--- zzzz-none-000/linux-3.10.107/Documentation/arm64/memory.txt	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/Documentation/arm64/memory.txt	2021-02-04 17:41:59.000000000 +0000
@@ -2,48 +2,59 @@
 		     ==============================
 
 Author: Catalin Marinas <catalin.marinas@arm.com>
-Date  : 20 February 2012
 
 This document describes the virtual memory layout used by the AArch64
 Linux kernel. The architecture allows up to 4 levels of translation
 tables with a 4KB page size and up to 3 levels with a 64KB page size.
 
-AArch64 Linux uses 3 levels of translation tables with the 4KB page
-configuration, allowing 39-bit (512GB) virtual addresses for both user
-and kernel. With 64KB pages, only 2 levels of translation tables are
-used but the memory layout is the same.
+AArch64 Linux uses either 3 levels or 4 levels of translation tables
+with the 4KB page configuration, allowing 39-bit (512GB) or 48-bit
+(256TB) virtual addresses, respectively, for both user and kernel. With
+64KB pages, only 2 levels of translation tables, allowing 42-bit (4TB)
+virtual address, are used but the memory layout is the same.
 
-User addresses have bits 63:39 set to 0 while the kernel addresses have
+User addresses have bits 63:48 set to 0 while the kernel addresses have
 the same bits set to 1. TTBRx selection is given by bit 63 of the
 virtual address. The swapper_pg_dir contains only kernel (global)
 mappings while the user pgd contains only user (non-global) mappings.
-The swapper_pgd_dir address is written to TTBR1 and never written to
+The swapper_pg_dir address is written to TTBR1 and never written to
 TTBR0.
 
 
-AArch64 Linux memory layout:
+AArch64 Linux memory layout with 4KB pages + 3 levels:
 
 Start			End			Size		Use
 -----------------------------------------------------------------------
 0000000000000000	0000007fffffffff	 512GB		user
+ffffff8000000000	ffffffffffffffff	 512GB		kernel
 
-ffffff8000000000	ffffffbbfffeffff	~240GB		vmalloc
 
-ffffffbbffff0000	ffffffbbffffffff	  64KB		[guard page]
+AArch64 Linux memory layout with 4KB pages + 4 levels:
 
-ffffffbc00000000	ffffffbdffffffff	   8GB		vmemmap
+Start			End			Size		Use
+-----------------------------------------------------------------------
+0000000000000000	0000ffffffffffff	 256TB		user
+ffff000000000000	ffffffffffffffff	 256TB		kernel
 
-ffffffbe00000000	ffffffbffbbfffff	  ~8GB		[guard, future vmmemap]
 
-ffffffbffbc00000	ffffffbffbdfffff	   2MB		earlyprintk device
+AArch64 Linux memory layout with 64KB pages + 2 levels:
 
-ffffffbffbe00000	ffffffbffbe0ffff	  64KB		PCI I/O space
+Start			End			Size		Use
+-----------------------------------------------------------------------
+0000000000000000	000003ffffffffff	   4TB		user
+fffffc0000000000	ffffffffffffffff	   4TB		kernel
 
-ffffffbbffff0000	ffffffbcffffffff	  ~2MB		[guard]
 
-ffffffbffc000000	ffffffbfffffffff	  64MB		modules
+AArch64 Linux memory layout with 64KB pages + 3 levels:
+
+Start			End			Size		Use
+-----------------------------------------------------------------------
+0000000000000000	0000ffffffffffff	 256TB		user
+ffff000000000000	ffffffffffffffff	 256TB		kernel
 
-ffffffc000000000	ffffffffffffffff	 256GB		kernel logical memory map
+
+For details of the virtual kernel memory layout please see the kernel
+booting log.
 
 
 Translation table lookup with 4KB pages:
@@ -57,7 +68,7 @@
  |                 |         |         |         +-> [20:12] L3 index
  |                 |         |         +-----------> [29:21] L2 index
  |                 |         +---------------------> [38:30] L1 index
- |                 +-------------------------------> [47:39] L0 index (not used)
+ |                 +-------------------------------> [47:39] L0 index
  +-------------------------------------------------> [63] TTBR0/1
 
 
@@ -70,6 +81,14 @@
  |                 |    |               |              v
  |                 |    |               |            [15:0]  in-page offset
  |                 |    |               +----------> [28:16] L3 index
- |                 |    +--------------------------> [41:29] L2 index (only 38:29 used)
- |                 +-------------------------------> [47:42] L1 index (not used)
+ |                 |    +--------------------------> [41:29] L2 index
+ |                 +-------------------------------> [47:42] L1 index
  +-------------------------------------------------> [63] TTBR0/1
+
+
+When using KVM, the hypervisor maps kernel pages in EL2, at a fixed
+offset from the kernel VA (top 24bits of the kernel VA set to zero):
+
+Start			End			Size		Use
+-----------------------------------------------------------------------
+0000004000000000	0000007fffffffff	 256GB		kernel objects mapped in HYP