Re: [PATCH] Revert "arm: bootm: Disable LMB reservation for command line and board info on arm64"

[Tom Rini <trini@konsulko.com>]

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On Sun, Aug 08, 2021 at 05:25:33PM +0200, Marek Vasut wrote:
> On 8/8/21 4:54 PM, Tom Rini wrote:
> 
> [...]
> 
> > > > I expect it was not simply because up
> > > > until rather recently we didn't have any checks for "don't overwrite
> > > > specific areas of memory" other than right before firing off the OS (and
> > > > modify whatever memory you want to modify is a feature not a bug).
> > > 
> > > The LMB has been around since forever though ?
> > 
> > Yes, LMB has been around since the PowerPC device tree days I suspect (I
> > didn't dig that far back), but only used outside of the "don't overwrite
> > the running U-Boot while we relocate device tree / initrd before booting
> > OS" since 2018 or so.
> 
> So, are we using LMB for two different things now ?

For "now" == "2.5 years", yes, we've used the "LMB stops us from
overwriting running U-Boot" as part of addressing the CVEs I quoted.

-- 
Tom

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