[PATCH 3/4] Revert "ARM: mmu: use client domain permissions to support ARMv7 eXecute Never"

[Peter Rosin]

On 2021-09-19 09:06, Rouven Czerwinski wrote:
> Hi Peter,
> 
> while this may break for your board, it fundamentally introduces the
> possibility to speculate out of the RAM area on speculation happy

I'm aware of that. For me, speculation is not an issue since *any*
rogue code running on the embedded device in question is a major fail.

Also, from the cover letter:

"I'm going to follow up with patches. I very much realize that
these patches are most likely not acceptable as-is, but I do
include them since they are probably the best description of
where the problems are."

> processors. Are you calling into SAMA5D3 ROM code somewhere? If so an

*I* am not calling anything. Maybe the board code for sama5d3xek is,
but I have no idea as it's not "my" code. How can I figure out if it
does?

Cheers,
Peter

> exception can be added similar to the handling for the HAB code
> (arch/arm/cpu/mmu_early.c):
> 
> 	if (IS_ENABLED(CONFIG_HABV4) && IS_ENABLED(CONFIG_ARCH_IMX6))
> 		map_region(0x0, SZ_1M, PMD_SECT_DEF_CACHED);
> 
> which allows calls into the NXP boot ROM to retrieve the HAB status.