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This works around a hardware bug in "Nimbus" POWER9 DD2.2 processors, where a treclaim performed in fake suspend mode can cause subsequent reads from the XER register to return inconsistent values for the SO (summary overflow) bit. The inconsistent SO bit state can potentially be observed on any thread in the core. We have to do the treclaim because that is the only way to get the thread out of suspend state (fake or real) and into non-transactional state. The workaround for the bug is to force the core into SMT4 mode before doing the treclaim. This patch adds the code to do that, conditional on the CPU_FTR_P9_TM_XER_SO_BUG feature bit. Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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.