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authorPunit Agrawal <punit.agrawal@arm.com>2014-11-18 11:41:26 +0000
committerDavid Brown <david.brown@linaro.org>2015-12-03 16:53:45 -0800
commitd25673ceb72d0aca589a488d99af1dd2fcd22640 (patch)
tree392c5e14c9a18710559c7bab74a0a1ddb022e5e1 /Documentation
parent9d11f6fa5cc87425cda2a0dcd1edecc433560afc (diff)
downloadlinux-linaro-stable-d25673ceb72d0aca589a488d99af1dd2fcd22640.tar.gz
arm64: Emulate CP15 Barrier instructions
commit c852f320584600a372646055d8229e063949eee7 upstream. The CP15 barrier instructions (CP15ISB, CP15DSB and CP15DMB) are deprecated in the ARMv7 architecture, superseded by ISB, DSB and DMB instructions respectively.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> Signed-off-by: David Brown <david.brown@linaro.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/arm64/legacy_instructions.txt5
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Status: Obsolete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)