diff options
Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0042-tty-serial-pl011-Make-the-locking-work-on-RT.patch | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/debian/patches-rt/0042-tty-serial-pl011-Make-the-locking-work-on-RT.patch b/debian/patches-rt/0042-tty-serial-pl011-Make-the-locking-work-on-RT.patch new file mode 100644 index 000000000..c80dc32de --- /dev/null +++ b/debian/patches-rt/0042-tty-serial-pl011-Make-the-locking-work-on-RT.patch @@ -0,0 +1,60 @@ +From 1db3dc8a6af68447b52efbbf8dbb4d210d23d57b Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Tue, 8 Jan 2013 21:36:51 +0100 +Subject: [PATCH 42/62] tty/serial/pl011: Make the locking work on RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.1/older/patches-6.1.69-rt21.tar.xz + +The lock is a sleeping lock and local_irq_save() is not the optimsation +we are looking for. Redo it to make it work on -RT and non-RT. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +--- + drivers/tty/serial/amba-pl011.c | 17 +++++++++++------ + 1 file changed, 11 insertions(+), 6 deletions(-) + +diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c +index c74eaf2552c3..38eb30b8491b 100644 +--- a/drivers/tty/serial/amba-pl011.c ++++ b/drivers/tty/serial/amba-pl011.c +@@ -2316,18 +2316,24 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) + { + struct uart_amba_port *uap = amba_ports[co->index]; + unsigned int old_cr = 0, new_cr; +- unsigned long flags; ++ unsigned long flags = 0; + int locked = 1; + + clk_enable(uap->clk); + +- local_irq_save(flags); ++ /* ++ * local_irq_save(flags); ++ * ++ * This local_irq_save() is nonsense. If we come in via sysrq ++ * handling then interrupts are already disabled. Aside of ++ * that the port.sysrq check is racy on SMP regardless. ++ */ + if (uap->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&uap->port.lock); ++ locked = spin_trylock_irqsave(&uap->port.lock, flags); + else +- spin_lock(&uap->port.lock); ++ spin_lock_irqsave(&uap->port.lock, flags); + + /* + * First save the CR then disable the interrupts +@@ -2353,8 +2359,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) + pl011_write(old_cr, uap, REG_CR); + + if (locked) +- spin_unlock(&uap->port.lock); +- local_irq_restore(flags); ++ spin_unlock_irqrestore(&uap->port.lock, flags); + + clk_disable(uap->clk); + } +-- +2.43.0 + |