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-rw-r--r--include/linux/pgtable.h44
1 files changed, 42 insertions, 2 deletions
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index a43047b1030d..e24d2c992b11 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -29,6 +29,24 @@
#endif
/*
+ * This defines the first usable user address. Platforms
+ * can override its value with custom FIRST_USER_ADDRESS
+ * defined in their respective <asm/pgtable.h>.
+ */
+#ifndef FIRST_USER_ADDRESS
+#define FIRST_USER_ADDRESS 0UL
+#endif
+
+/*
+ * This defines the generic helper for accessing PMD page
+ * table page. Although platforms can still override this
+ * via their respective <asm/pgtable.h>.
+ */
+#ifndef pmd_pgtable
+#define pmd_pgtable(pmd) pmd_page(pmd)
+#endif
+
+/*
* A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD]
*
* The pXx_index() functions return the index of the entry in the page
@@ -88,7 +106,7 @@ static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long address)
#ifndef pmd_offset
static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
- return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
+ return pud_pgtable(*pud) + pmd_index(address);
}
#define pmd_offset pmd_offset
#endif
@@ -96,7 +114,7 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
#ifndef pud_offset
static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address)
{
- return (pud_t *)p4d_page_vaddr(*p4d) + pud_index(address);
+ return p4d_pgtable(*p4d) + pud_index(address);
}
#define pud_offset pud_offset
#endif
@@ -1592,4 +1610,26 @@ typedef unsigned int pgtbl_mod_mask;
#define pte_leaf_size(x) PAGE_SIZE
#endif
+/*
+ * Some architectures have MMUs that are configurable or selectable at boot
+ * time. These lead to variable PTRS_PER_x. For statically allocated arrays it
+ * helps to have a static maximum value.
+ */
+
+#ifndef MAX_PTRS_PER_PTE
+#define MAX_PTRS_PER_PTE PTRS_PER_PTE
+#endif
+
+#ifndef MAX_PTRS_PER_PMD
+#define MAX_PTRS_PER_PMD PTRS_PER_PMD
+#endif
+
+#ifndef MAX_PTRS_PER_PUD
+#define MAX_PTRS_PER_PUD PTRS_PER_PUD
+#endif
+
+#ifndef MAX_PTRS_PER_P4D
+#define MAX_PTRS_PER_P4D PTRS_PER_P4D
+#endif
+
#endif /* _LINUX_PGTABLE_H */