linux-kernel - Re: [PATCH tty-next v1 2/4] serial: 8250: Do not set UART_LSR_THRE in @read_status

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: <Z2CPaOehREibSzVD@smile.fi.intel.com>
Date: Mon, 16 Dec 2024 22:36:56 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: John Ogness <john.ogness@...utronix.de>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>,
	Esben Haabendal <esben@...nix.com>, linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org, Kevin Hilman <khilman@...libre.com>,
	Markus Schneider-Pargmann <msp@...libre.com>,
	Udit Kumar <u-kumar1@...com>,
	Griffin Kroah-Hartman <griffin@...ah.com>,
	Arnd Bergmann <arnd@...db.de>,
	Rengarajan S <rengarajan.s@...rochip.com>,
	Lino Sanfilippo <l.sanfilippo@...bus.com>,
	Niklas Schnelle <schnelle@...ux.ibm.com>,
	Serge Semin <fancer.lancer@...il.com>,
	Peter Collingbourne <pcc@...gle.com>
Subject: Re: [PATCH tty-next v1 2/4] serial: 8250: Do not set UART_LSR_THRE
 in @read_status_mask

On Mon, Dec 16, 2024 at 06:18:42PM +0106, John Ogness wrote:
> Since Linux 2.1.8 @read_status_mask is no longer used as a
> general control of which bits are used from the LSR register.

The curious ones may add history/history.git to their repo and run
`git show 2.1.8 -- drivers/char/serial.c` to see how it was done.

> Instead it has become an additional mask applied to
> @ignore_status_mask. Since UART_LSR_THRE is never set for
> @ignore_status_mask, it serves no purpose to set it for
> @read_status_mask. In fact, it propagates the misconception
> that @read_status_mask can be used as a general mask for LSR
> bits.

-- 
With Best Regards,
Andy Shevchenko