/24 8:55 PM, Muhammad Usama Anjum wrote:
On 8/7/24 3:22 PM, Muhammad Usama Anjum wrote:
On 5/9/24 11:16 AM, Kees Cook wrote:
...
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-
arm-linux-gnueabihf-gcc -Wall -Wno-nonnull -D_GNU_SOURCE=
-Wl,-z,max-page-size=0x1000 \
-fPIE -static-pie load_address.c -o
/home/usama/repos/kernel/linux_mainline/tools/testing/selftests/exec/load_address.static.0x1000
/usr/lib/gcc-cross/arm-linux-gnueabihf/12/../../../../arm-linux-gnueabihf/bin/ld:
cannot find rcrt1.o: No such file or directory
collect2: error: ld returned 1 exit status
make: *** [Makefile:39:
/home/usama/repos/kernel/linux_mainline/tools/testing/selftests/exec/load_address.static.0x1000]
Error 1
This appears to be because that particular cross compiler setup
(the libc part of the installation) fails to include rcrt1.o. I was
able to reproduce this on Ubuntu 23.04, using their standard arm
cross compilation packages for gcc and libc.
Also, -static-pie is what is causing the linker to look for rcrt1.o.
If you change the invocation from "-static-pie" to "-static -pie",
then linking succeeds.
Putting all of this together, I think we were are seeing is that
even though "-static-pie" was added to gcc 8.1+, and even though
the cross-compiler installation here shows gcc 12.3.0, the libc
support for that feature is lagging. In other words, the cross
installation of libc is effectively at something earlier than
gcc 8.1's needs.
So I think this means that we need to fix up the distros'packages,
and meanwhile, fall back to something like "-static-pie" for
selftests.
Or, another way of handling this would be to say, "gcc 8.1 is
sufficiently old, and cross-compiling of kselftests is sufficiently
rare, that we can wait for the cross compilers to catch up.
Until then, only native builds of kselftests are supported".
Shuah, you would know whether or not that's a reasonable thing
to claim--what do you think? I'm just trying to list all of the
options so that people can decide which way to go here.
thanks,
--
John Hubbard
NVIDIA
