@@ -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.
@@ -199,7 +199,6 @@ config ARM64_VA_BITS_42
config ARM64_VA_BITS_48
bool "48-bit"
depends on !KVM
- depends on ARM64_4K_PAGES
endchoice
@@ -212,6 +211,7 @@ 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
@@ -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>
@@ -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
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> --- Some minor clean-up and 64K page configuration can use 48-bit VA space. Documentation/arm64/memory.txt | 8 ++++++++ arch/arm64/Kconfig | 2 +- arch/arm64/include/asm/page.h | 16 +++++++++------- arch/arm64/kernel/head.S | 6 ++++-- 4 files changed, 22 insertions(+), 10 deletions(-)