Le 06/06/2020 à 01:54, Will Springer a écrit :

On Saturday, May 30, 2020 3:17:24 PM PDT Will Springer wrote:

quoted

On Saturday, May 30, 2020 8:37:43 AM PDT Christophe Leroy wrote:

quoted

There is a series at
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=173231
to switch powerpc to the Generic C VDSO.

Can you try and see whether it fixes your issue ?

Christophe

Sure thing, I spotted that after making the initial post. Will report
back with results.

Will [she/her]

Sorry for the wait, I just sat down to work on this again yesterday.

Tested this series on top of stable/linux-5.7.y (5.7.0 at the time of
writing), plus the one-line signal handler patch. Had to rewind to the
state of powerpc/merge at the time of the mail before the patch would
apply, then cherry-picked to 5.6 until I realized the patchset used some
functionality that didn't land until 5.7, so I moved it there.

Good news is that `date` now works correctly with the vdso call in 32-bit
LE. Bad news is it seems to have broken things on the 64-bit side—in my
testing, Void kicks off runit but hangs after starting eudev, and in a
Debian Stretch system, systemd doesn't get to the point of printing
anything whatsoever. (I had to `init=/bin/sh` to confirm the date worked
in ppcle, although in ppc64le running `date` also hung the system when it
made the vdso call...) Not sure how to approach debugging that, so I'd
appreciate any pointers.

Does it breaks only ppc64le vdso or also ppc64 (be) vdso ?

I never had a chance to run any test on ppc64 as I only have a kernel 
cross compiler.

Would you have a chance to build and run vdsotest from 
https://github.com/nathanlynch/vdsotest ?

Thanks
Christophe