[PATCH] ARM: fix early early_iounmap()

[Ard Biesheuvel]

On Thu, 4 Nov 2021 at 01:46, Michał Mirosław <mirq-linux at rere.qmqm.pl> wrote:
>
> Currently __set_fixmap() bails out with a warning when called in early boot
> from early_iounmap(). Fix it, and while at it, make the comment a bit easier
> to understand.
>
> Cc: <stable at vger.kernel.org>
> Fixes: b089c31c519c ("ARM: 8667/3: Fix memory attribute inconsistencies when using fixmap")
> Signed-off-by: Michał Mirosław <mirq-linux at rere.qmqm.pl>

Acked-by: Ard Biesheuvel <ardb at 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_START);
>         BUG_ON(idx >= __end_of_fixed_addresses);
>
> -       /* we only support device mappings until pgprot_kernel has been set */
> +       /* We support only device mappings before pgprot_kernel is set. */
>         if (WARN_ON(pgprot_val(prot) != pgprot_val(FIXMAP_PAGE_IO) &&
> -                   pgprot_val(pgprot_kernel) == 0))
> +                   pgprot_val(prot) && pgprot_val(pgprot_kernel) == 0))
>                 return;
>
>         if (pgprot_val(prot))
> --
> 2.30.2
>