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From: Peter Rosin <peda@axentia.se>
To: Rouven Czerwinski <r.czerwinski@pengutronix.de>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Ahmad Fatoum <ahmad@a3f.at>
Cc: Barebox List <barebox@lists.infradead.org>
Subject: Re: [PATCH 3/4] Revert "ARM: mmu: use client domain permissions to support ARMv7 eXecute Never"
Date: Sun, 19 Sep 2021 09:50:56 +0200	[thread overview]
Message-ID: <02b09328-e300-f36e-4cc4-daa7afb47ad5@axentia.se> (raw)
In-Reply-To: <e14fb2eb0ea344ac272b823c51ee3a4049a51c33.camel@pengutronix.de>

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.

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  reply	other threads:[~2021-09-19  7:53 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-17 22:37 at91 sama5d3 "regressions" Peter Rosin
2021-09-17 22:39 ` [PATCH 1/4] common.h: reintroduce region_overlap() as, old_region_overlap() Peter Rosin
2021-09-17 22:39 ` [PATCH 2/4] ARM: copy data if there is a region overlap Peter Rosin
2021-09-17 22:40 ` [PATCH 3/4] Revert "ARM: mmu: use client domain permissions to support ARMv7 eXecute Never" Peter Rosin
2021-09-19  7:06   ` Rouven Czerwinski
2021-09-19  7:50     ` Peter Rosin [this message]
2021-09-19 20:33       ` Peter Rosin
2021-09-20  9:14       ` Ahmad Fatoum
2021-09-20 10:22         ` Peter Rosin
2021-09-17 22:41 ` [PATCH 4/4] lds: the RO_DATA_SECTION macro does not work on my SAMA5D3 board Peter Rosin
2021-09-17 23:57 ` at91 sama5d3 "regressions" Peter Rosin
2021-09-19  6:32   ` Peter Rosin
2021-09-22  7:06     ` Ahmad Fatoum
2021-09-22  7:41       ` Peter Rosin

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