Date: Sun, 5 Oct 2003 13:46:52 -0400 (EDT) From: Daniel Eischen <eischen@vigrid.com> To: Jake Burkholder <jake@locore.ca> Cc: sparc64@freebsd.org Subject: Re: Review for libpthread support Message-ID: <Pine.GSO.4.10.10310051338550.68-100000@pcnet5.pcnet.com> In-Reply-To: <200310051319.29901.jake@locore.ca>
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On Sun, 5 Oct 2003, Jake Burkholder wrote: > On Sunday 05 October 2003 12:21, Daniel Eischen wrote: > > Hi guys, > > > > I have a patch for adding libpthread support for sparc64. It's jake's > > patch, with a few mods by myself. I'd like for some folks to look it > > over. I haven't tested it; I need a couple of questions answered > > first so I can fill in a missing piece. > > > > o Can someone look at the end of __thr_getcontext (line 524 of > > the patch)? I need to test %i2 for NULL and branch to 1 if true. > > > > +/* bz %i2, 1f */ > > + stx %i1, [%i2] > > +1: ldx [%sp], %i1 /* restore %i1 */ > > + ldx [%sp + 8], %i2 /* restore %i2 */ > > brz. Beware of delay slots, the instruction after a branch is executed before > the branch is taken. OK. > > Use the locals as temporaries instead of using the stack, eg What if a thread gets interrupted while using locals? _thr_setcontext() is suppose to be able to resume a thread that was interrupted anywhere. What if some library function used locals, thread T1 had a page fault, and it's context was exported back to libpthread? The library may run other threads before resuming T1 again. > > mov %i0, %l0 > mov %i1, %l1 > mov %i2, %l2 > ... > ldx [%l0 + MC_TPC], %l4 > ldx [%l0 + MC_TNPC], %l3 > brz %l1, 1f > nop > stx %l2, [%l1] > 1: jmpl %l3, %g0 > return %l4 > > Jake > > > > > What's the magic instruction I should use? > > > > o Can someone look over the context saving/restoring in general? > > I have a feeling there should be more to __thr_getcontext than > > there is. > > > > The patch is at: > > > > http://people.freebsd.org/~deischen/kse/libpthread_sparc64.diffs > > > > I'm not subscribed to this list, so please keep me on the CC. > > > > Thanks, > -- Dan Eischen
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