diff options
author | Geert Uytterhoeven <geert+renesas@glider.be> | 2015-11-27 11:13:48 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-12 23:05:28 -0800 |
commit | e1dd3bef6d03c908b173259229b96074d57fccc8 (patch) | |
tree | ff5d5c92de7063fadd7358df5563578b324fe966 /drivers/tty | |
parent | d09959e7529451a1c302197fb1396ed5b835f6d3 (diff) | |
download | op-kernel-dev-e1dd3bef6d03c908b173259229b96074d57fccc8.zip op-kernel-dev-e1dd3bef6d03c908b173259229b96074d57fccc8.tar.gz |
serial: earlycon: Add missing spinlock initialization
If an earlycon console driver needs to acquire the uart_port.lock
spinlock for serial console output, and CONFIG_DEBUG_SPINLOCK=y:
BUG: spinlock bad magic on CPU#0, swapper/0
lock: sci_ports+0x0/0x3480, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.0-rc2-koelsch-g62ea5edf143bb1d0-dirty #2083
Hardware name: Generic R8A7791 (Flattened Device Tree)
[<c00173a0>] (unwind_backtrace) from [<c0013094>] (show_stack+0x10/0x14)
[<c0013094>] (show_stack) from [<c01f2338>] (dump_stack+0x70/0x8c)
[<c01f2338>] (dump_stack) from [<c00702d8>] (do_raw_spin_lock+0x20/0x190)
[<c00702d8>] (do_raw_spin_lock) from [<c0267590>] (serial_console_write+0x4c/0x130)
[<c0267590>] (serial_console_write) from [<c00734c4>] (call_console_drivers.constprop.13+0xc8/0xec)
[<c00734c4>] (call_console_drivers.constprop.13) from [<c0074ef0>] (console_unlock+0x354/0x440)
[<c0074ef0>] (console_unlock) from [<c0075bb4>] (register_console+0x2a0/0x394)
[<c0075bb4>] (register_console) from [<c06cb750>] (of_setup_earlycon+0x90/0xa4)
[<c06cb750>] (of_setup_earlycon) from [<c06cfb60>] (setup_of_earlycon+0x118/0x13c)
[<c06cfb60>] (setup_of_earlycon) from [<c06b34ac>] (do_early_param+0x64/0xb4)
[<c06b34ac>] (do_early_param) from [<c00472c0>] (parse_args+0x254/0x350)
[<c00472c0>] (parse_args) from [<c06b3860>] (parse_early_options+0x2c/0x3c)
[<c06b3860>] (parse_early_options) from [<c06b389c>] (parse_early_param+0x2c/0x40)
[<c06b389c>] (parse_early_param) from [<c06b5b08>] (setup_arch+0x520/0xaf0)
[<c06b5b08>] (setup_arch) from [<c06b3948>] (start_kernel+0x94/0x370)
[<c06b3948>] (start_kernel) from [<40008090>] (0x40008090)
Initialize the spinlock in of_setup_earlycon() and register_earlycon(),
to fix this for both DT-based and legacy earlycon. If the driver would
reinitialize the spinlock again, this is harmless, as it's allowed to
reinitialize an unlocked spinlock.
Alternatives are:
- Drivers having an early_serial_console_write() that only performs
the core functionality of serial_console_write(), without acquiring
the lock (which may be unsafe, depending on the hardware),
- Drivers initializing the spinlock in their private earlycon setup
functions.
As uart_port is owned by generic serial_core, and uart_port.lock is
initialized by uart_add_one_port() for the normal case, this can better
be handled in the earlycon core.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Reported-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r-- | drivers/tty/serial/earlycon.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index f096360..b5b2f2b 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -115,6 +115,7 @@ static int __init register_earlycon(char *buf, const struct earlycon_id *match) if (buf && !parse_options(&early_console_dev, buf)) buf = NULL; + spin_lock_init(&port->lock); port->uartclk = BASE_BAUD * 16; if (port->mapbase) port->membase = earlycon_map(port->mapbase, 64); @@ -202,6 +203,7 @@ int __init of_setup_earlycon(unsigned long addr, int err; struct uart_port *port = &early_console_dev.port; + spin_lock_init(&port->lock); port->iotype = UPIO_MEM; port->mapbase = addr; port->uartclk = BASE_BAUD * 16; |