Re: bin/56471: ntpd dies at startup on macppc/current, sshd randomly dies

[Christos Zoulas <christos%zoulas.com@localhost>]

Good debugging. Let's make it look like the siginfo case then.

christos

> On Oct 30, 2021, at 8:48 AM, Jason Thorpe <thorpej%me.com@localhost> wrote:
> 
> 
>> On Oct 30, 2021, at 5:42 AM, Jason Thorpe <thorpej%me.com@localhost> wrote:
>> 
>>       /*
>>        * Make sure SRR1 hasn't been maliciously tampered with.  
>>        */     
>>       if (!PSL_USEROK_P(sc.sc_frame.srr1))
>>               return (EINVAL);
>> 
>> I’m pretty sure this is what is tripping in the failure case.
> 
> It’s worth noting that the siginfo case, which was always being used until very recently, simply does this:
> 
>                /*
>                 * Accept all user-settable bits without complaint;
>                 * userland should not need to know the machine-specific
>                 * MSR value.
>                 */
>                tf->tf_srr1 = (gr[_REG_MSR] & PSL_USERMOD) | PSL_USERSET;
> 
> I.e. does no checking, and simply forces it to what it should be (modulo accepting the user-settable bits, which in the OEA case are basically FP modes and single-stepping).
> 
> -- thorpej