From: Thomas Monjalon <thomas@monjalon.net>
To: Phil Yang <Phil.Yang@arm.com>,
Diogo Behrens <diogo.behrens@huawei.com>,
Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
Cc: dev@dpdk.org, nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH] librte_eal: fix mcslock hang on weak memory
Date: Tue, 06 Oct 2020 23:49:45 +0200 [thread overview]
Message-ID: <1947647.zX4bR4m4Ni@thomas> (raw)
In-Reply-To: <DBAPR08MB58148C46395B8592D9AC2B8F98510@DBAPR08MB5814.eurprd08.prod.outlook.com>
31/08/2020 20:45, Honnappa Nagarahalli:
>
> Hi Diogo,
>
> Thanks for your explanation.
>
> As documented in https://developer.arm.com/documentation/ddi0487/fc B2.9.5 Load-Exclusive and Store-Exclusive instruction usage restrictions:
> " Between the Load-Exclusive and the Store-Exclusive, there are no explicit memory accesses, preloads,
> direct or indirect System register writes, address translation instructions, cache or TLB maintenance
> instructions, exception generating instructions, exception returns, or indirect branches."
> [Honnappa] This is a requirement on the software, not on the micro-architecture.
> We are having few discussions internally, will get back soon.
>
> So it is not allowed to insert (1) & (4) between (2, 3). The cmpxchg operation is atomic.
Please what is the conclusion?
next prev parent reply other threads:[~2020-10-06 21:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-26 9:20 Diogo Behrens
2020-08-26 10:17 ` Phil Yang
2020-08-27 8:56 ` Diogo Behrens
2020-08-28 9:19 ` Phil Yang
2020-08-31 18:45 ` Honnappa Nagarahalli
2020-10-06 21:49 ` Thomas Monjalon [this message]
2020-10-07 9:55 ` Diogo Behrens
2020-10-20 11:56 ` Thomas Monjalon
2020-10-20 21:49 ` Honnappa Nagarahalli
2020-11-22 18:07 ` Thomas Monjalon
2020-11-23 15:06 ` Honnappa Nagarahalli
2020-11-23 15:44 ` Stephen Hemminger
2020-11-23 18:16 ` Honnappa Nagarahalli
2020-11-23 18:29 ` Honnappa Nagarahalli
2020-11-23 19:36 ` Stephen Hemminger
2020-11-25 4:50 ` Honnappa Nagarahalli
2020-11-25 8:41 ` Diogo Behrens
2020-11-25 14:16 ` Thomas Monjalon
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