[PATCH] arm64: add lookup_address()

[Tycho Andersen]

Similarly to x86, let's add lookup_address() and use it in
kernel_page_present(). We'll use it in the next patch for the
implementation of XPFO as well.

Signed-off-by: Tycho Andersen <tycho@xxxxxxxxxx>
---
 arch/arm64/include/asm/pgtable-types.h |  2 ++
 arch/arm64/mm/pageattr.c               | 47 ++++++++++++++++++++--------------
 include/xen/arm/page.h                 | 10 --------
 3 files changed, 30 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable-types.h b/arch/arm64/include/asm/pgtable-types.h
index 345a072b5856..fad3db5a673f 100644
--- a/arch/arm64/include/asm/pgtable-types.h
+++ b/arch/arm64/include/asm/pgtable-types.h
@@ -64,4 +64,6 @@ typedef struct { pteval_t pgprot; } pgprot_t;
 #include <asm-generic/5level-fixup.h>
 #endif
 
+extern pte_t *lookup_address(unsigned long addr, unsigned int *level);
+
 #endif	/* __ASM_PGTABLE_TYPES_H */
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index a682a0a2a0fa..437a12485873 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -138,6 +138,32 @@ int set_memory_valid(unsigned long addr, int numpages, int enable)
 					__pgprot(PTE_VALID));
 }
 
+pte_t *lookup_address(unsigned long addr, unsigned int *level)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	if (unlikely(level)) {
+		WARN(1, "level unused on arm64\n");
+		*level = 0;
+	}
+
+	pgd = pgd_offset_k(addr);
+	if (pgd_none(*pgd))
+		return NULL;
+
+	pud = pud_offset(pgd, addr);
+	if (pud_none(*pud))
+		return NULL;
+
+	pmd = pmd_offset(pud, addr);
+	if (pmd_none(*pmd))
+		return NULL;
+
+	return pte_offset_kernel(pmd, addr);
+}
+
 #ifdef CONFIG_DEBUG_PAGEALLOC
 void __kernel_map_pages(struct page *page, int numpages, int enable)
 {
@@ -156,29 +182,12 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
  */
 bool kernel_page_present(struct page *page)
 {
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
 	unsigned long addr = (unsigned long)page_address(page);
+	pte_t *pte = lookup_address(addr);
 
-	pgd = pgd_offset_k(addr);
-	if (pgd_none(*pgd))
-		return false;
-
-	pud = pud_offset(pgd, addr);
-	if (pud_none(*pud))
-		return false;
-	if (pud_sect(*pud))
-		return true;
-
-	pmd = pmd_offset(pud, addr);
-	if (pmd_none(*pmd))
+	if (!pte)
 		return false;
-	if (pmd_sect(*pmd))
-		return true;
 
-	pte = pte_offset_kernel(pmd, addr);
 	return pte_valid(*pte);
 }
 #endif /* CONFIG_HIBERNATION */
diff --git a/include/xen/arm/page.h b/include/xen/arm/page.h
index 415dbc6e43fd..6adc2a955340 100644
--- a/include/xen/arm/page.h
+++ b/include/xen/arm/page.h
@@ -84,16 +84,6 @@ static inline xmaddr_t arbitrary_virt_to_machine(void *vaddr)
 	BUG();
 }
 
-/* TODO: this shouldn't be here but it is because the frontend drivers
- * are using it (its rolled in headers) even though we won't hit the code path.
- * So for right now just punt with this.
- */
-static inline pte_t *lookup_address(unsigned long address, unsigned int *level)
-{
-	BUG();
-	return NULL;
-}
-
 extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 				   struct gnttab_map_grant_ref *kmap_ops,
 				   struct page **pages, unsigned int count);
-- 
2.11.0