linux-kernel - Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown

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: <55BAC67E.1010400@hurleysoftware.com>
Date:	Thu, 30 Jul 2015 20:51:10 -0400
From:	Peter Hurley <peter@...leysoftware.com>
To:	John Ogness <john.ogness@...utronix.de>
CC:	linux-kernel@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Tony Lindgren <tony@...mide.com>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	linux-omap@...r.kernel.org, nsekhar@...com, nm@...com,
	linux-serial@...r.kernel.org
Subject: Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown

Hi John,

On 07/30/2015 06:54 PM, John Ogness wrote:
> If DMA is active during a shutdown, a delayed restore of the
> registers may be pending. The restore must be performed after
> the DMA is stopped, otherwise the delayed restore remains
> pending and will fire upon the first DMA TX complete of a
> totally different serial session.
> 
> Signed-off-by: John Ogness <john.ogness@...utronix.de>
> ---
>  drivers/tty/serial/8250/8250_omap.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
> index 5b39892..25f6255 100644
> --- a/drivers/tty/serial/8250/8250_omap.c
> +++ b/drivers/tty/serial/8250/8250_omap.c
> @@ -657,9 +657,15 @@ static void omap_8250_shutdown(struct uart_port *port)
>  	up->ier = 0;
>  	serial_out(up, UART_IER, 0);
>  
> -	if (up->dma)
> +	if (up->dma) {
>  		serial8250_release_dma(up);
>  
> +		if (priv->delayed_restore) {
> +			priv->delayed_restore = 0;
> +			omap8250_restore_regs(up);
> +		}

I was never really a fan of the deferred set_termios();
I think it's more appropriate to wait for tx dma to
complete in omap_8250_set_termios().

Regards,
Peter Hurley


> +	}
> +
>  	/*
>  	 * Disable break condition and FIFOs
>  	 */
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/