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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: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Jungseok Lee <jungseoklee85@gmail.com>
hifive-unleashed-5.1
Catalin Marinas 2014-07-21 15:54:50 +01:00
parent 7078db4621
commit 383c279911
4 changed files with 22 additions and 9 deletions
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8
Documentation/arm64/memory.txt
View File

@ -45,6 +45,14 @@ Start End Size Use
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
booting log.

1
arch/arm64/Kconfig
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@ -210,6 +210,7 @@ config ARM64_VA_BITS
config ARM64_PGTABLE_LEVELS
int
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 4 if ARM64_4K_PAGES && ARM64_VA_BITS_48

16
arch/arm64/include/asm/page.h
View File

@ -34,17 +34,19 @@
/*
* 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)
* map the kernel. The swapper also maps the FDT (see __create_page_tables for
* more information).
* map the kernel. With the 64K page configuration, swapper and idmap need to
* map to pte level. The swapper also maps the FDT (see __create_page_tables
* for more information).
*/
#if CONFIG_ARM64_PGTABLE_LEVELS == 4
#define SWAPPER_DIR_SIZE (3 * PAGE_SIZE)
#define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
#ifdef CONFIG_ARM64_64K_PAGES
#define SWAPPER_PGTABLE_LEVELS (CONFIG_ARM64_PGTABLE_LEVELS)
#else
#define SWAPPER_DIR_SIZE (2 * PAGE_SIZE)
#define IDMAP_DIR_SIZE (2 * PAGE_SIZE)
#define SWAPPER_PGTABLE_LEVELS (CONFIG_ARM64_PGTABLE_LEVELS - 1)
#endif
#define SWAPPER_DIR_SIZE (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
#define IDMAP_DIR_SIZE (SWAPPER_DIR_SIZE)
#ifndef __ASSEMBLY__
#include <asm/pgtable-types.h>

6
arch/arm64/kernel/head.S
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@ -55,9 +55,11 @@
#ifdef CONFIG_ARM64_64K_PAGES
#define BLOCK_SHIFT PAGE_SHIFT
#define BLOCK_SIZE PAGE_SIZE
#define TABLE_SHIFT PMD_SHIFT
#else
#define BLOCK_SHIFT SECTION_SHIFT
#define BLOCK_SIZE SECTION_SIZE
#define TABLE_SHIFT PUD_SHIFT
#endif
#define KERNEL_START KERNEL_RAM_VADDR
@ -505,8 +507,8 @@ ENDPROC(__calc_phys_offset)
*/
.macro create_pgd_entry, tbl, virt, tmp1, tmp2
create_table_entry \tbl, \virt, PGDIR_SHIFT, PTRS_PER_PGD, \tmp1, \tmp2
#if CONFIG_ARM64_PGTABLE_LEVELS == 4
create_table_entry \tbl, \virt, PUD_SHIFT, PTRS_PER_PUD, \tmp1, \tmp2
#if SWAPPER_PGTABLE_LEVELS == 3
create_table_entry \tbl, \virt, TABLE_SHIFT, PTRS_PER_PTE, \tmp1, \tmp2
#endif
.endm