Re: [PATCH v3] Virtual memory size detection for 64 bit MIPS CPUs

[Guenter Roeck <guenter.roeck@ericsson.com>]

On Mon, Feb 01, 2010 at 06:44:21PM -0500, David Daney wrote:
> Guenter Roeck wrote:
> > Linux kernel 2.6.32 and later allocates memory from the top of virtual 
> > memory
> > space.
> > 
> > This patch implements virtual memory size detection for 64 bit MIPS CPUs
> > to avoid resulting crashes.
> > 
> > Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
> [...]
> >  
> > +static inline void cpu_set_vmbits(struct cpuinfo_mips *c)
> > +{
> > +   if (cpu_has_64bits) {
> > +           write_c0_entryhi(0xfffffffffffff000ULL);
> 
> macro indicated that we need to avoid hazards here on R4000.
> 
> Perhaps adding:
> 
>       back_to_back_c0_hazard();
> 
Compiler already added a nop, so I thought it wasn't necessary.
Doesn't hurt either, so I'll put it in.

Guenter