ea75a342ae
It's impossible to program a valid value for TRCCONFIGR.QE
when TRCIDR0.QSUPP==0b10. In that case the following is true:
Q element support is implemented, and only supports Q elements without
instruction counts. TRCCONFIGR.QE can only take the values 0b00 or 0b11.
Currently the low bit of QSUPP is checked to see if the low bit of QE can
be written to, but as you can see when QSUPP==0b10 the low bit is cleared
making it impossible to ever write the only valid value of 0b11 to QE.
0b10 would be written instead, which is a reserved QE value even for all
values of QSUPP.
The fix is to allow writing the low bit of QE for any non zero value of
QSUPP.
This change also ensures that the low bit is always set, even when the
user attempts to only set the high bit.
Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Fixes: d8c66962084f ("coresight-etm4x: Controls pertaining to the reset, mode, pe and events")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220120113047.2839622-2-james.clark@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
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.