Let's use bit 1, which should be irrelevant if the PTE is marked invalid
eiher way -- we really only care about bit 0.
Note that one alternative would be using one of the type bits: core-mm only
supports 5 bits, so there is no need to reserve space for 6.
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
arch/arm64/include/asm/pgtable-prot.h | 1 +
arch/arm64/include/asm/pgtable.h | 19 ++++++++++++++++++-
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index b1e1b74d993c..fd6ddf14c190 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -14,6 +14,7 @@
* Software defined PTE bits definition.
*/
#define PTE_WRITE (PTE_DBM) /* same as DBM (51) */
+#define PTE_SWP_EXCLUSIVE (PTE_TABLE_BIT) /* only for swp ptes */
#define PTE_DIRTY (_AT(pteval_t, 1) << 55)
#define PTE_SPECIAL (_AT(pteval_t, 1) << 56)
#define PTE_DEVMAP (_AT(pteval_t, 1) << 57)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 94e147e5456c..c78994073cd0 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -402,6 +402,22 @@ static inline pgprot_t mk_pmd_sect_prot(pgprot_t prot)
return __pgprot((pgprot_val(prot) & ~PMD_TABLE_BIT) | PMD_TYPE_SECT);
}
+#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
+static inline pte_t pte_swp_mkexclusive(pte_t pte)
+{
+ return set_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE));
+}
+
+static inline int pte_swp_exclusive(pte_t pte)
+{
+ return pte_val(pte) & PTE_SWP_EXCLUSIVE;
+}
+
+static inline pte_t pte_swp_clear_exclusive(pte_t pte)
+{
+ return clear_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE));
+}
+
#ifdef CONFIG_NUMA_BALANCING
/*
* See the comment in include/linux/pgtable.h
@@ -908,7 +924,8 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
/*
* Encode and decode a swap entry:
- * bits 0-1: present (must be zero)
+ * bits 0: present (must be zero)
+ * bits 1: remember PG_anon_exclusive
* bits 2-7: swap type
* bits 8-57: swap offset
* bit 58: PTE_PROT_NONE (must be zero)
--
2.35.1
--
Thanks,
David / dhildenb
