[PATCH 5.10 539/575] ARM: 9155/1: fix early early_iounmap()

[Greg Kroah-Hartman]

From: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>

commit 0d08e7bf0d0d1a29aff7b16ef516f7415eb1aa05 upstream.

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@xxxxxxxxxxxxxxx>
Fixes: b089c31c519c ("ARM: 8667/3: Fix memory attribute inconsistencies when using fixmap")
Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm/mm/mmu.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -391,9 +391,9 @@ void __set_fixmap(enum fixed_addresses i
 		     FIXADDR_END);
 	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))