Messages in this thread | | | Date | Mon, 5 Aug 2002 23:35:42 +0200 | From | Andi Kleen <> | Subject | Re: context switch vs. signal delivery [was: Re: Accelerating user mode linux] |
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On Mon, Aug 05, 2002 at 10:30:06PM +0100, Jamie Lokier wrote: > Andi Kleen wrote: > > + err |= setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0], > > + (ka->sa.sa_flags&SA_NOFP)); > > > err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate, > > - regs, set->sig[0]); > > + regs, set->sig[0], !!(ka->sa.sa_flags&SA_NOFP)); > > 1: Why the inconsistency between the two ways the SA_NOFP flag is checked?
I don't remember. Probably there was some reason in an earlier version of the code. The !! could be probably removed now.
> > 2: What happens when the user's signal handler decides it wants to save > the FPU state itself (after all) and proceed with some FPU use. Will > sigreturn restore the user-saved FPU state? Just curious.
Nope it won't because there is no saved state. The previous context's FPU state will be silently corrupted.
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