Hi,

I'm trying to run mainline Linux on a smartphone with MSM8916 SoC.
It works surprisingly well, but the coresight devices seem to cause the
following crash shortly after userspace starts:

    Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 0 PID: 32 Comm: kworker/0:1 Not tainted 5.2.0-rc5 #7
    Hardware name: Samsung Galaxy A5 (SM-A500FU) (DT)
    Workqueue: events amba_deferred_retry_func
    pstate: 60000005 (nZCv daif -PAN -UAO)
    pc : amba_device_try_add+0x104/0x2f0
    lr : amba_device_try_add+0xf0/0x2f0
    sp : ffff00001181bd40
    x29: ffff00001181bd40 x28: 0000000000000000 
    x27: ffff80007b258b38 x26: ffff000010f490a0 
    x25: 0000000000000000 x24: ffff000011b35000 
    x23: 0000000000000000 x22: ffff80007b316ed8 
    x21: 0000000000001000 x20: 0000000000000000 
    x19: ffff80007b316c00 x18: 0000000000000000 
    x17: 0000000000000000 x16: 0000000000000000 
    x15: 0000000000000000 x14: ffffffffffffffff 
    x13: 0000000000000000 x12: 0000000000000001 
    x11: 0000000000000000 x10: 0000000000000980 
    x9 : ffff00001181ba00 x8 : ffff80007b126a20 
    x7 : ffff80007a5e0500 x6 : ffff80007b126040 
    x5 : 0000000000000002 x4 : ffff80007db85ba0 
    x3 : 0000000000000000 x2 : ffff000011b35fe0 
    x1 : 0000000000000000 x0 : 0000000000000000 
    Call trace:
     amba_device_try_add+0x104/0x2f0
     amba_deferred_retry_func+0x48/0xc8
     process_one_work+0x1e0/0x320
     worker_thread+0x40/0x428
     kthread+0x120/0x128
     ret_from_fork+0x10/0x18
    Code: 35000ac0 d10082a2 52800001 8b020302 (b9400040) 
    ---[ end trace b664cbefc1cb2294 ]---

In this case I'm using a simple device tree similar to apq8016-sbc,
but it also happens using something as simple as msm8916-mtp.dts
on this particular device.
  (Attached: dmesg log with msm8916-mtp.dts and arm64 defconfig)

I can avoid the crash and boot without any further problems by disabling
every coresight device defined in msm8916.dtsi, e.g.:

	tpiu@820000 { status = "disabled"; };
	funnel@821000 { status = "disabled"; };
	replicator@824000 { status = "disabled"; };
	etf@825000 { status = "disabled"; };
	etr@826000 { status = "disabled"; };
	funnel@841000 { status = "disabled"; };
	debug@850000 { status = "disabled"; };
	debug@852000 { status = "disabled"; };
	debug@854000 { status = "disabled"; };
	debug@856000 { status = "disabled"; };
	etm@85c000 { status = "disabled"; };
	etm@85d000 { status = "disabled"; };
	etm@85e000 { status = "disabled"; };
	etm@85f000 { status = "disabled"; };

I don't have any use for coresight at the moment,
but it seems somewhat odd to put this in the device specific dts.

Any idea what could be causing this crash?
I'm not sure if this is a device-specific issue or possibly some kind of
configuration problem.
  Or is this feature only working on development boards?

Thanks in advance!
Stephan