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 /arch/arm64/Kconfig | |
| parent | bd35a4adc4131c530ec7d90242555eac7b3dbe3f (diff) | |
| download | linux-c852f320584600a372646055d8229e063949eee7.tar.bz2 | |
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deprecated in the ARMv7 architecture, superseded by ISB, DSB and DMB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 'arch/arm64/Kconfig')
| -rw-r--r-- | arch/arm64/Kconfig | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 2b6213840ec8..8e74dfe1e74d 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -201,6 +201,21 @@ config SWP_EMULATION If unsure, say Y +config CP15_BARRIER_EMULATION + bool "Emulate CP15 Barrier instructions" + help + The CP15 barrier instructions - CP15ISB, CP15DSB, and + CP15DMB - are deprecated in ARMv8 (and ARMv7). It is + strongly recommended to use the ISB, DSB, and DMB + instructions instead. + + Say Y here to enable software emulation of these + instructions for AArch32 userspace code. When this option is + enabled, CP15 barrier usage is traced which can help + identify software that needs updating. + + If unsure, say Y + endif endmenu |