Writing Assembly on OpenBSD (x86) (2012)

What I'm curious about is whether there's a good writeup of what you need to do to handle the (presumably) ASLR that OpenBSD has.

I've been having a hell of a time figuring out what's going on when I try to port Myrddin -- the code I generate will often segfault, on a string that GDB seems to think is perfectly valid, and happily prints. Some of the strings have clearly wonky addresses, (eg, within the zero page), others don't look insane.

What is the purpose of the .note section? If it is left out, it appears from ktrace that the kernel assumes the binary uses some other ABI, e.g., Linux, etc. (compat_linux, etc.) and the /emul shadow directory gets searched.

OpenBSD is a great platform to find those bugs in your asm/c. Segfaults that would not happen on Linux. (e.g. closing a file before exit that you never opened). http://nixdoc.net/man-pages/OpenBSD/malloc.conf.5.html is also another great place to tweak memory allocation behaviors to find those application corner cases that break.