Rich Felker 1281779330 fix broken atomic store on powerpc[64] ... in our memory model, all atomics are supposed to be full barriers; stores are not release-only. this is important because store is used as an unlock operation in places where it needs to acquire the waiter count to determine if a futex wake is needed. at least in the malloc-internal locks, but possibly elsewhere, soft deadlocks from missing futex wake (breakable by poking the threads to restart the syscall, e.g. by attaching a tracer) were reported to occur. once the malloc lock is replaced with Jens Gustedt's new lock implementation (see commit 47d0bcd476), malloc will not be affected by the issue, but it's not clear that other uses won't be. reducing the strength of the ordering properties required from a_store would require a thorough analysis of how it's used. to fix the problem, I'm removing the powerpc[64]-specific a_store definition; now, the top-level atomic.h will implement a_store using a_barrier on both sides of the store. it's not clear to me yet whether there might be issues with the other atomics. it's possible that a_post_llsc needs to be replaced with a full barrier to guarantee the formal semanics we want, but either way I think the difference is unlikely to impact the way we use them.		2018-09-14 10:47:16 -04:00
..
aarch64	aarch64: add HWCAP_ flags from linux v4.17	2018-06-19 13:27:17 -04:00
arm	define and use internal macros for hidden visibility, weak refs	2018-09-05 14:05:14 -04:00
generic/bits	move inclusion of linux headers for kd.h, soundcard.h, vt.h to bits	2018-07-20 01:06:41 -04:00
i386	add support for arch-specific ptrace command macros	2018-07-17 22:25:08 -04:00
m68k	add support for arch-specific ptrace command macros	2018-07-17 22:25:08 -04:00
microblaze	work around broken kernel struct ipc_perm on some big endian archs	2018-06-20 00:07:09 -04:00
mips	apply hidden visibility to sigreturn code fragments	2018-09-12 14:34:34 -04:00
mips64	apply hidden visibility to sigreturn code fragments	2018-09-12 14:34:34 -04:00
mipsn32	apply hidden visibility to sigreturn code fragments	2018-09-12 14:34:34 -04:00
or1k	fix TLS layout of TLS variant I when there is a gap above TP	2018-06-02 19:38:44 -04:00
powerpc	fix broken atomic store on powerpc[64]	2018-09-14 10:47:16 -04:00
powerpc64	fix broken atomic store on powerpc[64]	2018-09-14 10:47:16 -04:00
s390x	add support for arch-specific ptrace command macros	2018-07-17 22:25:08 -04:00
sh	apply hidden visibility to sigreturn code fragments	2018-09-12 14:34:34 -04:00
x32	apply hidden visibility to sigreturn code fragments	2018-09-12 14:34:34 -04:00
x86_64	apply hidden visibility to sigreturn code fragments	2018-09-12 14:34:34 -04:00