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* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/debug.h> We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/debug.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* ARC: [plat-eznps] Use dedicated identity auxiliary register.Noam Camus2016-05-091-0/+13
| | | | | | | | With generic "identity" num of CPUs is limited to 256 (8 bit). We use our alternative AUX register GLOBAL_ID (12 bit). Now we can support up to 4096 CPUs. Signed-off-by: Noam Camus <noamc@ezchip.com>
* ARC: remove SYNC from __switch_to()Vineet Gupta2015-11-171-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | SYNC in __switch_to() is a historic relic and not needed at all. - In UP context it is obviously useless, why would we want to stall the core for all updates to stack memory of t0 to complete before loading kernel mode callee registers from t1 stack's memory. - In SMP, there could be potential race in which outgoing task could be concurrently picked for running on a different core, thus writes to stack here need to be visible before the reads from stack on other core. Peter confirmed that generic schedular already has needed barriers (by way of rq lock) so there is no need for additional arch barrier. This came up when Noam was trying to replace this SYNC with EZChip specific hardware thread scheduling instruction for their platform support. Link: http://lkml.kernel.org/r/20151102092654.GM17308@twins.programming.kicks-ass.net Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Cc: Noam Camus <noamc@ezchip.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: [SMP] Fix build failures for large NR_CPUSVineet Gupta2013-11-061-1/+12
| | | | | | | | | | | | | | | ST.as only takes S9 (255) for offset. This was going out of range when accessing a task_struct field with 4k NR_CPUS (due to 128b of coumaks itself in there). Workaround by using an intermediate register to do the address scaling. There is some duplication of fix for ctx_sw.c and ctx_sw_asm.S however given that C version will go away soon I'm not bothering to factor out the common code. Reported-by: Noam Camus <noamc@ezchip.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: pt_regs update #3: Remove unused gutter at start of callee_regsVineet Gupta2013-06-221-9/+5
| | | | | | | | | | | | | | | | This is trickier than prev two: * context switching code saves kernel mode callee regs in the format of struct callee_regs thus needs adjustment. This also reduces the height of topmost kernel stack frame by 1 word. * Since kernel stack unwinder is sensitive to height of topmost kernel stack frame, that needs a word of adjustment too. ptrace needs a bit of updating since pt_regs now diverges from user_regs_struct. Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: SMP supportVineet Gupta2013-02-151-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ARC common code to enable a SMP system + ISS provided SMP extensions. ARC700 natively lacks SMP support, hence some of the core features are are only enabled if SoCs have the necessary h/w pixie-dust. This includes: -Inter Processor Interrupts (IPI) -Cache coherency -load-locked/store-conditional ... The low level exception handling would be completely broken in SMP because we don't have hardware assisted stack switching. Thus a fair bit of this code is repurposing the MMU_SCRATCH reg for event handler prologues to keep them re-entrant. Many thanks to Rajeshwar Ranga for his initial "major" contributions to SMP Port (back in 2008), and to Noam Camus and Gilad Ben-Yossef for help with resurrecting that in 3.2 kernel (2012). Note that this platform code is again singleton design pattern - so multiple SMP platforms won't build at the moment - this deficiency is addressed in subsequent patches within this series. Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Rajeshwar Ranga <rajeshwar.ranga@gmail.com> Cc: Noam Camus <noamc@ezchip.com> Cc: Gilad Ben-Yossef <gilad@benyossef.com>
* ARC: [optim] Cache "current" in Register r25Vineet Gupta2013-02-151-0/+7
| | | | Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: Process-creation/scheduling/idle-loopVineet Gupta2013-02-111-0/+91
Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de>