4.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Will Deacon <will.dea...@arm.com>
Commit 4e6020565596 upstream.
Break-before-make is not needed when transitioning from Global to
Non-Global mappings, provided that the contiguous hint is not being used.
Signed-off-by: Will Deacon <will.dea...@arm.com>
Signed-off-by: Catalin Marinas <catalin.mari...@arm.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/arm64/mm/mmu.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -117,6 +117,10 @@ static bool pgattr_change_is_safe(u64 ol
if ((old | new) & PTE_CONT)
return false;
+ /* Transitioning from Global to Non-Global is safe */
+ if (((old ^ new) == PTE_NG) && (new & PTE_NG))
+ return true;
+
return ((old ^ new) & ~mask) == 0;
}
