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| author | Steve Capper <steve.capper@arm.com> | 2018-12-07 01:50:37 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2018-12-10 21:42:17 +0300 |
| commit | 363524d2b12270d86677e1154ecc1c5061f43219 (patch) | |
| tree | 1b4653ee1c9509e7233e8d3a75a2f8cb8c66f62b /arch/arm64/include/asm/processor.h | |
| parent | f6795053dac8d4d2f90d4a98842dd6d2ccd544ad (diff) | |
| download | linux-363524d2b12270d86677e1154ecc1c5061f43219.tar.xz | |
arm64: mm: Introduce DEFAULT_MAP_WINDOW
We wish to introduce a 52-bit virtual address space for userspace but
maintain compatibility with software that assumes the maximum VA space
size is 48 bit.
In order to achieve this, on 52-bit VA systems, we make mmap behave as
if it were running on a 48-bit VA system (unless userspace explicitly
requests a VA where addr[51:48] != 0).
On a system running a 52-bit userspace we need TASK_SIZE to represent
the 52-bit limit as it is used in various places to distinguish between
kernelspace and userspace addresses.
Thus we need a new limit for mmap, stack, ELF loader and EFI (which uses
TTBR0) to represent the non-extended VA space.
This patch introduces DEFAULT_MAP_WINDOW and DEFAULT_MAP_WINDOW_64 and
switches the appropriate logic to use that instead of TASK_SIZE.
Signed-off-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/processor.h')
| -rw-r--r-- | arch/arm64/include/asm/processor.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 6b0d4dff5012..102bab4344b7 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -53,19 +53,25 @@ * TASK_SIZE - the maximum size of a user space task. * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area. */ + +#define DEFAULT_MAP_WINDOW_64 (UL(1) << VA_BITS) + #ifdef CONFIG_COMPAT #define TASK_SIZE_32 UL(0x100000000) #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) +#define DEFAULT_MAP_WINDOW (test_thread_flag(TIF_32BIT) ? \ + TASK_SIZE_32 : DEFAULT_MAP_WINDOW_64) #else #define TASK_SIZE TASK_SIZE_64 +#define DEFAULT_MAP_WINDOW DEFAULT_MAP_WINDOW_64 #endif /* CONFIG_COMPAT */ -#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 4)) +#define TASK_UNMAPPED_BASE (PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4)) +#define STACK_TOP_MAX DEFAULT_MAP_WINDOW_64 -#define STACK_TOP_MAX TASK_SIZE_64 #ifdef CONFIG_COMPAT #define AARCH32_VECTORS_BASE 0xffff0000 #define STACK_TOP (test_thread_flag(TIF_32BIT) ? \ |