Re: [Xen-devel] [PATCH RFC] fix sun6i crash on setup_pagetables

["Bamvor Jian Zhang" <bjzhang@xxxxxxxx>]

 >>>Written "Ian Campbell <ian.campbell@xxxxxxxxxx>"> On Wed, 2013-07-24 at 
 >>>19:33 +0100, Julien Grall wrote:
> > On 07/24/2013 01:14 PM, Bamvor Jian Zhang wrote: 
> > > this patch move set_processor_id in front of setup_pagetables 
> > > in order to fix crash when calling this_cpu in that functions. 
> > > the HPTIDR is unknown value according to ARM ARM 7AR(DDI0406C), 
> > > B4-1598. we should use it before using it. 
> > >  
> > > but i do not know why other board like arndale board. should 
> > > bootloader write this register? 
> >  
> > On the Arndale, by default the value of HPTIDR is equal to 0. So it 
> > works without any issue. 
>  
> Right, but strictly the register is undefined reset on reset. 
>  
> The bootloader cannot initialise it because the meaning is entirely OS 
> specific. 
>  
> > During the afternoon, I have noticed this error and send a similar 
> > patch few minutes ago. I also moved percpu_init_areas earlier. 
>  
> Right, I think this makes sense. 
>  
> I suppose I should just take your (Julien's) version of this patch? 
agree.
> > For the next patches, could you add the appropriate people? It will 
> > avoid to loose your patch with the other mail of the mailing list :). 
>  
> Yes please! 
i will, thanks. 
> >  
> > >  
> > > Signed-off-by: Bamvor Jian Zhang <bjzhang@xxxxxxxx> 
> > > --- 
> > >  xen/arch/arm/setup.c | 2 +- 
> > >  1 file changed, 1 insertion(+), 1 deletion(-) 
> > >  
> > > diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c 
> > > index 2f9fdc8..3bf1b40 100644 
> > > --- a/xen/arch/arm/setup.c 
> > > +++ b/xen/arch/arm/setup.c 
> > > @@ -437,6 +437,7 @@ void __init start_xen(unsigned long boot_phys_offset, 
> > >      cpus = smp_get_max_cpus(); 
> > >      cmdline_parse(device_tree_bootargs(device_tree_flattened)); 
> > >   
> > > +    set_processor_id(0); /* needed early, for this_cpu() */ 
> > >      setup_pagetables(boot_phys_offset, get_xen_paddr()); 
> > >      setup_mm(fdt_paddr, fdt_size); 
> > >   
> > > @@ -459,7 +460,6 @@ void __init start_xen(unsigned long boot_phys_offset, 
> > >      make_cpus_ready(cpus, boot_phys_offset); 
> > >   
> > >      percpu_init_areas(); 
> >  
> > I think you can also move percpu_init_areas earlier. 
> >  
> > > -    set_processor_id(0); /* needed early, for smp_processor_id() */ 
> > >      set_current((struct vcpu *)0xfffff000); /* debug sanity */ 
> > >      idle_vcpu[0] = current; 
> > >   
> > >  
> >  
>  
>  
>  
>  



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