ARM: mm: HugeTLB support for LPAE systems.

[firefly-linux-kernel-4.4.55.git] / arch / arm / include / asm / pgtable-3level.h

diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 86b8fe398b9514d89a9032658f6bb3ad221b069e..d1bcd8226cb102dbedd26f8f48a16153649d0e91 100644 (file)
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -61,6 +61,14 @@
 
 #define USER_PTRS_PER_PGD      (PAGE_OFFSET / PGDIR_SIZE)
 
+/*
+ * Hugetlb definitions.
+ */
+#define HPAGE_SHIFT            PMD_SHIFT
+#define HPAGE_SIZE             (_AC(1, UL) << HPAGE_SHIFT)
+#define HPAGE_MASK             (~(HPAGE_SIZE - 1))
+#define HUGETLB_PAGE_ORDER     (HPAGE_SHIFT - PAGE_SHIFT)
+
 /*
  * "Linux" PTE definitions for LPAE.
  *
@@ -166,8 +174,28 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
                clean_pmd_entry(pmdp);  \
        } while (0)
 
+/*
+ * For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes
+ * that are written to a page table but not for ptes created with mk_pte.
+ *
+ * In hugetlb_no_page, a new huge pte (new_pte) is generated and passed to
+ * hugetlb_cow, where it is compared with an entry in a page table.
+ * This comparison test fails erroneously leading ultimately to a memory leak.
+ *
+ * To correct this behaviour, we mask off PTE_EXT_NG for any pte that is
+ * present before running the comparison.
+ */
+#define __HAVE_ARCH_PTE_SAME
+#define pte_same(pte_a,pte_b)  ((pte_present(pte_a) ? pte_val(pte_a) & ~PTE_EXT_NG     \
+                                       : pte_val(pte_a))                               \
+                               == (pte_present(pte_b) ? pte_val(pte_b) & ~PTE_EXT_NG   \
+                                       : pte_val(pte_b)))
+
 #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,__pte(pte_val(pte)|(ext)))
 
+#define pte_huge(pte)          (pte_val(pte) && !(pte_val(pte) & PTE_TABLE_BIT))
+#define pte_mkhuge(pte)                (__pte(pte_val(pte) & ~PTE_TABLE_BIT))
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_PGTABLE_3LEVEL_H */