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abf16336dd
Add a handler of CPU_SUSPEND host PSCI SMCs. The SMC can either enter a sleep state indistinguishable from a WFI or a deeper sleep state that behaves like a CPU_OFF+CPU_ON except that the core is still considered online while asleep. The handler saves r0,pc of the host and makes the same call to EL3 with the hyp CPU entry point. It either returns back to the handler and then back to the host, or wakes up into the entry point and initializes EL2 state before dropping back to EL1. No EL2 state needs to be saved/restored for this purpose. CPU_ON and CPU_SUSPEND are both implemented using struct psci_boot_args to store the state upon powerup, with each CPU having separate structs for CPU_ON and CPU_SUSPEND so that CPU_SUSPEND can operate locklessly and so that a CPU_ON call targeting a CPU cannot interfere with a concurrent CPU_SUSPEND call on that CPU. Signed-off-by: David Brazdil <dbrazdil@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201202184122.26046-23-dbrazdil@google.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.