Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fix from Will Deacon:
"Fix pte_same() to avoid getting stuck on write fault.
This single arm64 fix is a revert of 747a70e60b72 ("arm64: Fix
copy-on-write referencing in HugeTLB"), not because that patch was
wrong, but because it was broken by aa57157be69f ("arm64: Ensure
VM_WRITE|VM_SHARED ptes are clean by default") which we merged in
-rc6.
We spotted the issue in Android (AOSP), where one of the JIT threads
gets stuck on a write fault during boot because the faulting pte is
marked as PTE_DIRTY | PTE_WRITE | PTE_RDONLY and the fault handler
decides that there's nothing to do thanks to pte_same() masking out
PTE_RDONLY.
Thanks to John Stultz for reporting this and testing this so quickly,
and to Steve Capper for confirming that the HugeTLB tests continue to
pass"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Do not mask out PTE_RDONLY in pte_same()
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 8330810..565aa45 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -283,23 +283,6 @@
set_pte(ptep, pte);
}
-#define __HAVE_ARCH_PTE_SAME
-static inline int pte_same(pte_t pte_a, pte_t pte_b)
-{
- pteval_t lhs, rhs;
-
- lhs = pte_val(pte_a);
- rhs = pte_val(pte_b);
-
- if (pte_present(pte_a))
- lhs &= ~PTE_RDONLY;
-
- if (pte_present(pte_b))
- rhs &= ~PTE_RDONLY;
-
- return (lhs == rhs);
-}
-
/*
* Huge pte definitions.
*/
