Date: Fri, 23 Feb 2001 13:10:26 -0800 From: Peter Wemm <peter@netplex.com.au> To: Bruce Evans <bde@zeta.org.au> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/conf options.i386 options.pc98 src/sys/i386/conf NOTES src/sys/i386/i386 genassym.c machdep.c mp_machdep.c pmap.c swtch.s sys_machdep.c vm_machdep.c src/sys/i386/include globaldata.h pcb.h pcb_ext.h ... Message-ID: <200102232110.f1NLAQf53015@mobile.wemm.org> In-Reply-To: <Pine.BSF.4.21.0102231850270.9424-100000@besplex.bde.org>
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Bruce Evans wrote: > On Thu, 22 Feb 2001, Peter Wemm wrote: > > > peter 2001/02/22 17:25:02 PST > > > > Modified files: > > sys/conf options.i386 options.pc98 > > sys/i386/conf NOTES > > sys/i386/i386 genassym.c machdep.c mp_machdep.c pmap.c > > swtch.s sys_machdep.c vm_machdep.c > > sys/i386/include globaldata.h pcb.h pcb_ext.h > > sys/i386/svr4 svr4_machdep.c > > sys/pc98/i386 machdep.c > > Log: > > Activate USER_LDT by default. The new thread libraries are going to > > depend on this. The linux ABI emulator tries to use it for some linux > > binaries too. VM86 had a bigger cost than this and it was made default > > a while ago. > > > > Reviewed by: jhb, imp > > Arrgh. This activates it as standard. It should only be activated by > default in GENERIC. I could always invert it to a negative option.. NO_USER_LDT. > Why use this mistake in new libraries? Because it is the most efficient way to get thread local storage with a shared address space without having to use the hideous stack hacking in liblinuxthreads. > I use it > to run Wine, but don't like it's cost and don't trust its security. It's cost? about 1000 bytes and two tests in cpu_switch()? (I think the test in cpu_switch() can be reduced to one test when switching between two default ldt processes... but I have not looked too closely) > Bruce > > Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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