UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity
OpenCloudOS-Kernel/arch/powerpc/platforms/powernv/subcore.h

26 lines
857 B
C
Raw Normal View History

powerpc/powernv: Add support for POWER8 split core on powernv Upcoming POWER8 chips support a concept called split core. This is where the core can be split into subcores that although not full cores, are able to appear as full cores to a guest. The splitting & unsplitting procedure is mildly complicated, and explained at length in the comments within the patch. One notable detail is that when splitting or unsplitting we need to pull offline cpus out of their offline state to do work as part of the procedure. The interface for changing the split mode is via a sysfs file, eg: $ echo 2 > /sys/devices/system/cpu/subcores_per_core Currently supported values are '1', '2' and '4'. And indicate respectively that the core should be unsplit, split in half, and split in quarters. These modes correspond to threads_per_subcore of 8, 4 and 2. We do not allow changing the split mode while KVM VMs are active. This is to prevent the value changing while userspace is configuring the VM, and also to prevent the mode being changed in such a way that existing guests are unable to be run. CPU hotplug fixes by Srivatsa. max_cpus fixes by Mahesh. cpuset fixes by benh. Fix for irq race by paulus. The rest by mikey and mpe. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-05-23 16:15:30 +08:00
/*
* Copyright 2013, Michael Ellerman, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
/* These are ordered and tested with <= */
#define SYNC_STEP_INITIAL 0
#define SYNC_STEP_UNSPLIT 1 /* Set by secondary when it sees unsplit */
#define SYNC_STEP_REAL_MODE 2 /* Set by secondary when in real mode */
#define SYNC_STEP_FINISHED 3 /* Set by secondary when split/unsplit is done */
#ifndef __ASSEMBLY__
powernv/powerpc: Add winkle support for offline cpus Winkle is a deep idle state supported in power8 chips. A core enters winkle when all the threads of the core enter winkle. In this state power supply to the entire chiplet i.e core, private L2 and private L3 is turned off. As a result it gives higher powersavings compared to sleep. But entering winkle results in a total hypervisor state loss. Hence the hypervisor context has to be preserved before entering winkle and restored upon wake up. Power-on Reset Engine (PORE) is a dedicated engine which is responsible for powering on the chiplet during wake up. It can be programmed to restore the register contests of a few specific registers. This patch uses PORE to restore register state wherever possible and uses stack to save and restore rest of the necessary registers. With hypervisor state restore things fall under three categories- per-core state, per-subcore state and per-thread state. To manage this, extend the infrastructure introduced for sleep. Mainly we add a paca variable subcore_sibling_mask. Using this and the core_idle_state we can distingush first thread in core and subcore. Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-10 02:56:53 +08:00
#ifdef CONFIG_SMP
powerpc/powernv: Add support for POWER8 split core on powernv Upcoming POWER8 chips support a concept called split core. This is where the core can be split into subcores that although not full cores, are able to appear as full cores to a guest. The splitting & unsplitting procedure is mildly complicated, and explained at length in the comments within the patch. One notable detail is that when splitting or unsplitting we need to pull offline cpus out of their offline state to do work as part of the procedure. The interface for changing the split mode is via a sysfs file, eg: $ echo 2 > /sys/devices/system/cpu/subcores_per_core Currently supported values are '1', '2' and '4'. And indicate respectively that the core should be unsplit, split in half, and split in quarters. These modes correspond to threads_per_subcore of 8, 4 and 2. We do not allow changing the split mode while KVM VMs are active. This is to prevent the value changing while userspace is configuring the VM, and also to prevent the mode being changed in such a way that existing guests are unable to be run. CPU hotplug fixes by Srivatsa. max_cpus fixes by Mahesh. cpuset fixes by benh. Fix for irq race by paulus. The rest by mikey and mpe. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-05-23 16:15:30 +08:00
void split_core_secondary_loop(u8 *state);
powernv/powerpc: Add winkle support for offline cpus Winkle is a deep idle state supported in power8 chips. A core enters winkle when all the threads of the core enter winkle. In this state power supply to the entire chiplet i.e core, private L2 and private L3 is turned off. As a result it gives higher powersavings compared to sleep. But entering winkle results in a total hypervisor state loss. Hence the hypervisor context has to be preserved before entering winkle and restored upon wake up. Power-on Reset Engine (PORE) is a dedicated engine which is responsible for powering on the chiplet during wake up. It can be programmed to restore the register contests of a few specific registers. This patch uses PORE to restore register state wherever possible and uses stack to save and restore rest of the necessary registers. With hypervisor state restore things fall under three categories- per-core state, per-subcore state and per-thread state. To manage this, extend the infrastructure introduced for sleep. Mainly we add a paca variable subcore_sibling_mask. Using this and the core_idle_state we can distingush first thread in core and subcore. Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-10 02:56:53 +08:00
extern void update_subcore_sibling_mask(void);
#else
static inline void update_subcore_sibling_mask(void) { };
#endif /* CONFIG_SMP */
#endif /* __ASSEMBLY__ */