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| author |   Steve Capper <steve.capper@arm.com> | 2018-12-06 22:50:37 +0000 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2018-12-10 18:42:17 +0000 |
| commit | 363524d2b12270d86677e1154ecc1c5061f43219 (patch) | |
| tree | 1b4653ee1c9509e7233e8d3a75a2f8cb8c66f62b /drivers/firmware/efi/libstub | |
| parent | mm: mmap: Allow for "high" userspace addresses (diff) | |
| download | linux-dev-363524d2b12270d86677e1154ecc1c5061f43219.tar.xz linux-dev-363524d2b12270d86677e1154ecc1c5061f43219.zip | |
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 'drivers/firmware/efi/libstub')
| -rw-r--r-- | drivers/firmware/efi/libstub/arm-stub.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 3d36142cf812..6640942a1c0d 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -33,7 +33,7 @@ #define EFI_RT_VIRTUAL_SIZE SZ_512M #ifdef CONFIG_ARM64 -# define EFI_RT_VIRTUAL_LIMIT TASK_SIZE_64 +# define EFI_RT_VIRTUAL_LIMIT DEFAULT_MAP_WINDOW_64 #else # define EFI_RT_VIRTUAL_LIMIT TASK_SIZE #endif |