[PATCH 4.19 33/46] mm: introduce mm_[p4d|pud|pmd]_folded

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 1071fc5779d9846fec56a4ff6089ab08cac1ab72 ]

Add three architecture overrideable functions to test if the
p4d, pud, or pmd layer of a page table is folded or not.

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 include/asm-generic/pgtable.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 88ebc6102c7c..15fd0277ffa6 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1127,4 +1127,20 @@ static inline bool arch_has_pfn_modify_check(void)
 #endif
 #endif
 
+/*
+ * On some architectures it depends on the mm if the p4d/pud or pmd
+ * layer of the page table hierarchy is folded or not.
+ */
+#ifndef mm_p4d_folded
+#define mm_p4d_folded(mm)	__is_defined(__PAGETABLE_P4D_FOLDED)
+#endif
+
+#ifndef mm_pud_folded
+#define mm_pud_folded(mm)	__is_defined(__PAGETABLE_PUD_FOLDED)
+#endif
+
+#ifndef mm_pmd_folded
+#define mm_pmd_folded(mm)	__is_defined(__PAGETABLE_PMD_FOLDED)
+#endif
+
 #endif /* _ASM_GENERIC_PGTABLE_H */
-- 
2.19.1