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Gautham R. Shenoy
17ed4c8f81
POWER9 DD1.0 hardware has a bug where the SPRs of a thread waking up from stop 0,1,2 with ESL=1 can endup being misplaced in the core. Thus the HSPRG0 of a thread waking up from can contain the paca pointer of its sibling. This patch implements a context recovery framework within threads of a core, by provisioning space in paca_struct for saving every sibling threads's paca pointers. Basically, we should be able to arrive at the right paca pointer from any of the thread's existing paca pointer. At bootup, during powernv idle-init, we save the paca address of every CPU in each one its siblings paca_struct in the slot corresponding to this CPU's index in the core. On wakeup from a stop, the thread will determine its index in the core from the TIR register and recover its PACA pointer by indexing into the correct slot in the provisioned space in the current PACA. Furthermore, ensure that the NVGPRs are restored from the stack on the way out by setting the NAPSTATELOST in paca. [Changelog written with inputs from svaidy@linux.vnet.ibm.com] Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Call it a bug] 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.