Re: [PATCH v4 15/17] x86/traps: Fixup general protection faults caused by UMIP

[Andy Lutomirski]

On Thu, Feb 23, 2017 at 2:15 PM, Ricardo Neri
<ricardo.neri-calderon@xxxxxxxxxxxxxxx> wrote:
> On Thu, 2017-02-23 at 10:27 +0100, Peter Zijlstra wrote:
>> On Wed, Feb 22, 2017 at 10:37:04PM -0800, Ricardo Neri wrote:
>> > @@ -492,6 +493,9 @@ do_general_protection(struct pt_regs *regs, long error_code)
>> >     RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
>> >     cond_local_irq_enable(regs);
>> >
>> > +   if (user_mode(regs) && (fixup_umip_exception(regs) == true))
>> > +           return;
>>
>> I'm thinking
>>
>>       if (user_mode(regs) && fixup_umip_exception(regs))
>>               return;
>>
>> is actually easier to read.
>
> In a previous version Andy Lutomirsky suggested that
>         if (user_mode(regs) && (fixup_umip_exception(regs) == 0))
>
> was easier to read :). Although at the time fixup_umip_exception
> returned a numeric value. Now it only returns true/false for
> successful/failed emulation. If with true/false not comparing to true
> makes it easier to read, I will make the change.

I think == true is silly :)

--Andy