Re: [PATCH 0/2] arch: arm: gic-v3-its: stop abusing the device tree

Bharat Gooty
2021-10-28T11:35:51Z

On Thu, Oct 28, 2021 at 4:52 PM Michael Walle <michael@walle.cc> wrote:

> Am 2021-10-28 11:20, schrieb Bharat Gooty:
> > On Thu, Oct 28, 2021 at 2:33 PM Marc Zyngier <maz@kernel.org> wrote:
>
> > For GIC V3, once the LPI tables are programmed, we can not update it,
> > unless we do a reset.
> > For the kexec kernel, where the reboot does not happen, in this case,
> > during the new kernel boot, the new LPI tables address will not be
> > updated.
>
> kexec.. this should have really gone into both the commit message _and_
> the kconfig menu. In fact, it is really just a workaround for the kexec
> case. If I understand it correctly, the kernel is able to communicate
> the reserved memory area, but only if you have EFI support. So, as a
> workaround, the bootloader can pre-allocate the memory and put it in
> the device tree, which is then passed from the old to the new kernel
> and the reservation is preserved. Correct, Marc?
>
> If EFI support is enabled, that's true, Pre-allocate the memory and Kernel
can get that memory using EFI.
What if EFI support is not enabled, like in a Broadcom NS3 or NXP platform?
What is your suggestion for solving the kexec problem?

> But all of this doesn't need any new device tree node.
>
> -michael
>

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