Re: [musl] [RFC v2 0/2] xtensa FDPIC port

[Max Filippov <jcmvbkbc@gmail.com>]

Hi Rich,

On Mon, May 6, 2024 at 7:47 AM Rich Felker <dalias@libc.org> wrote:
> Ping. Did this help with the xtensa fdpic work?

yeah, I think I've fixed all the issues raised in this review.
I've made an FDPIC ABI specification for xtensa and tried to get feed
from the Cadence Tensilica folks, but so far (4 weeks later) only got a
few questions, like "is there a plan to support windowed ABI" and "why
a11 is chosen as a GOT pointer". The spec is available here:
  https://github.com/jcmvbkbc/xtensa-abi/blob/master/fdpic-xtensa.txt
its current version is 1. I wonder if there's a place where I could post it
for a wider review?

I've updated the toolchain components to match the spec and support
both musl and uclibc-ng with single source. There are still some issues
in the binutils (e.g. static PIE support in the linker is broken ATM) and
in the compiler (libstdc++ build is broken for the uclibc-ng due to
dl_iterate_phdr interface difference), but none of it is directly related to
the xtensa port for musl.

libc-test results when running in the QEMU linux-user emulation are the
following:

FAIL src/functional/pthread_mutex_pi-static.exe [status 1]
FAIL src/functional/pthread_mutex_pi.exe [status 1]
FAIL src/functional/pthread_robust-static.exe [timed out]
FAIL src/functional/pthread_robust.exe [timed out]
FAIL src/functional/strptime-static.exe [status 1]
FAIL src/functional/strptime.exe [status 1]
FAIL src/math/acoshl.exe [status 1]
FAIL src/math/asinhl.exe [status 1]
FAIL src/math/erfcl.exe [status 1]
FAIL src/math/fma.exe [status 1]
FAIL src/math/fmal.exe [status 1]
FAIL src/math/lgammal.exe [status 1]
FAIL src/math/tgammal.exe [status 1]
FAIL src/regression/pthread-robust-detach-static.exe [status 1]
FAIL src/regression/pthread-robust-detach.exe [status 1]

mutex_pi and robust list failures are QEMU-linux-user specific and
they pass in system emulation and math test failures are due to the
ULP differences. I haven't had a chance to look at the strptime
failures, but IIRC they're also failing for the sh port.
The testing uncovered the following two issues in the QEMU-linux-user
emulation:
  https://mail.gnu.org/archive/html/qemu-devel/2024-03/msg06891.html
  https://mail.gnu.org/archive/html/qemu-devel/2024-03/msg06892.html

I will post v3 shortly.

-- 
Thanks.
-- Max