From b83ce5ee91471d19c403ff91227204fb37c95fb2 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 14 Feb 2018 14:16:48 +0300 Subject: [PATCH] x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52 __PHYSICAL_MASK_SHIFT is used to define the mask that helps to extract physical address from a page table entry. Although real physical address space available may differ between machines, it's safe to use 52 as __PHYSICAL_MASK_SHIFT. Unused bits above log2(MAXPHYADDR) up to bit 51 are reserved and must be 0. Signed-off-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180214111656.88514-2-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/page_64_types.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h index e1407312c412..f68e6526891d 100644 --- a/arch/x86/include/asm/page_64_types.h +++ b/arch/x86/include/asm/page_64_types.h @@ -52,11 +52,12 @@ #define __START_KERNEL_map _AC(0xffffffff80000000, UL) /* See Documentation/x86/x86_64/mm.txt for a description of the memory map. */ -#ifdef CONFIG_X86_5LEVEL + #define __PHYSICAL_MASK_SHIFT 52 + +#ifdef CONFIG_X86_5LEVEL #define __VIRTUAL_MASK_SHIFT 56 #else -#define __PHYSICAL_MASK_SHIFT 46 #define __VIRTUAL_MASK_SHIFT 47 #endif -- 2.11.0