kernel/linux.git/arch/arc/include/asm/spinlock.h, branch v6.18.21

ARC: [plat-eznps]: Drop support for EZChip NPS platform

2020-10-06T04:02:29+00:00

NPS customers are no longer doing active development, as evident from rand config build failures reported in recent times, so drop support for NPS platform. Tested-by: kernel test robot Signed-off-by: Vineet Gupta

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

ARCv2: spinlock: remove the extra smp_mb before lock, after unlock

2019-03-08T19:17:49+00:00

- ARCv2 LLSC spinlocks have smp_mb() both before and after the LLSC instructions, which is not required per lkmm ACQ/REL semantics. smp_mb() is only needed _after_ lock and _before_ unlock. So remove the extra barriers. The reason they were there was mainly historical. At the time of initial SMP Linux bringup on HS38 cores, I was too conservative, given the fluidity of both hw and sw. The last attempt to ditch the extra barrier showed some hackbench regression which is apparently not the case now (atleast for LLSC case, read on...) - EX based spinlocks (!CONFIG_ARC_HAS_LLSC) still needs the extra smp_mb(), not due to lkmm, but due to some hardware shenanigans. W/o that, hackbench triggers RCU stall splat so extra DMB is retained !LLSC based systems are not realistic Linux sstem anyways so they can afford to be a nit suboptimal ;-) | [ARCLinux]# for i in (seq 1 1 5) ; do hackbench; done | Running with 10 groups 400 process | INFO: task hackbench:158 blocked for more than 10 seconds. | Not tainted 4.20.0-00005-g96b18288a88e-dirty #117 | "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. | hackbench D 0 158 135 0x00000000 | | Stack Trace: | watchdog: BUG: soft lockup - CPU#3 stuck for 59s! [hackbench:469] | Modules linked in: | Path: (null) | CPU: 3 PID: 469 Comm: hackbench Not tainted 4.20.0-00005-g96b18288a88e-dirty | | [ECR ]: 0x00000000 => Check Programmer's Manual | [EFA ]: 0x00000000 | [BLINK ]: do_exit+0x4a6/0x7d0 | [ERET ]: _raw_write_unlock_irq+0x44/0x5c - And while at it, remove the extar smp_mb() from EX based arch_read_trylock() since the spin lock there guarantees a full barrier anyways - For LLSC case, hackbench threads improves with this patch (HAPS @ 50MHz) ---- before ---- | | [ARCLinux]# for i in 1 2 3 4 5; do hackbench 10 thread; done | Running with 10 groups 400 threads | Time: 16.253 | Time: 16.445 | Time: 16.590 | Time: 16.721 | Time: 16.544 ---- after ---- | | [ARCLinux]# for i in 1 2 3 4 5; do hackbench 10 thread; done | Running with 10 groups 400 threads | Time: 15.638 | Time: 15.730 | Time: 15.870 | Time: 15.842 | Time: 15.729 Acked-by: Peter Zijlstra (Intel) Signed-off-by: Vineet Gupta

locking/arch: Remove dummy arch_{read,spin,write}_lock_flags() implementations

2017-10-10T09:50:19+00:00

The arch_{read,spin,write}_lock_flags() macros are simply mapped to the non-flags versions by the majority of architectures, so do this in core code and remove the dummy implementations. Also remove the implementation in spinlock_up.h, since all callers of do_raw_spin_lock_flags() call local_irq_save(flags) anyway. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1507055129-12300-4-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar

locking/arch: Remove dummy arch_{read,spin,write}_relax() implementations

2017-10-10T09:50:18+00:00

arch_{read,spin,write}_relax() are defined as cpu_relax() by the core code, so architectures that can't do better (i.e. most of them) don't need to bother with the dummy definitions. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1507055129-12300-3-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar

locking/core: Remove {read,spin,write}_can_lock()

2017-10-10T09:50:18+00:00

Outside of the locking code itself, {read,spin,write}_can_lock() have no users in tree. Apparmor (the last remaining user of write_can_lock()) got moved over to lockdep by the previous patch. This patch removes the use of {read,spin,write}_can_lock() from the BUILD_LOCK_OPS macro, deferring to the trylock operation for testing the lock status, and subsequently removes the unused macros altogether. They aren't guaranteed to work in a concurrent environment and can give incorrect results in the case of qrwlock. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1507055129-12300-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar

Merge tag 'arc-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

2017-09-08T23:02:18+00:00

Pull ARC updates from Vineet Gupta: - Support for HSDK board hosting a Quad core HS38x4 based SoC running @1GHz (and some prerrquisite changes such as ability to scoot the kernel code/data from start of memory map etc) - Quite a few updates for EZChip (Mellanox) platform - Fixes to fault/exception printing * tag 'arc-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (26 commits) ARC: Re-enable MMU upon Machine Check exception ARC: Show fault information passed to show_kernel_fault_diag() ARC: [plat-hsdk] initial port for HSDK board ARC: mm: Decouple RAM base address from kernel link address ARCv2: IOC: Tighten up the contraints (specifically base / size alignment) ARC: [plat-axs103] refactor the DT fudging code ARC: [plat-axs103] use clk driver #2: Add core pll node to DT to manage cpu clk ARC: [plat-axs103] use clk driver #1: Get rid of platform specific cpu clk setting ARCv2: SLC: provide a line based flush routine for debugging ARC: Hardcode ARCH_DMA_MINALIGN to max line length we may have ARC: [plat-eznps] handle extra aux regs #2: kernel/entry exit ARC: [plat-eznps] handle extra aux regs #1: save/restore on context switch ARC: [plat-eznps] avoid toggling of DPC register ARC: [plat-eznps] Update the init sequence of aux regs per cpu. ARC: [plat-eznps] new command line argument for HW scheduler at MTM ARC: set boot print log level to PR_INFO ARC: [plat-eznps] Handle user memory error same in simulation and silicon ARC: [plat-eznps] use schd.wft instruction instead of sleep at idle task ARC: create cpu specific version of arch_cpu_idle() ARC: [plat-eznps] spinlock aware for MTM ...

ARC: [plat-eznps] spinlock aware for MTM

2017-08-28T22:17:36+00:00

This way when we execute "ex" during trying to hold lock we can switch to other HW thread and utilize the core intead of just spinning on a lock. We noticed about 10% improvement of execution time with hackbench test. Signed-off-by: Noam Camus Signed-off-by: Vineet Gupta

ARC: spinlock: Document the EX based spin_unlock

2017-08-28T22:17:36+00:00

Signed-off-by: Vineet Gupta

arch: Remove spin_unlock_wait() arch-specific definitions

2017-08-17T15:08:59+00:00

There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore removes the underlying arch-specific arch_spin_unlock_wait() for all architectures providing them. Signed-off-by: Paul E. McKenney Cc: Cc: Peter Zijlstra Cc: Alan Stern Cc: Andrea Parri Cc: Linus Torvalds Acked-by: Will Deacon Acked-by: Boqun Feng