powerpc: Don't silently handle machine checks from userspace

[Scott Wood]

On 11/06/2012 03:21:37 AM, Micha Nelissen wrote:
> From: Scott Wood [mailto:scottwood at freescale.com]
> > > Therefore I request to put this check back, and even to put the
> > > removed code at the top of the machine check handler because  
> there is
> > > no point in trying to recover from a user space bus error anyway.
> >
> > Why is there no point trying to recover?  For example, see  
> MCSR_ICPERR
> > and MCSR_DCPERR_MC in machine_check_e500mc.  The machine check is  
> just
> > letting us know that there was an error and the read-only cache got
> > dumped (i.e. it was a correctable error).
> 
> Oh I overlooked those cases; those correctable errors shouldn't be  
> bus errors for the user space process?
> 
> Hmm I guess there is no simple solution then, since the "recover"  
> function also prints the kernel messages about the machine check  
> being in kernel mode without having checked whether it really was in  
> kernel mode. In the past the user mode check was in between.

It shouldn't be that difficult to make it say "in user mode" or "in  
kernel mode" depending on which it was... or just remove that phrase  
altogether and let the following output indicate whether it was in  
kernel mode.

-Scott