Date: Sat, 11 Mar 2000 01:27:46 +0100 From: Martin Cracauer <cracauer@cons.org> To: "Daniel C. Sobral" <dcs@newsguy.com> Cc: Martin Cracauer <cracauer@cons.org>, Alfred Perlstein <bright@wintelcom.net>, Doug Rabson <dfr@nlsystems.com>, Martin Cracauer <cracauer@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/include npx.h Message-ID: <20000311012745.A23475@cons.org> In-Reply-To: <38C96E69.F002B997@newsguy.com>; from dcs@newsguy.com on Sat, Mar 11, 2000 at 06:51:37AM %2B0900 References: <200003101756.JAA90710@freefall.freebsd.org> <Pine.BSF.4.21.0003102057080.79394-100000@salmon.nlsystems.com> <20000310133936.B14279@fw.wintelcom.net> <20000310224345.A20522@cons.org> <38C96E69.F002B997@newsguy.com>
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In <38C96E69.F002B997@newsguy.com>, Daniel C. Sobral wrote: > Martin Cracauer wrote: > > > > > > > cracauer 2000/03/10 09:56:33 PST > > > > > > > > > > Modified files: > > > > > sys/i386/include npx.h > > > > > Log: > > > > > Change the default FPU control word so that exceptions for new > > > > > processes are now masked until set by fpsetmask(3). > > > > The only real drawback now is that our experienced user can't really > > choose anymore. In the past, you could change your own machines to > > masked exceptions, but now ports will stop inserting fpsetmask(3) > > calls soon and hence the other way for the cautios user will not work > > for long (unless the mass is high enough to catch those ports). But > > since you don't gain more from blindly inserted fpsetmask calls than > > from a default-to-masked the real paranoid people will maybe see the > > situation as improved, not weakend. > > Isn't there any way to make this sysctl'able? That is not a useful feature, IMHO. What you want is to say "hey, I have this application that doesn't set the control word and that I want shot on float errors". You want this for specific applications, not for the whole system. If you don't have the source for the application, you can't insert a fpsetmask(). The best way would be to be able to set this for arbitray binaries without recompiling or relinking, a'la' brandelf(1). That needs more thought than can be done until 4.0. Martin -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Martin Cracauer <cracauer@cons.org> http://www.cons.org/cracauer/ Tel.: (private) +4940 5221829 Fax.: (private) +4940 5228536 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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