Re: [patch 5/6] sparc: Use preempt_schedule_irq

From: Thomas Gleixner
Date: Tue Sep 17 2013 - 19:24:08 EST


On Tue, 17 Sep 2013, David Miller wrote:
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Date: Tue, 17 Sep 2013 18:53:08 -0000
>
> > bne,pn %xcc, kern_fpucheck
> > - sethi %hi(PREEMPT_ACTIVE), %l6
> > - stw %l6, [%g6 + TI_PRE_COUNT]
> > - call schedule
> > + call preempt_schedule_irq
> > nop
>
> You've put the function call into the delay slot of the branch,
> which you don't want to do.
>
> That's, btw, why we indent instructions with an extra space like
> that, to emphasize that it's a delay slot of the preceeding
> branch.

I knew that I'd get it wrong :) So is adding another nop the right
thing to do ?

bne,pn %xcc, kern_fpucheck
- sethi %hi(PREEMPT_ACTIVE), %l6
- stw %l6, [%g6 + TI_PRE_COUNT]
- call schedule
+ nop
+ call preempt_schedule_irq
nop

Thanks,

tglx
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