[PATCH 5.6 112/126] sparc32: fix page table traversal in srmmu_nocache_init()

From: Greg Kroah-Hartman
Date: Tue May 26 2020 - 15:16:04 EST

From: Mike Rapoport <rppt@xxxxxxxxxxxxx>

commit 0cfc8a8d70dcd51db783e8e87917e02149c71458 upstream.

The srmmu_nocache_init() uses __nocache_fix() macro to add an offset to
page table entry to access srmmu_nocache_pool.

But since sparc32 has only three actual page table levels, pgd, p4d and
pud are essentially the same thing and pgd_offset() and p4d_offset() are
no-ops, the __nocache_fix() should be done only at PUD level.

Remove __nocache_fix() for p4d_offset() and pud_offset() and keep it
only for PUD and lower levels.

Fixes: c2bc26f7ca1f ("sparc32: use PUD rather than PGD to get PMD in srmmu_nocache_init()")
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Anatoly Pugachev <matorola@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/sparc/mm/srmmu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -331,8 +331,8 @@ static void __init srmmu_nocache_init(vo

while (vaddr < srmmu_nocache_end) {
pgd = pgd_offset_k(vaddr);
- p4d = p4d_offset(__nocache_fix(pgd), vaddr);
- pud = pud_offset(__nocache_fix(p4d), vaddr);
+ p4d = p4d_offset(pgd, vaddr);
+ pud = pud_offset(p4d, vaddr);
pmd = pmd_offset(__nocache_fix(pud), vaddr);
pte = pte_offset_kernel(__nocache_fix(pmd), vaddr);