netdev - Re: [net-next] net: ethernet: rtsn: Add support for Renesas Ethernet-TSN

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <7c8d6791-ea36-45fd-be07-df789263890f@app.fastmail.com>
Date: Thu, 18 Apr 2024 21:03:51 +0200
From: "Arnd Bergmann" <arnd@...db.de>
To: "Simon Horman" <horms@...nel.org>,
 Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
Cc: "Yoshihiro Shimoda" <yoshihiro.shimoda.uh@...esas.com>,
 "David S . Miller" <davem@...emloft.net>,
 "Eric Dumazet" <edumazet@...gle.com>, "Jakub Kicinski" <kuba@...nel.org>,
 "Paolo Abeni" <pabeni@...hat.com>, Netdev <netdev@...r.kernel.org>,
 Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [net-next] net: ethernet: rtsn: Add support for Renesas Ethernet-TSN

On Thu, Apr 18, 2024, at 20:32, Simon Horman wrote:
>
> Hi Niklas,
>
> I think that the use of __iowbm() means that this will not
> compile for many architectures: grep indicates it
> is only defined for arm, arm64, and arc.
>
> Perhaps COMPILE_TEST should be qualified somehow?

>> +	/* Re-enable TX/RX interrupts */
>> +	spin_lock_irqsave(&priv->lock, flags);
>> +	rtsn_ctrl_data_irq(priv, true);
>> +	__iowmb();
>> +	spin_unlock_irqrestore(&priv->lock, flags);

I think this needs a comment anyway: what is this trying
to serialize?

The arm64 __iowmb() usually tries to ensure that a memory
write to a coherent buffer is complete before a following
writel() is sent to the bus, but this one appears to be
after the writel() where it has no effect because the
transaction may still be in flight on the bus after it
has left the store buffer.

      Arnd