Commits
John Garry committed 10e62b47973
bus: hisi_lpc: Add .remove method to avoid driver unbind crash
The original driver author seemed to be under the impression that a driver
cannot be removed if it does not have a .remove method. Or maybe if it is
a built-in platform driver.
This is not true. This crash can be created:
root@ubuntu:/sys/bus/platform/drivers/hisi-lpc# echo HISI0191\:00 > unbind
root@ubuntu:/sys/bus/platform/drivers/hisi-lpc# ipmitool raw 6 1
Unable to handle kernel paging request at virtual address ffff000010035010
Mem abort info:
ESR = 0x96000047
Exception class = DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000047
CM = 0, WnR = 1
swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000000118b000
[ffff000010035010] pgd=0000041ffbfff003, pud=0000041ffbffe003, pmd=0000041ffbffd003, pte=0000000000000000
Internal error: Oops: 96000047 [#1] PREEMPT SMP
Modules linked in:
CPU: 17 PID: 1473 Comm: ipmitool Not tainted 5.2.0-rc5-00003-gf68c53b414a3-dirty #198
Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT21 Nemo 2.0 RC0 04/18/2018
pstate: 20000085 (nzCv daIf -PAN -UAO)
pc : hisi_lpc_target_in+0x7c/0x120
lr : hisi_lpc_target_in+0x70/0x120
sp : ffff00001efe3930
x29: ffff00001efe3930 x28: ffff841f9f599200
x27: 0000000000000002 x26: 0000000000000000
x25: 0000000000000080 x24: 00000000000000e4
x23: 0000000000000000 x22: 0000000000000064
x21: ffff801fb667d280 x20: 0000000000000001
x19: ffff00001efe39ac x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000
x15: 0000000000000000 x14: 0000000000000000
x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000
x9 : 0000000000000000 x8 : ffff841febe60340
x7 : ffff801fb55c52e8 x6 : 0000000000000000
x5 : 0000000000ffc0e3 x4 : 0000000000000001
x3 : ffff801fb667d280 x2 : 0000000000000001
x1 : ffff000010035010 x0 : ffff000010035000
Call trace:
hisi_lpc_target_in+0x7c/0x120
hisi_lpc_comm_in+0x88/0x98
logic_inb+0x5c/0xb8
port_inb+0x18/0x20
bt_event+0x38/0x808
smi_event_handler+0x4c/0x5a0
check_start_timer_thread.part.4+0x40/0x58
sender+0x78/0x88
smi_send.isra.6+0x94/0x108
i_ipmi_request+0x2c4/0x8f8
ipmi_request_settime+0x124/0x160
handle_send_req+0x19c/0x208
ipmi_ioctl+0x2c0/0x990
do_vfs_ioctl+0xb8/0x8f8
ksys_ioctl+0x80/0xb8
__arm64_sys_ioctl+0x1c/0x28
el0_svc_common.constprop.0+0x64/0x160
el0_svc_handler+0x28/0x78
el0_svc+0x8/0xc
Code: 941d1511 aa0003f9 f94006a0 91004001 (b9000034)
---[ end trace aa842b86af7069e4 ]---
The problem here is that the host goes away but the associated logical PIO
region remains registered, as do the children devices.
Fix by adding a .remove method to tidy-up by removing the child devices
and unregistering the logical PIO region.
Cc: stable@vger.kernel.org
Fixes: adf38bb0b595 ("HISI LPC: Support the LPC host on Hip06/Hip07 with DT bindings")
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>