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| author | Robin Murphy <robin.murphy@arm.com> | 2018-02-05 16:34:18 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2018-02-06 23:53:32 +0100 |
| commit | 51369e398d0d33e8f524314e672b07e8cf870e79 (patch) | |
| tree | 9a30fc16dfef70bdc8547ef696ba6be7fa273c87 /arch/arm64/kernel | |
| parent | arm64: Implement array_index_mask_nospec() (diff) | |
| download | linux-51369e398d0d33e8f524314e672b07e8cf870e79.tar.xz linux-51369e398d0d33e8f524314e672b07e8cf870e79.zip | |
arm64: Make USER_DS an inclusive limit
Currently, USER_DS represents an exclusive limit while KERNEL_DS is
inclusive. In order to do some clever trickery for speculation-safe
masking, we need them both to behave equivalently - there aren't enough
bits to make KERNEL_DS exclusive, so we have precisely one option. This
also happens to correct a longstanding false negative for a range
ending on the very top byte of kernel memory.
Mark Rutland points out that we've actually got the semantics of
addresses vs. segments muddled up in most of the places we need to
amend, so shuffle the {USER,KERNEL}_DS definitions around such that we
can correct those properly instead of just pasting "-1"s everywhere.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 9b8635d9d7ae..17c15f741780 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -167,10 +167,10 @@ alternative_else_nop_endif .else add x21, sp, #S_FRAME_SIZE get_thread_info tsk - /* Save the task's original addr_limit and set USER_DS (TASK_SIZE_64) */ + /* Save the task's original addr_limit and set USER_DS */ ldr x20, [tsk, #TSK_TI_ADDR_LIMIT] str x20, [sp, #S_ORIG_ADDR_LIMIT] - mov x20, #TASK_SIZE_64 + mov x20, #USER_DS str x20, [tsk, #TSK_TI_ADDR_LIMIT] /* No need to reset PSTATE.UAO, hardware's already set it to 0 for us */ .endif /* \el == 0 */ |