Re: [PATCH 4.9 39/92] efi/arm: Revert deferred unmap of early memmap mapping

[Ard Biesheuvel]

On Thu, 29 Nov 2018 at 16:02, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Thu, Nov 29, 2018 at 03:28:44PM +0100, Ard Biesheuvel wrote:
> > On Thu, 29 Nov 2018 at 15:21, Greg Kroah-Hartman
> > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > 4.9-stable review patch.  If anyone has any objections, please let me know.
> > >
> > > ------------------
> > >
> > > [ Upstream commit 33412b8673135b18ea42beb7f5117ed0091798b6 ]
> > >
> > > Commit:
> > >
> > >   3ea86495aef2 ("efi/arm: preserve early mapping of UEFI memory map longer for BGRT")
> > >
> > > deferred the unmap of the early mapping of the UEFI memory map to
> > > accommodate the ACPI BGRT code, which looks up the memory type that
> > > backs the BGRT table to validate it against the requirements of the UEFI spec.
> > >
> > > Unfortunately, this causes problems on ARM, which does not permit
> > > early mappings to persist after paging_init() is called, resulting
> > > in a WARN() splat. Since we don't support the BGRT table on ARM anway,
> > > let's revert ARM to the old behaviour, which is to take down the
> > > early mapping at the end of efi_init().
> > >
> > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> > > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > > Cc: linux-efi@xxxxxxxxxxxxxxx
> > > Fixes: 3ea86495aef2 ("efi/arm: preserve early mapping of UEFI memory ...")
> >
> > This commit is only in v4.19 as far as I know. Does it even apply?
>
> This commit is in the following releases:
>         4.9.129 4.14.72 4.18.10 4.19
>
> so it should apply :)
>

Ah, of course.

I didn't realize (or failed to remember) that it had been taken into -stable.

Thanks,