mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 04:34:11 +08:00
Mainline Linux tree for various devices, only for fun :)
9006123157
Currently, the powernv cpu-offline function assumes that platform idle states such as stop on POWER9, winkle/sleep/nap on POWER8 are always available. On POWER8, it picks nap as the default state if other deep idle states like sleep/winkle are not available and enabled in the platform. On POWER9, nap is not available and all idle states are managed by STOP instruction. The parameters to the idle state are passed through processor stop status control register (PSSCR). Hence as such executing STOP would take parameters from current PSSCR. We do not want to make any assumptions in kernel on what STOP states and PSSCR features are configured by the platform. Ideally platform will configure a good set of stop states that can be used in the kernel. We would like to start with a clean slate, if the platform choose to not configure any state or there is an error in platform firmware that lead to no stop states being configured or allowed to be requested. This patch adds a fallback method for CPU-Hotplug that is similar to snooze loop at idle where the threads are left to spin at low priority and hence reduce the cycles consumed. This is a safe fallback mechanism in the case when no stop state would be requested if the platform firmware did not configure them most likely due to an error condition. Requesting a stop state when the platform has not configured them or enabled them would lead to further error conditions which could be difficult to debug. [Changelog written with inputs from svaidy@linux.vnet.ibm.com] Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.