Re: [PATCH 1/2] ARM: i.MX6: Enable PBL_VERIFY_PIGGY with HABV4 support

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, Feb 19, 2025 at 11:43:29AM +0100, Marco Felsch wrote:
> Hi Sascha,
> 
> On 25-02-18, Sascha Hauer wrote:
> > Some i.MX6 configurations use the xload mechanism. With this the ROM
> > only loads and verifies the PBL. The PBL will then load barebox proper.
> > Without verification the barebox proper binary is untrusted and could be
> > modified. Select PBL_VERIFY_PIGGY when HABV4 is enabled to ensure the
> > barebox proper binary has not been tempered with.
> > 
> > boards not using the xload mechanism don't need this option, but there
> > is no good way to detect currently if the xload mechanism is used, so
> > these boards will have to live with a slightly increased binary size
> > for now.
> 
> I hav no objections but do you have numbers? There are many i.MX6 based
> systems which do use a spi-nor with limited amount of space already
> facing size issues since barebox is becoming bigger and bigger.

Enabling PBL_VERIFY_PIGGY increases the PBL by about ~6k on ARM/ARM64.

We could add the select to MCI_IMX_ESDHC_PBL instead. The SPI xload
code doesn't have a corresponding Kconfig symbol though, so we would
have to add that first.

Sascha

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