[U-Boot] [PATCH v4 1/2] Reserve secure memory

[York Sun]

On 11/16/2015 09:11 AM, Joakim Tjernlund wrote:
> On Mon, 2015-11-16 at 08:34 -0800, York Sun wrote:
>> Secure memory is at the end of memory, separated and reserved
>> from OS, tracked by gd->secure_ram. Secure memory can host
>> MMU tables, security monitor, etc.
> 
> Don't see the difference with pram here?
> Also, do you really wan't to hide the memory from Linux or will
> a resv map do? You get a lot of small TLB maps if memory is non power of 2
> 

Jocke,

It is different from pram. First, it is at the end of memory, not the top of
u-boot memory. The difference is where u-boot runs in memory. Second, the size
is much bigger, even this patch doesn't limit the size. In my system, I reserve
2MB memory.

Since we already have CONFIG_SYS_MEM_TOP_HIDE, I think it is a good way to
reserve big chunk of memory without fragmentation. In my system, the end of
usable memory is aligned with 512MB.

York