This patch disables use of 64-bit atomics for MIPS n32 to fix the
problems with unaligned semaphores.
Before 64-bit atomics are used for anything for which such alignment
issues do not arise, and before the addition of any new ILP32 ports
with 64-bit semaphores for which the ABI can be set to have the
greater alignment (AARCH64?), a better approach will need to be
established that allows architectures to declare their 64-bit atomics
availability accurately, without doing so causing inappropriate use of
such atomics on unaligned semaphores.
Tested for MIPS n32 that this fixes the nptl/tst-sem3 failure.
* sysdeps/mips/bits/atomic.h [_MIPS_SIM == _ABIN32]
(__HAVE_64B_ATOMICS): Define to 0.
This sets __HAVE_64B_ATOMICS if provided. It also sets
USE_ATOMIC_COMPILER_BUILTINS to true if the existing atomic ops use the
__atomic* builtins (aarch64, mips partially) or if this has been
tested (x86_64); otherwise, this is set to false so that C11 atomics will
be based on the existing atomic operations.
I've moved the MIPS port from ports to the main sysdeps hierarchy.
Beyond the README update, the move of the files was simply
git mv ports/sysdeps/mips sysdeps/mips
git mv ports/sysdeps/unix/mips sysdeps/unix/mips
git mv ports/sysdeps/unix/sysv/linux/mips sysdeps/unix/sysv/linux/mips
and in addition to the ChangeLog entries here, I put a note at the top
of ports/ChangeLog.mips similar to those in other files.
Tested that disassembly of installed shared libraries for mips is the
same before and after this patch (except for ld.so where paths in
assertions are involved, as for arm).
* sysdeps/mips: Move directory from ports/sysdeps/mips.
* sysdeps/unix/mips: Move directory from ports/sysdeps/unix/mips.
* sysdeps/unix/sysv/linux/mips: Move directory from
ports/sysdeps/unix/sysv/linux/mips.
* README: Update listing for mips-*-linux-gnu and
mips64-*-linux-gnu.
* sysdeps/mips: Move directory to ../sysdeps/mips.
* sysdeps/unix/mips: Move directory to ../sysdeps/unix/mips.
* sysdeps/unix/sysv/linux/mips: Move directory to
../sysdeps/unix/sysv/linux/mips.
