netdev - Re: [PATCH net v3 1/2] ptp: ocp: adjust sysfs entries to expose tty information

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: <ea38ce1d-0b6c-4a49-82f1-4c3d823525b4@kernel.org>
Date: Fri, 16 Aug 2024 07:26:03 +0200
From: Jiri Slaby <jirislaby@...nel.org>
To: Vadim Fedorenko <vadfed@...a.com>,
 Vadim Fedorenko <vadim.fedorenko@...ux.dev>, Jakub Kicinski
 <kuba@...nel.org>, Jonathan Lemon <jonathan.lemon@...il.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH net v3 1/2] ptp: ocp: adjust sysfs entries to expose tty
 information

On 15. 08. 24, 14:59, Vadim Fedorenko wrote:
> Starting v6.8 the serial port subsystem changed the hierarchy of devices
> and symlinks are not working anymore. Previous discussion made it clear
> that the idea of symlinks for tty devices was wrong by design.

Care to link it here?

> Implement
> additional attributes to expose the information. Fixes tag points to the
> commit which introduced the change.
...
> --- a/drivers/ptp/ptp_ocp.c
> +++ b/drivers/ptp/ptp_ocp.c
> @@ -316,6 +316,15 @@ struct ptp_ocp_serial_port {
>   #define OCP_SERIAL_LEN			6
>   #define OCP_SMA_NUM			4
>   
> +enum {
> +	PORT_GNSS,
> +	PORT_GNSS2,
> +	PORT_MAC, /* miniature atomic clock */
> +	PORT_NMEA,
> +
> +	PORT_NUM_MAX
> +};
> +

The conversion to the array needs to go to a separate patch, apparently.

> +static ssize_t
> +ptp_ocp_tty_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct dev_ext_attribute *ea = to_ext_attr(attr);
> +	struct ptp_ocp *bp = dev_get_drvdata(dev);
> +	struct ptp_ocp_serial_port *port;
> +
> +	return sysfs_emit(buf, "ttyS%d", bp->port[(uintptr_t)ea->var].line);

uintptr_t is unusual as Greg points out. It is a correct type per C99 to 
cast from/to pointers, but we usually do "unsigned long". (int wouldn't 
work as it has a different size (on 64bit).)

But looking at the code, uintptr_t is used all over. So perhaps use that 
to be consistent?

> @@ -3960,16 +4017,16 @@ ptp_ocp_summary_show(struct seq_file *s, void *data)
>   	bp = dev_get_drvdata(dev);
>   
>   	seq_printf(s, "%7s: /dev/ptp%d\n", "PTP", ptp_clock_index(bp->ptp));
> -	if (bp->gnss_port.line != -1)
> +	if (bp->port[PORT_GNSS].line != -1)
>   		seq_printf(s, "%7s: /dev/ttyS%d\n", "GNSS1",
> -			   bp->gnss_port.line);
> -	if (bp->gnss2_port.line != -1)
> +			   bp->port[PORT_GNSS].line);
> +	if (bp->port[PORT_GNSS2].line != -1)
>   		seq_printf(s, "%7s: /dev/ttyS%d\n", "GNSS2",
> -			   bp->gnss2_port.line);
> -	if (bp->mac_port.line != -1)
> -		seq_printf(s, "%7s: /dev/ttyS%d\n", "MAC", bp->mac_port.line);
> -	if (bp->nmea_port.line != -1)
> -		seq_printf(s, "%7s: /dev/ttyS%d\n", "NMEA", bp->nmea_port.line);
> +			   bp->port[PORT_GNSS2].line);
> +	if (bp->port[PORT_MAC].line != -1)
> +		seq_printf(s, "%7s: /dev/ttyS%d\n", "MAC", bp->port[PORT_MAC].line);
> +	if (bp->port[PORT_NMEA].line != -1)
> +		seq_printf(s, "%7s: /dev/ttyS%d\n", "NMEA", bp->port[PORT_NMEA].line);

Perhaps you can introduce some to_name() function (mapping enum -> const 
char *)? Can this code be then a three-line for loop?

> @@ -4419,20 +4460,21 @@ ptp_ocp_info(struct ptp_ocp *bp)
>   
>   	ptp_ocp_phc_info(bp);
>   
> -	ptp_ocp_serial_info(dev, "GNSS", bp->gnss_port.line,
> -			    bp->gnss_port.baud);
> -	ptp_ocp_serial_info(dev, "GNSS2", bp->gnss2_port.line,
> -			    bp->gnss2_port.baud);
> -	ptp_ocp_serial_info(dev, "MAC", bp->mac_port.line, bp->mac_port.baud);
> -	if (bp->nmea_out && bp->nmea_port.line != -1) {
> -		bp->nmea_port.baud = -1;
> +	ptp_ocp_serial_info(dev, "GNSS", bp->port[PORT_GNSS].line,
> +			    bp->port[PORT_GNSS].baud);
> +	ptp_ocp_serial_info(dev, "GNSS2", bp->port[PORT_GNSS2].line,
> +			    bp->port[PORT_GNSS2].baud);
> +	ptp_ocp_serial_info(dev, "MAC", bp->port[PORT_MAC].line,
> +			    bp->port[PORT_MAC].baud);
> +	if (bp->nmea_out && bp->port[PORT_NMEA].line != -1) {
> +		bp->port[PORT_NMEA].baud = -1;
>   
>   		reg = ioread32(&bp->nmea_out->uart_baud);
>   		if (reg < ARRAY_SIZE(nmea_baud))
> -			bp->nmea_port.baud = nmea_baud[reg];
> +			bp->port[PORT_NMEA].baud = nmea_baud[reg];
>   
> -		ptp_ocp_serial_info(dev, "NMEA", bp->nmea_port.line,
> -				    bp->nmea_port.baud);
> +		ptp_ocp_serial_info(dev, "NMEA", bp->port[PORT_NMEA].line,
> +				    bp->port[PORT_NMEA].baud);

Maybe even here with if (iterator == PORT_NMEA)?

-- 
js
suse labs