From: Peter Zijlstra <peterz@infradead.org>
To: Stafford Horne <shorne@gmail.com>
Cc: Jonas Bonn <jonas@southpole.se>,
Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
linux@roeck-us.net, openrisc@lists.librecores.org,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH v3 10/25] openrisc: add spinlock implementation
Date: Wed, 22 Feb 2017 12:37:09 +0100 [thread overview]
Message-ID: <20170222113709.GP6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <9ec913b47790e9412d5b71a5fc52794ce4ebafb9.1487702890.git.shorne@gmail.com>
On Wed, Feb 22, 2017 at 04:11:39AM +0900, Stafford Horne wrote:
> +static inline int arch_spin_trylock(arch_spinlock_t *lock)
> +{
> + unsigned long contended, tmp;
> + u32 slock;
> +
> + /* contended = (lock->tickets.owner != lock->tickets.next) */
> + __asm__ __volatile__(
> + "1: l.lwa %0, 0(%3) \n"
> + " l.srli %1, %0, 16 \n"
> + " l.andi %2, %0, 0xffff \n"
> + " l.sfeq %1, %2 \n"
> + " l.bnf 1f \n"
> + " l.ori %1, r0, 1 \n"
> + " l.add %0, %0, %4 \n"
> + " l.swa 0(%3), %0 \n"
> + " l.bnf 1b \n"
> + " l.ori %1, r0, 0 \n"
#ifdef CONFIG_SMP
" l.sync \n"
#endif
> + "1: \n"
> + : "=&r" (slock), "=&r" (contended), "=&r" (tmp)
> + : "r" (&lock->slock), "r" (1 << TICKET_SHIFT)
> + : "cc", "memory");
> +
Then s/contended/acquired/, flip the bitset in the asm, and replace the
entire thing below with:
return acquired;
> + if (!contended) {
> + smp_mb();
> + return 1;
> + } else {
> + return 0;
> + }
> +}
next prev parent reply other threads:[~2017-02-22 11:37 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-21 19:11 [PATCH v3 00/25] OpenRISC patches for 4.11 final call Stafford Horne
2017-02-21 19:11 ` [PATCH v3 01/25] openrisc: use SPARSE_IRQ Stafford Horne
2017-02-21 19:11 ` [PATCH v3 02/25] openrisc: add cache way information to cpuinfo Stafford Horne
2017-03-14 12:08 ` Sudeep Holla
2017-03-14 13:11 ` Stefan Kristiansson
2017-03-14 13:45 ` Sudeep Holla
2017-03-14 14:09 ` Stafford Horne
2017-03-14 15:55 ` Sudeep Holla
2017-02-21 19:11 ` [PATCH v3 03/25] openrisc: tlb miss handler optimizations Stafford Horne
2017-02-21 19:11 ` [PATCH v3 04/25] openrisc: head: use THREAD_SIZE instead of magic constant Stafford Horne
2017-02-21 19:11 ` [PATCH v3 05/25] openrisc: head: refactor out tlb flush into it's own function Stafford Horne
2017-02-21 19:11 ` [PATCH v3 06/25] openrisc: add l.lwa/l.swa emulation Stafford Horne
2017-02-21 19:11 ` [PATCH v3 07/25] openrisc: add atomic bitops Stafford Horne
2017-02-21 19:11 ` [PATCH v3 08/25] openrisc: add cmpxchg and xchg implementations Stafford Horne
2017-02-22 11:19 ` Peter Zijlstra
2017-02-22 14:20 ` Stafford Horne
2017-02-22 17:30 ` [OpenRISC] " Richard Henderson
2017-02-22 22:43 ` Stafford Horne
2017-02-21 19:11 ` [PATCH v3 09/25] openrisc: add optimized atomic operations Stafford Horne
2017-02-22 11:27 ` Peter Zijlstra
2017-02-22 14:22 ` Stafford Horne
2017-02-22 17:31 ` [OpenRISC] " Richard Henderson
2017-02-22 22:42 ` Stafford Horne
2017-02-21 19:11 ` [PATCH v3 10/25] openrisc: add spinlock implementation Stafford Horne
2017-02-22 11:29 ` Peter Zijlstra
2017-02-22 11:32 ` Peter Zijlstra
2017-02-22 11:37 ` Peter Zijlstra [this message]
2017-02-22 12:02 ` Peter Zijlstra
2017-02-22 11:38 ` Peter Zijlstra
2017-02-22 11:41 ` Peter Zijlstra
2017-02-22 12:08 ` Peter Zijlstra
2017-02-21 19:11 ` [PATCH v3 11/25] openrisc: add futex_atomic_* implementations Stafford Horne
2017-02-21 19:11 ` [PATCH v3 12/25] openrisc: remove unnecessary stddef.h include Stafford Horne
2017-02-21 19:11 ` [PATCH v3 13/25] openrisc: Fix the bitmask for the unit present register Stafford Horne
2017-02-21 19:11 ` [PATCH v3 14/25] openrisc: Initial support for the idle state Stafford Horne
2017-02-21 20:24 ` Joe Perches
2017-02-22 14:19 ` Stafford Horne
2017-02-21 19:11 ` [PATCH v3 15/25] openrisc: Add optimized memset Stafford Horne
2017-02-21 19:11 ` [PATCH v3 16/25] openrisc: Add optimized memcpy routine Stafford Horne
2017-02-21 19:11 ` [PATCH v3 17/25] openrisc: Add .gitignore Stafford Horne
2017-02-21 19:11 ` [PATCH v3 18/25] MAINTAINERS: Add the openrisc official repository Stafford Horne
2017-02-21 19:11 ` [PATCH v3 19/25] scripts/checkstack.pl: Add openrisc support Stafford Horne
2017-02-21 19:11 ` [PATCH v3 20/25] openrisc: entry: Whitespace and comment cleanups Stafford Horne
2017-02-21 19:11 ` [PATCH v3 21/25] openrisc: entry: Fix delay slot detection Stafford Horne
2017-02-21 19:11 ` [PATCH v3 22/25] openrisc: head: Move init strings to rodata section Stafford Horne
2017-02-21 19:11 ` [PATCH v3 23/25] arch/openrisc/lib/memcpy.c: use correct OR1200 option Stafford Horne
2017-02-21 19:11 ` [PATCH v3 24/25] openrisc: Export ioremap symbols used by modules Stafford Horne
2017-02-21 19:11 ` [PATCH v3 25/25] openrisc: head: Init r0 to 0 on start Stafford Horne
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