From 847264fb7e73ade5b5e4b6eea3daa243a1f5217e Mon Sep 17 00:00:00 2001 From: Catalin Marinas <catalin.marinas@arm.com> Date: Wed, 23 Oct 2013 16:50:07 +0100 Subject: [PATCH] arm64: Use 42-bit address space with 64K pages This patch expands the VA_BITS to 42 when the 64K page configuration is enabled allowing 2TB kernel linear mapping. Linux still uses 2 levels of page tables in this configuration with pgd now being a full page. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> --- Documentation/arm64/memory.txt | 27 ++++++++++++++++++- arch/arm64/include/asm/memory.h | 11 +++++--- arch/arm64/include/asm/pgtable-2level-hwdef.h | 4 +-- arch/arm64/include/asm/pgtable.h | 2 +- 4 files changed, 37 insertions(+), 7 deletions(-) diff --git a/Documentation/arm64/memory.txt b/Documentation/arm64/memory.txt index f28899d5c83e..5e054bfe4dde 100644 --- a/Documentation/arm64/memory.txt +++ b/Documentation/arm64/memory.txt @@ -21,7 +21,7 @@ The swapper_pgd_dir address is written to TTBR1 and never written to TTBR0. -AArch64 Linux memory layout: +AArch64 Linux memory layout with 4KB pages: Start End Size Use ----------------------------------------------------------------------- @@ -46,6 +46,31 @@ ffffffbffc000000 ffffffbfffffffff 64MB modules ffffffc000000000 ffffffffffffffff 256GB kernel logical memory map +AArch64 Linux memory layout with 64KB pages: + +Start End Size Use +----------------------------------------------------------------------- +0000000000000000 000003ffffffffff 4TB user + +fffffc0000000000 fffffdfbfffeffff ~2TB vmalloc + +fffffdfbffff0000 fffffdfbffffffff 64KB [guard page] + +fffffdfc00000000 fffffdfdffffffff 8GB vmemmap + +fffffdfe00000000 fffffdfffbbfffff ~8GB [guard, future vmmemap] + +fffffdfffbc00000 fffffdfffbdfffff 2MB earlyprintk device + +fffffdfffbe00000 fffffdfffbe0ffff 64KB PCI I/O space + +fffffdfffbe10000 fffffdfffbffffff ~2MB [guard] + +fffffdfffc000000 fffffdffffffffff 64MB modules + +fffffe0000000000 ffffffffffffffff 2TB kernel logical memory map + + Translation table lookup with 4KB pages: +--------+--------+--------+--------+--------+--------+--------+--------+ diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 20925bcf4e2a..37762175896f 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -33,18 +33,23 @@ #define UL(x) _AC(x, UL) /* - * PAGE_OFFSET - the virtual address of the start of the kernel image. + * PAGE_OFFSET - the virtual address of the start of the kernel image (top + * (VA_BITS - 1)) * VA_BITS - the maximum number of bits for virtual addresses. * TASK_SIZE - the maximum size of a user space task. * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area. * The module space lives between the addresses given by TASK_SIZE * and PAGE_OFFSET - it must be within 128MB of the kernel text. */ -#define PAGE_OFFSET UL(0xffffffc000000000) +#ifdef CONFIG_ARM64_64K_PAGES +#define VA_BITS (42) +#else +#define VA_BITS (39) +#endif +#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1)) #define MODULES_END (PAGE_OFFSET) #define MODULES_VADDR (MODULES_END - SZ_64M) #define EARLYCON_IOBASE (MODULES_VADDR - SZ_4M) -#define VA_BITS (39) #define TASK_SIZE_64 (UL(1) << VA_BITS) #ifdef CONFIG_COMPAT diff --git a/arch/arm64/include/asm/pgtable-2level-hwdef.h b/arch/arm64/include/asm/pgtable-2level-hwdef.h index 0a8ed3f94e93..2593b490c56a 100644 --- a/arch/arm64/include/asm/pgtable-2level-hwdef.h +++ b/arch/arm64/include/asm/pgtable-2level-hwdef.h @@ -21,10 +21,10 @@ * 8192 entries of 8 bytes each, occupying a 64KB page. Levels 0 and 1 are not * used. The 2nd level table (PGD for Linux) can cover a range of 4TB, each * entry representing 512MB. The user and kernel address spaces are limited to - * 512GB and therefore we only use 1024 entries in the PGD. + * 4TB in the 64KB page configuration. */ #define PTRS_PER_PTE 8192 -#define PTRS_PER_PGD 1024 +#define PTRS_PER_PGD 8192 /* * PGDIR_SHIFT determines the size a top-level page table entry can map. diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index f0bebc5e22cd..17bd3af0a117 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -33,7 +33,7 @@ /* * VMALLOC and SPARSEMEM_VMEMMAP ranges. */ -#define VMALLOC_START UL(0xffffff8000000000) +#define VMALLOC_START (UL(0xffffffffffffffff) << VA_BITS) #define VMALLOC_END (PAGE_OFFSET - UL(0x400000000) - SZ_64K) #define vmemmap ((struct page *)(VMALLOC_END + SZ_64K)) -- GitLab