Re: [Minios-devel] [PATCH 03/40] arm64: add the boot code

[Huang Shijie <shijie.huang@xxxxxxx>]

On Thu, Nov 09, 2017 at 10:33:20AM +0000, Julien Grall wrote:
Hi Julien,
> > > > Why should we remove it after the MMU is enabled?
> > > > 
> > > > Is there any problem if we keep it?
> > > 
> > > Well, after the MMU is enabled the OS should never address the identity
> > > mapping. If there are a programming error, that region may be accessed by
> > > errror. So instead of getting a fault you would corrupt memory. The latter
> > > is really hard to debug.
> > 
> > Okay. I will clear it to 0 in next version.
> 
> I think this would not be enough. 0 could be a valid physical address....
> What you want to do is set TCR_EL1.EPD0 to 1. That will disable translations
> using TTBR0_EL1.
Got it.

thanks
Huang Shijie

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