linux-kernel - [tip:x86/pti] x86/mm: Map cpu_entry_area at the same place on 4/5 level

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Message-ID: <tip-f2078904810373211fb15f91888fba14c01a4acc@git.kernel.org>
Date:   Thu, 4 Jan 2018 14:10:20 -0800
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, dave.hansen@...ux.intel.com, luto@...nel.org,
        kuleshovmail@...il.com, benjamin.gilbert@...eos.com,
        stable@...r.kernel.org, hpa@...or.com, gregkh@...uxfoundation.org,
        tglx@...utronix.de, linux-kernel@...r.kernel.org,
        peterz@...radead.org
Subject: [tip:x86/pti] x86/mm: Map cpu_entry_area at the same place on 4/5
 level

Commit-ID:  f2078904810373211fb15f91888fba14c01a4acc
Gitweb:     https://git.kernel.org/tip/f2078904810373211fb15f91888fba14c01a4acc
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Thu, 4 Jan 2018 13:01:40 +0100
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 4 Jan 2018 23:04:57 +0100

x86/mm: Map cpu_entry_area at the same place on 4/5 level

There is no reason for 4 and 5 level pagetables to have a different
layout. It just makes determining vaddr_end for KASLR harder than
necessary.

Fixes: 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the fixmap")
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Benjamin Gilbert <benjamin.gilbert@...eos.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: stable <stable@...r.kernel.org>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Garnier <thgarnie@...gle.com>,
Cc: Alexander Kuleshov <kuleshovmail@...il.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801041320360.1771@nanos

---
 Documentation/x86/x86_64/mm.txt         | 7 ++++---
 arch/x86/include/asm/pgtable_64_types.h | 4 ++--
 arch/x86/mm/dump_pagetables.c           | 2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index ddd5ffd..f7dabe1 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -12,8 +12,8 @@ ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
 ... unused hole ...
 ffffec0000000000 - fffffbffffffffff (=44 bits) kasan shadow memory (16TB)
 ... unused hole ...
-fffffe0000000000 - fffffe7fffffffff (=39 bits) LDT remap for PTI
-fffffe8000000000 - fffffeffffffffff (=39 bits) cpu_entry_area mapping
+fffffe0000000000 - fffffe7fffffffff (=39 bits) cpu_entry_area mapping
+fffffe8000000000 - fffffeffffffffff (=39 bits) LDT remap for PTI
 ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
 ... unused hole ...
 ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space
@@ -37,7 +37,8 @@ ffd4000000000000 - ffd5ffffffffffff (=49 bits) virtual memory map (512TB)
 ... unused hole ...
 ffdf000000000000 - fffffc0000000000 (=53 bits) kasan shadow memory (8PB)
 ... unused hole ...
-fffffe8000000000 - fffffeffffffffff (=39 bits) cpu_entry_area mapping
+fffffe0000000000 - fffffe7fffffffff (=39 bits) cpu_entry_area mapping
+... unused hole ...
 ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
 ... unused hole ...
 ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 6233e55..61b4b60 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -88,7 +88,7 @@ typedef struct { pteval_t pte; } pte_t;
 # define VMALLOC_SIZE_TB	_AC(32, UL)
 # define __VMALLOC_BASE		_AC(0xffffc90000000000, UL)
 # define __VMEMMAP_BASE		_AC(0xffffea0000000000, UL)
-# define LDT_PGD_ENTRY		_AC(-4, UL)
+# define LDT_PGD_ENTRY		_AC(-3, UL)
 # define LDT_BASE_ADDR		(LDT_PGD_ENTRY << PGDIR_SHIFT)
 #endif
 
@@ -110,7 +110,7 @@ typedef struct { pteval_t pte; } pte_t;
 #define ESPFIX_PGD_ENTRY	_AC(-2, UL)
 #define ESPFIX_BASE_ADDR	(ESPFIX_PGD_ENTRY << P4D_SHIFT)
 
-#define CPU_ENTRY_AREA_PGD	_AC(-3, UL)
+#define CPU_ENTRY_AREA_PGD	_AC(-4, UL)
 #define CPU_ENTRY_AREA_BASE	(CPU_ENTRY_AREA_PGD << P4D_SHIFT)
 
 #define EFI_VA_START		( -4 * (_AC(1, UL) << 30))
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index f56902c..2a4849e 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -61,10 +61,10 @@ enum address_markers_idx {
 	KASAN_SHADOW_START_NR,
 	KASAN_SHADOW_END_NR,
 #endif
+	CPU_ENTRY_AREA_NR,
 #if defined(CONFIG_MODIFY_LDT_SYSCALL) && !defined(CONFIG_X86_5LEVEL)
 	LDT_NR,
 #endif
-	CPU_ENTRY_AREA_NR,
 #ifdef CONFIG_X86_ESPFIX64
 	ESPFIX_START_NR,
 #endif