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| author | Steve Capper <steve.capper@arm.com> | 2018-12-06 22:50:42 +0000 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2018-12-10 18:42:18 +0000 |
| commit | b9567720a1b8e739380e0241413606c056c57859 (patch) | |
| tree | 760f658f0fbb3ec46f0cbdaa0314245f6f094fb7 /arch/arm64/include/asm/elf.h | |
| parent | 67e7fdfcc6824a4f768d76d89377b33baad58fad (diff) | |
| download | lwn-b9567720a1b8e739380e0241413606c056c57859.tar.gz lwn-b9567720a1b8e739380e0241413606c056c57859.zip | |
arm64: mm: Allow forcing all userspace addresses to 52-bit
On arm64 52-bit VAs are provided to userspace when a hint is supplied to
mmap. This helps maintain compatibility with software that expects at
most 48-bit VAs to be returned.
In order to help identify software that has 48-bit VA assumptions, this
patch allows one to compile a kernel where 52-bit VAs are returned by
default on HW that supports it.
This feature is intended to be for development systems only.
Signed-off-by: Steve Capper <steve.capper@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/elf.h')
| -rw-r--r-- | arch/arm64/include/asm/elf.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index bc9bd9e77d9d..6adc1a90e7e6 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -117,7 +117,11 @@ * 64-bit, this is above 4GB to leave the entire 32-bit address * space open for things that want to use the area for 32-bit pointers. */ +#ifdef CONFIG_ARM64_FORCE_52BIT +#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) +#else #define ELF_ET_DYN_BASE (2 * DEFAULT_MAP_WINDOW_64 / 3) +#endif /* CONFIG_ARM64_FORCE_52BIT */ #ifndef __ASSEMBLY__ |