[tip:x86/mm] generic/pgtable: Introduce {p4d,pgd}_same()

[tip-bot for Dan Williams]

Commit-ID:  0cebbb60f759a709dabb3c87b9704f9844878850
Gitweb:     https://git.kernel.org/tip/0cebbb60f759a709dabb3c87b9704f9844878850
Author:     Dan Williams <dan.j.williams@xxxxxxxxx>
AuthorDate: Tue, 4 Dec 2018 13:37:11 -0800
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 5 Dec 2018 09:03:06 +0100

generic/pgtable: Introduce {p4d,pgd}_same()

In preparation for introducing '_safe' versions of page table entry 'set'
helpers, introduce generic versions of p4d_same() and pgd_same().

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/154395943153.32119.1733586547359626311.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/asm-generic/pgtable.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index eea50ef8b8cd..dae7f98babed 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -386,6 +386,20 @@ static inline int pud_same(pud_t pud_a, pud_t pud_b)
 }
 #endif
 
+#ifndef __HAVE_ARCH_P4D_SAME
+static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b)
+{
+	return p4d_val(p4d_a) == p4d_val(p4d_b);
+}
+#endif
+
+#ifndef __HAVE_ARCH_PGD_SAME
+static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
+{
+	return pgd_val(pgd_a) == pgd_val(pgd_b);
+}
+#endif
+
 #ifndef __HAVE_ARCH_DO_SWAP_PAGE
 /*
  * Some architectures support metadata associated with a page. When a