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Commit 383c2799 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

arm64: Add support for 48-bit VA space with 64KB page configuration 



This patch allows support for 3 levels of page tables with 64KB page
configuration allowing 48-bit VA space. The pgd is no longer a full
PAGE_SIZE (PTRS_PER_PGD is 64) and (swapper|idmap)_pg_dir are not fully
populated (pgd_alloc falls back to kzalloc).

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Tested-by: default avatarJungseok Lee <jungseoklee85@gmail.com>
parent 7078db46

Documentation/arm64/memory.txt

+8 −0
Original line number Original line Diff line number Diff line
@@ -45,6 +45,14 @@ Start End Size Use 
fffffc0000000000	ffffffffffffffff	   4TB		kernel

fffffc0000000000	ffffffffffffffff	   4TB		kernel









AArch64 Linux memory layout with 64KB pages + 3 levels:



Start			End			Size		Use

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

0000000000000000	0000ffffffffffff	 256TB		user

ffff000000000000	ffffffffffffffff	 256TB		kernel





For details of the virtual kernel memory layout please see the kernel

For details of the virtual kernel memory layout please see the kernel

booting log.

booting log.

arch/arm64/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -210,6 +210,7 @@ config ARM64_VA_BITS 
config ARM64_PGTABLE_LEVELS

config ARM64_PGTABLE_LEVELS

	int

	int

	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42

	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42

	default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48

	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39

	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39

	default 4 if ARM64_4K_PAGES && ARM64_VA_BITS_48

	default 4 if ARM64_4K_PAGES && ARM64_VA_BITS_48

arch/arm64/include/asm/page.h

+9 −7
Original line number Original line Diff line number Diff line
@@ -34,17 +34,19 @@ 
/*

/*

 * The idmap and swapper page tables need some space reserved in the kernel

 * The idmap and swapper page tables need some space reserved in the kernel

 * image. Both require pgd, pud (4 levels only) and pmd tables to (section)

 * image. Both require pgd, pud (4 levels only) and pmd tables to (section)

 * map the kernel. The swapper also maps the FDT (see __create_page_tables for

 * map the kernel. With the 64K page configuration, swapper and idmap need to

 * more information).

 * map to pte level. The swapper also maps the FDT (see __create_page_tables

 * for more information).

 */

 */

#if CONFIG_ARM64_PGTABLE_LEVELS == 4

#ifdef CONFIG_ARM64_64K_PAGES

#define SWAPPER_DIR_SIZE	(3 * PAGE_SIZE)

#define SWAPPER_PGTABLE_LEVELS	(CONFIG_ARM64_PGTABLE_LEVELS)

#define IDMAP_DIR_SIZE		(3 * PAGE_SIZE)

#else

#else

#define SWAPPER_DIR_SIZE	(2 * PAGE_SIZE)

#define SWAPPER_PGTABLE_LEVELS	(CONFIG_ARM64_PGTABLE_LEVELS - 1)

#define IDMAP_DIR_SIZE		(2 * PAGE_SIZE)

#endif

#endif





#define SWAPPER_DIR_SIZE	(SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)

#define IDMAP_DIR_SIZE		(SWAPPER_DIR_SIZE)



#ifndef __ASSEMBLY__

#ifndef __ASSEMBLY__





#include <asm/pgtable-types.h>

#include <asm/pgtable-types.h>

arch/arm64/kernel/head.S

+4 −2
Original line number Original line Diff line number Diff line
@@ -55,9 +55,11 @@ 
#ifdef CONFIG_ARM64_64K_PAGES

#ifdef CONFIG_ARM64_64K_PAGES

#define BLOCK_SHIFT	PAGE_SHIFT

#define BLOCK_SHIFT	PAGE_SHIFT

#define BLOCK_SIZE	PAGE_SIZE

#define BLOCK_SIZE	PAGE_SIZE

#define TABLE_SHIFT	PMD_SHIFT

#else

#else

#define BLOCK_SHIFT	SECTION_SHIFT

#define BLOCK_SHIFT	SECTION_SHIFT

#define BLOCK_SIZE	SECTION_SIZE

#define BLOCK_SIZE	SECTION_SIZE

#define TABLE_SHIFT	PUD_SHIFT

#endif

#endif





#define KERNEL_START	KERNEL_RAM_VADDR

#define KERNEL_START	KERNEL_RAM_VADDR
@@ -505,8 +507,8 @@ ENDPROC(__calc_phys_offset) 
 */

 */

	.macro	create_pgd_entry, tbl, virt, tmp1, tmp2

	.macro	create_pgd_entry, tbl, virt, tmp1, tmp2

	create_table_entry \tbl, \virt, PGDIR_SHIFT, PTRS_PER_PGD, \tmp1, \tmp2

	create_table_entry \tbl, \virt, PGDIR_SHIFT, PTRS_PER_PGD, \tmp1, \tmp2

#if CONFIG_ARM64_PGTABLE_LEVELS == 4

#if SWAPPER_PGTABLE_LEVELS == 3

	create_table_entry \tbl, \virt, PUD_SHIFT, PTRS_PER_PUD, \tmp1, \tmp2

	create_table_entry \tbl, \virt, TABLE_SHIFT, PTRS_PER_PTE, \tmp1, \tmp2

#endif

#endif

	.endm

	.endm