On Thu, Sep 22, 2016 at 08:15:00AM +0000, Ed Schouten wrote: > Author: ed > Date: Thu Sep 22 08:14:59 2016 > New Revision: 306162 > URL: https://svnweb.freebsd.org/changeset/base/306162 > > Log: > Make it possible to safely use TPIDRURW from userspace. > > On amd64, arm64 and i386, we have the possibility to switch between TLS > areas in userspace. The nice thing about this is that it makes it easier > to do light-weight threading, if we ever feel like doing that. On armv6, > let's go into the same direction by making it possible to safely use the > TPIDRURW register, which is intended for this purpose.
What do you mean about 'possibility to switch between TLS areas in usermode' ? On x86, kernel switches %fs/%gs bases on the context switches. There is, indeed, a way to turn off this functionality, but it is somewhat unobvious, I have to admit. E.g. on Ivy+, RDFSBASE/RDGSBASE work. WRFSBASE/WRGSBASE are enabled, but they are de-facto not functional, since next context switch overrides the base, in default setup. _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
