On 11/22/24 14:51, Arnd Bergmann wrote:
On Fri, Nov 22, 2024, at 21:44, Guenter Roeck wrote:
On 11/22/24 11:24, Arnd Bergmann wrote:
serial8250_setup_port() is where it ends up using the
uninitialized serial8250_ports[index] contents. Since
port->iotype is not set to anything here, it defaults to
'0', which happens to be UPIO_PORT.
The reason it doesn't immediately crash and burn is that
this is still only setting up the structures for later
use, but I assume that trying to use console=ttyS0, or
opening /dev/ttyS0 on the uninitialized port would
then cause an oops.
All four affected platforms use ttyS0, only it is mmio based,
not io port based.
Right, so I think the problem is really the 8250_platform.c
file trying to handle all possible cases on x86 (acpi,
isapnp, legacy isa) that may define the same UARTs, but
also trying to handle non-legacy ports with their own
special cases on other architectures.
The patch below is a first idea of how we can skip the
legacy ISA case on architectures that don't define those.
If this works, we can try to come up with a better way of
doing that. Ideally all the pre-DT boardfile machines that
define their own "serial8250" platform_device (with platform_data)
should use a different identifier the x86-legacy case that
uses the platform_device (without platform_data). Similarly,
I think the riscv special ACPI port needs its own trivial
driver without all the ISA magic.
Arnd
diff --git a/drivers/tty/serial/8250/8250_platform.c b/drivers/tty/serial/8250/8250_platform.c
index 66fd6d5d4835..610b31517734 100644
--- a/drivers/tty/serial/8250/8250_platform.c
+++ b/drivers/tty/serial/8250/8250_platform.c
That didn't work.
[ 0.005735] Console: colour dummy device 80x25
[ 0.006393] BUG: spinlock bad magic on CPU#0, swapper/0
[ 0.006459] lock: serial8250_ports+0x0/0x980, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[ 0.007102] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.12.0-07881-g6206e39999ae #1
[ 0.007359] Stack:
[ 0.007671] > 00000100 00000000 d09f9e10 d0951c2c
[ 0.007765] d0951c2c 00000000 00000000 d0b06170
[ 0.007841] 9003f5ee d09f9e60 00000055 d0dd9900
[ 0.007884] 00000000 00000004 d09f9e40 00000000
[ 0.007925] 9003f681 d09f9e80 d0dd9900 d08f5924
[ 0.007976] > 00000000 d08f5890 ffffffff 00000000
[ 0.008019] 906f66b9 d09f9ea0 d0dd9900 00000000
[ 0.008059] > 00000000 00000480 00000000 d0a06d74
[ 0.008099] 904efe6a d09f9ec0 d0dd9900 00060300
[ 0.008139] > 00000000 00000000 00000001 00000000
[ 0.008180] 9004368d d09f9ef0 d0aa7238 d7ff70a4
[ 0.008220] > d04efe6a 00000000 00000001 00000000
[ 0.008260] 00000000 00000000 00000001 00000000
[ 0.008301] 90044a84 d09f9f10 d0aa7238 d04efe14
[ 0.008340] > d0dd9900 000000c4 d0a06d74 d0a00400
[ 0.008381] 90ae6710 d09f9f30 d0aa7238 d0cedea0
[ 0.008443] Call Trace:
[ 0.008502] [<d06ed63d>] dump_stack+0x9/0xc
[ 0.008624] [<d003f5ee>] spin_dump+0x4a/0x78
[ 0.008677] [<d003f681>] do_raw_spin_lock+0x1d/0x68
[ 0.008727] [<d06f66b9>] _raw_spin_lock_irqsave+0x41/0x54
[ 0.008780] [<d04efe6a>] univ8250_console_setup+0x56/0x104
[ 0.008829] [<d004368d>] try_enable_preferred_console+0x75/0xf4
[ 0.008877] [<d0044a84>] register_console+0xf4/0x3e4
[ 0.008923] [<d0ae6710>] univ8250_console_init+0x20/0x24
[ 0.008970] [<d0ad44f0>] console_init+0x18/0x20
[ 0.009018] [<d0acfdaf>] start_kernel+0x3db/0x4cc
[ 0.009063] [<d06ee02b>] _startup+0x13b/0x13b
That was xtensa. Others are just silent.
Guenter
