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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Thu, 4 Nov 2021 10:07:36 +0100
Message-ID: <CAMj1kXEsm1oK5uPqku7uJfF=FeKx1fEjTu80czZPguQPBO_z2w@mail.gmail.com>
Subject: Re: [PATCH] ARM: fix early early_iounmap()
To:     =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= <mirq-linux@rere.qmqm.pl>
Cc:     Jon Medhurst <tixy@linaro.org>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, 4 Nov 2021 at 01:46, Micha=C5=82 Miros=C5=82aw <mirq-linux@rere.qmq=
m.pl> wrote:
>
> Currently __set_fixmap() bails out with a warning when called in early bo=
ot
> from early_iounmap(). Fix it, and while at it, make the comment a bit eas=
ier
> to understand.
>
> Cc: <stable@vger.kernel.org>
> Fixes: b089c31c519c ("ARM: 8667/3: Fix memory attribute inconsistencies w=
hen using fixmap")
> Signed-off-by: Micha=C5=82 Miros=C5=82aw <mirq-linux@rere.qmqm.pl>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  arch/arm/mm/mmu.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index a4e006005107..274e4f73fd33 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -390,9 +390,9 @@ void __set_fixmap(enum fixed_addresses idx, phys_addr=
_t phys, pgprot_t prot)
>         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) < FIXADDR_ST=
ART);
>         BUG_ON(idx >=3D __end_of_fixed_addresses);
>
> -       /* we only support device mappings until pgprot_kernel has been s=
et */
> +       /* We support only device mappings before pgprot_kernel is set. *=
/
>         if (WARN_ON(pgprot_val(prot) !=3D pgprot_val(FIXMAP_PAGE_IO) &&
> -                   pgprot_val(pgprot_kernel) =3D=3D 0))
> +                   pgprot_val(prot) && pgprot_val(pgprot_kernel) =3D=3D =
0))
>                 return;
>
>         if (pgprot_val(prot))
> --
> 2.30.2
>