netdev - Re: [PATCH v5 1/1] net: fec: ptp: avoid register access when ipg clock is disabled

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 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]

Date:	Fri, 22 Aug 2014 10:46:25 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	b38611@...escale.com
Cc:	richardcochran@...il.com, netdev@...r.kernel.org
Subject: Re: [PATCH v5 1/1] net: fec: ptp: avoid register access when ipg
 clock is disabled

From: Fugang Duan <b38611@...escale.com>
Date: Thu, 21 Aug 2014 17:09:38 +0800

> The current kernel hang on i.MX6SX with rootfs mount from MMC.
> The root cause is that ptp uses a periodic timer to access enet register
> even if ipg clock is disabled.
> 
> FEC ptp driver start one period timer to read 1588 counter register in the
> ptp init function that is called after FEC driver is probed.
> 
> To save power, after FEC probe finish, FEC driver disable all clocks including
> ipg clock that is needed for register access.
> 
> i.MX5x, i.MX6q/dl/sl FEC register access don't cause system hang when ipg clock
> is disabled, just return zero value. But for i.MX6sx SOC, it cause system hang.
> 
> To avoid the issue, we need to check ptp clock status before ptp timer count access.
> 
> Signed-off-by: Fugang Duan <B38611@...escale.com>

Applied, thanks.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html