diff options
| author | Punit Agrawal <punit.agrawal@arm.com> | 2014-11-18 11:41:26 +0000 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2014-11-20 16:34:48 +0000 |
| commit | c852f320584600a372646055d8229e063949eee7 (patch) | |
| tree | 57f88ee08e59727db2ac8d305ad89f15990b4ecd /Documentation/arm64 | |
| parent | bd35a4adc4131c530ec7d90242555eac7b3dbe3f (diff) | |
| download | lwn-c852f320584600a372646055d8229e063949eee7.tar.gz lwn-c852f320584600a372646055d8229e063949eee7.zip | |
arm64: Emulate CP15 Barrier instructions
The CP15 barrier instructions (CP15ISB, CP15DSB and CP15DMB) are
deprecated in the ARMv7 architecture, superseded by ISB, DSB and DMB
instructions respectively. Some implementations may provide the
ability to disable the CP15 barriers by disabling the CP15BEN bit in
SCTLR_EL1. If not enabled, the encodings for these instructions become
undefined.
To support legacy software using these instructions, this patch
register hooks to -
* emulate CP15 barriers and warn the user about their use
* toggle CP15BEN in SCTLR_EL1
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'Documentation/arm64')
| -rw-r--r-- | Documentation/arm64/legacy_instructions.txt | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/arm64/legacy_instructions.txt b/Documentation/arm64/legacy_instructions.txt index 5ab58614b7ed..a3b3da2ec6ed 100644 --- a/Documentation/arm64/legacy_instructions.txt +++ b/Documentation/arm64/legacy_instructions.txt @@ -38,3 +38,8 @@ Supported legacy instructions Node: /proc/sys/abi/swp Status: Obsolete Default: Undef (0) + +* CP15 Barriers +Node: /proc/sys/abi/cp15_barrier +Status: Deprecated +Default: Emulate (1) |