I'm considering changing SIG_ATOMIC_TYPE for CRIS (*-elf and *-linux-gnu) to the effect of #define SIG_ATOMIC_TYPE "int __attribute__((__aligned__(4)))" but that by itself doesn't work. It causes a SEGV on the 4.7 branch and no doubt also on trunk; the code is the same. From a gdb session it appears the type is expected to already exist as a built-in C type, like the (undecorated) "int" or "char" types, which are created much earlier in the same function.
How do I accomplish setting SIG_ATOMIC_TYPE as above? Ok, someone is going to ask "why": in the ABI used for CRIS, all types have byte alignment; structs are "packed". Linux could (AFAIU, theoretically) perform a context-switch if a process gets a page-fault writing to a "sigatomic_t" plain "int" that's straddling a page boundary where one of the pages isn't present (say, not yet in the TLB, or paged out). When the process gets to execute again, a signal could be waiting (say, SIGALRM) and the signal handler entered, but that plain "int" is not written in whole; presto, the access not atomic as seen by the signal-handler. (In case of a very possible thinko here, please don't forget the first question.) brgds, H-P
