Konstantin Demin
c3d09a3e94
imported from https://salsa.debian.org/kernel-team/linux.git commit 9d5cc9d9d6501d7f1dd7e194d4b245bd0b6c6a22 version 6.11.4-1
126 lines
4.1 KiB
Diff
126 lines
4.1 KiB
Diff
From: John Ogness <john.ogness@linutronix.de>
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Date: Tue, 20 Aug 2024 08:35:37 +0206
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Subject: [PATCH 11/54] serial: core: Introduce wrapper to set @uart_port->cons
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.11/older/patches-6.11-rt7.tar.xz
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Introduce uart_port_set_cons() as a wrapper to set @cons of a
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uart_port. The wrapper sets @cons under the port lock in order
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to prevent @cons from disappearing while another context is
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holding the port lock. This is necessary for a follow-up
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commit relating to the port lock wrappers, which rely on @cons
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not changing between lock and unlock.
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Tested-by: Théo Lebrun <theo.lebrun@bootlin.com> # EyeQ5, AMBA-PL011
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Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Reviewed-by: Petr Mladek <pmladek@suse.com>
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Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
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Link: https://lore.kernel.org/r/20240820063001.36405-12-john.ogness@linutronix.de
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Signed-off-by: Petr Mladek <pmladek@suse.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/tty/serial/8250/8250_core.c | 6 +++---
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drivers/tty/serial/amba-pl011.c | 2 +-
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drivers/tty/serial/serial_core.c | 16 ++++++++--------
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include/linux/serial_core.h | 17 +++++++++++++++++
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4 files changed, 29 insertions(+), 12 deletions(-)
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--- a/drivers/tty/serial/8250/8250_core.c
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+++ b/drivers/tty/serial/8250/8250_core.c
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@@ -423,11 +423,11 @@ static int univ8250_console_setup(struct
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port = &serial8250_ports[co->index].port;
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/* link port to console */
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- port->cons = co;
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+ uart_port_set_cons(port, co);
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retval = serial8250_console_setup(port, options, false);
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if (retval != 0)
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- port->cons = NULL;
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+ uart_port_set_cons(port, NULL);
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return retval;
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}
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@@ -485,7 +485,7 @@ static int univ8250_console_match(struct
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continue;
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co->index = i;
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- port->cons = co;
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+ uart_port_set_cons(port, co);
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return serial8250_console_setup(port, options, true);
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}
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--- a/drivers/tty/serial/amba-pl011.c
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+++ b/drivers/tty/serial/amba-pl011.c
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@@ -2480,7 +2480,7 @@ static int pl011_console_match(struct co
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continue;
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co->index = i;
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- port->cons = co;
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+ uart_port_set_cons(port, co);
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return pl011_console_setup(co, options);
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}
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--- a/drivers/tty/serial/serial_core.c
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+++ b/drivers/tty/serial/serial_core.c
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@@ -3176,8 +3176,15 @@ static int serial_core_add_one_port(stru
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state->uart_port = uport;
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uport->state = state;
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+ /*
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+ * If this port is in use as a console then the spinlock is already
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+ * initialised.
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+ */
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+ if (!uart_console_registered(uport))
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+ uart_port_spin_lock_init(uport);
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+
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state->pm_state = UART_PM_STATE_UNDEFINED;
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- uport->cons = drv->cons;
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+ uart_port_set_cons(uport, drv->cons);
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uport->minor = drv->tty_driver->minor_start + uport->line;
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uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
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drv->tty_driver->name_base + uport->line);
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@@ -3186,13 +3193,6 @@ static int serial_core_add_one_port(stru
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goto out;
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}
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- /*
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- * If this port is in use as a console then the spinlock is already
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- * initialised.
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- */
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- if (!uart_console_registered(uport))
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- uart_port_spin_lock_init(uport);
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-
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if (uport->cons && uport->dev)
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of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
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--- a/include/linux/serial_core.h
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+++ b/include/linux/serial_core.h
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@@ -609,6 +609,23 @@ static inline void __uart_port_unlock_ir
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}
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/**
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+ * uart_port_set_cons - Safely set the @cons field for a uart
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+ * @up: The uart port to set
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+ * @con: The new console to set to
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+ *
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+ * This function must be used to set @up->cons. It uses the port lock to
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+ * synchronize with the port lock wrappers in order to ensure that the console
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+ * cannot change or disappear while another context is holding the port lock.
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+ */
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+static inline void uart_port_set_cons(struct uart_port *up, struct console *con)
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+{
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+ unsigned long flags;
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+
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+ __uart_port_lock_irqsave(up, &flags);
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+ up->cons = con;
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+ __uart_port_unlock_irqrestore(up, flags);
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+}
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+/**
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* uart_port_lock - Lock the UART port
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* @up: Pointer to UART port structure
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*/
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