From nobody Fri Sep 20 11:58:31 2024 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEDC8EEAA5D for ; Thu, 14 Sep 2023 18:43:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242142AbjINSnn (ORCPT ); Thu, 14 Sep 2023 14:43:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242137AbjINSlk (ORCPT ); Thu, 14 Sep 2023 14:41:40 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81A5D2D79; Thu, 14 Sep 2023 11:39:09 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716748; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZmN9t/TOdcgFZ+bmPfvXJ91pUl/2gBg4MuuLLO43TiA=; b=lZZMwROiXF7iHdvpNl7+JZXd8JHRJxlrJO/O2a6l7jlyYnndDS3tbJpaC3zOhAM71f9XrS kcepKr8jfbkARy8zvIO9bEET/k6xLgj2yLmNwyxHjkw2RvlXdoPKqQXnONb/aNnxgpPan+ 9Xz/tRfiwxPA68mPgAGrVkTc+Tl4Fm4VNmw4Nn121e+n9hfCQj9x2IovyO/S2ZS4O7csnI wefbsvV230d8cvWK6HUe27OS7SVPRrn5o38LxRhS//3ha/xyhCazNacRZKLxK7JvVihT5r EPUApL/yX8DGaPnkiSmvn9GiANGQlCO0f0Q0IKmp1Z1vnA+Jz6FDNtHHFKUT1w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716748; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZmN9t/TOdcgFZ+bmPfvXJ91pUl/2gBg4MuuLLO43TiA=; b=W6elDBkcls6Us2UZ8xmu8+vQvXuShUMOnWGdO6CyEEv3LDCbm3pFnjCa1k2m7TDXeaA0rL zJhp0dPySNVny4Dg== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, "David S. Miller" , sparclinux@vger.kernel.org Subject: [PATCH tty v1 67/74] serial: sunsab: Use port lock wrappers Date: Thu, 14 Sep 2023 20:44:24 +0206 Message-Id: <20230914183831.587273-68-john.ogness@linutronix.de> In-Reply-To: <20230914183831.587273-1-john.ogness@linutronix.de> References: <20230914183831.587273-1-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Thomas Gleixner When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner --- drivers/tty/serial/sunsab.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/drivers/tty/serial/sunsab.c b/drivers/tty/serial/sunsab.c index 40eeaf835bba..6aa51a6f8063 100644 --- a/drivers/tty/serial/sunsab.c +++ b/drivers/tty/serial/sunsab.c @@ -310,7 +310,7 @@ static irqreturn_t sunsab_interrupt(int irq, void *dev_= id) unsigned long flags; unsigned char gis; =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 status.stat =3D 0; gis =3D readb(&up->regs->r.gis) >> up->gis_shift; @@ -331,7 +331,7 @@ static irqreturn_t sunsab_interrupt(int irq, void *dev_= id) transmit_chars(up, &status); } =20 - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); =20 if (port) tty_flip_buffer_push(port); @@ -473,12 +473,12 @@ static void sunsab_send_xchar(struct uart_port *port,= char ch) if (ch =3D=3D __DISABLED_CHAR) return; =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 sunsab_tec_wait(up); writeb(ch, &up->regs->w.tic); =20 - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } =20 /* port->lock held by caller. */ @@ -499,7 +499,7 @@ static void sunsab_break_ctl(struct uart_port *port, in= t break_state) unsigned long flags; unsigned char val; =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 val =3D up->cached_dafo; if (break_state) @@ -512,7 +512,7 @@ static void sunsab_break_ctl(struct uart_port *port, in= t break_state) if (test_bit(SAB82532_XPR, &up->irqflags)) sunsab_tx_idle(up); =20 - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } =20 /* port->lock is not held. */ @@ -527,7 +527,7 @@ static int sunsab_startup(struct uart_port *port) if (err) return err; =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 /* * Wait for any commands or immediate characters @@ -582,7 +582,7 @@ static int sunsab_startup(struct uart_port *port) set_bit(SAB82532_ALLS, &up->irqflags); set_bit(SAB82532_XPR, &up->irqflags); =20 - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); =20 return 0; } @@ -594,7 +594,7 @@ static void sunsab_shutdown(struct uart_port *port) container_of(port, struct uart_sunsab_port, port); unsigned long flags; =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 /* Disable Interrupts */ up->interrupt_mask0 =3D 0xff; @@ -628,7 +628,7 @@ static void sunsab_shutdown(struct uart_port *port) writeb(tmp, &up->regs->rw.ccr0); #endif =20 - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); free_irq(up->port.irq, up); } =20 @@ -779,9 +779,9 @@ static void sunsab_set_termios(struct uart_port *port, = struct ktermios *termios, unsigned int baud =3D uart_get_baud_rate(port, termios, old, 0, 4000000); unsigned int quot =3D uart_get_divisor(port, baud); =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); sunsab_convert_to_sab(up, termios->c_cflag, termios->c_iflag, baud, quot); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } =20 static const char *sunsab_type(struct uart_port *port) @@ -857,15 +857,15 @@ static void sunsab_console_write(struct console *con,= const char *s, unsigned n) int locked =3D 1; =20 if (up->port.sysrq || oops_in_progress) - locked =3D spin_trylock_irqsave(&up->port.lock, flags); + locked =3D uart_port_trylock_irqsave(&up->port, &flags); else - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 uart_console_write(&up->port, s, n, sunsab_console_putchar); sunsab_tec_wait(up); =20 if (locked) - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } =20 static int sunsab_console_setup(struct console *con, char *options) @@ -914,7 +914,7 @@ static int sunsab_console_setup(struct console *con, ch= ar *options) */ sunsab_startup(&up->port); =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 /* * Finally, enable interrupts @@ -932,7 +932,7 @@ static int sunsab_console_setup(struct console *con, ch= ar *options) sunsab_convert_to_sab(up, con->cflag, 0, baud, quot); sunsab_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS); =20 - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); =09 return 0; } --=20 2.39.2