4.15-stable review patch. If anyone has any objections, please let me know.
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From: Will Deacon will.deacon@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.deacon@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@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; }