Peter Zijlstra wrote: > On Fri, 2010-01-22 at 12:32 +0530, Srikar Dronamraju wrote: > >> 2. XOL vma vs Emulation vs Single Stepping Inline vs using Protection >> Rings. >> XOL VMA is an additional process address vma. This is >> opposition to add an additional vma without user actually >> requesting for the same. >> >> XOL vma and single stepping inline are the two architecture >> independent implementations. While other implementations are >> more architecture specific. Single stepping inline wouldnt go >> well with multithreaded process. >> >> Even though XOL vma has its own issues, we will go with it since >> other implementations seem to have more complications. >> >> we would look forward to implementing boosters later. >> Later on, if we come across another techniques with lesser >> side-effects than the XOL vma, we would switch to using them. > > How about modifying glibc to reserve like 64 bytes on the TLS structure > it has and storing the ins and possible boost jmp there? Since each > thread can only have a single trap at any one time that should be > enough.
Hmm, it is a good idea. Well, we'll have a copy of original insn in kernel, but it could be simpler than managing XOL vma. :-) Thank you, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division e-mail: mhira...@redhat.com
