Re: [Qemu-devel] [PATCH v2 09/27] linux-user/sh4: Clean env->flags on signal boundaries

[Richard Henderson]

On 07/15/2017 12:59 PM, Aurelien Jarno wrote:
> On 2017-07-06 16:20, Richard Henderson wrote:
> > If a signal is delivered during the execution of a delay slot,
> > or a gUSA region, clear those bits from the environment so that
> > the signal handler does not start in that same state.
>
> How are signals delivered in linux-user? At least in system mode we
> forbid interrupts in the delay slot (see commit 5c6f3eb7db), as the
> manual clearly declare them as indivisible. Maybe the same should be
> done for linux-user?

Signals get queued, and delivered eventually.  I don't believe that we do 
anything to check that "signals can't be delivered yet" like we do in system mode.

> > +    regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
> >   }
> >   
> >   static void setup_frame(int sig, struct target_sigaction *ka,
>
> Why not using TB_FLAG_ENVFLAGS_MASK introduced earlier in this patch
> series?

I really want to clear these two sets.  I didn't want to assume that 
ENVFLAGS_MASK would never contain anything else.


r~