uml: disable kmod-8250-serial
The driver tries to access ioports (0x2f9!!) which UML doesn't have.
This causes lots of warnings to appear on boot:
| WARNING: CPU: 0 PID: 1 at lib/logic_iomem.c:188 serial8250_config_port+0x20a/0x1260
| Invalid writeqb of 0xff at address 2f9
| Modules linked in:
| CPU: 0 UID: 0 PID: 1 Comm: swapper Tainted: G W 6.12.25 #0
| Tainted: [W]=WARN
| Stack:
| Call Trace:
| [<60001000>] ? set_reset_devices+0x0/0x16
| [<60452cba>] ? serial8250_config_port+0x20a/0x1260
| [<6071e91f>] ? dump_stack_lvl+0x55/0x71
| [<606e127c>] ? _printk+0x0/0x4f
| [<60044bbb>] ? __warn+0x11b/0x120
| [<6003b5d0>] ? um_set_signals+0x0/0x40
| [<606de721>] ? warn_slowpath_fmt+0x81/0x8c
| [<606de6a0>] ? warn_slowpath_fmt+0x0/0x8c
| [<60452cba>] ? serial8250_config_port+0x20a/0x1260
(they are even recursive!)
Now, the situation gets more confusing. Because from what I can tell,
this was seemingly done intenionally. Upstream patches in related areas:
|commit ddd268c42871b78c75e12a5c28207fb481138f41
|Author: Niklas Schnelle <[email protected]>
|Date: Wed Apr 3 14:43:00 2024 +0200
|
| um: Select HAS_IOREMAP for UML_IOMEM_EMULATION
|
| In a future patch HAS_IOPORT=n will disable inb()/outb() and friends at
| compile time. UML supports these via its UML_IOMEM_EMULATION so let that
| select HAS_IOPORT and also reflect this in NO_IOPORT_MAP.
hint that there's ongoing work in this area. But unfortunately, this future
hasn't arrived yet. Once this future arrives, please nuke this patch.
Signed-off-by: Christian Lamparter <[email protected]>
Christian Lamparter