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bb5f23ae16
[ Upstream commit 64eb04ae545294e105ad91714dc3167a0b660731 ]
According to the software usage PKLXF in Arm ARM (ARM DDI 0487 L.a), a
Context synchronization event is required before enabling the trace
unit.
An ISB is added to meet this requirement, particularly for guarding the
operations in the flow:
etm4x_allow_trace()
`> kvm_tracing_set_el1_configuration()
`> write_sysreg_s(trfcr_while_in_guest, SYS_TRFCR_EL12)
Improved the barrier comments to provide more accurate information.
Fixes: 1ab3bb9df5 ("coresight: etm4x: Add necessary synchronization for sysreg access")
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Yeoreun Yun <yeoreum.yun@arm.com>
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251111-arm_coresight_power_management_fix-v6-5-f55553b6c8b3@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.