Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
b9866bb168
coresight_enable_path() enables the components in a trace path from a given source to a sink, excluding the source. The operation is performed in the reverse order; the sink first and then backwards in the list. However, if we encounter an error in enabling any of the component, we simply disable all the components in the given path irrespective of whether we enabled some of the components in the enable iteration. This could interfere with another trace session if one of the link devices is turned off (e.g, TMC-ETF). So, we need to make sure that we only disable those components which were actually enabled from the iteration. This patch achieves the same by refactoring the coresight_disable_path to accept a "node" to start from in the forward order, which can then be used from the error path of coresight_enable_path(). With this change, we don't issue a disable call back for a component which didn't get enabled. This change of behavior triggers a bug in coresight_enable_link(), where we leave the refcount on the device and will prevent the device from being enabled forever. So, we also drop the refcount in the coresight_enable_link() if the operation failed. Also, with the refactoring, we always start after the first node (which is the "SOURCE" device) for disabling the entire path. This implies, we must not find a "SOURCE" in the middle of the path. Hence, added a WARN_ON() to make sure the paths we get are sane, rather than simply ignoring them. Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| README | ||
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.