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Groups > linux.kernel > #1519528
| From | Lu Baolu <baolu.lu@linux.intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability |
| Date | 2016-11-11 03:50 +0100 |
| Message-ID | <sCa4F-6Jf-5@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <syzuG-4cJ-5@gated-at.bofh.it> <sBxwm-5sn-31@gated-at.bofh.it> <sBMlI-77l-9@gated-at.bofh.it> <sBTnb-3hK-9@gated-at.bofh.it> <sC9Lj-6Cw-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Hi,
On 11/11/2016 10:24 AM, Lu Baolu wrote:
>> The only thing you can do to make this work is to prevent printing in NMI
>> > context:
>> >
>> > write()
>> > {
>> > if (in_nmi())
>> > return;
>> >
>> > raw_spinlock_irqsave(&lock, flags);
>> > ....
>> >
>> > That fully serializes the writes and just ignores NMI context printks. Not
>> > optimal, but I fear that's all you can do.
> Yes. But I want to add a bit more.
>
> write()
> {
> if (in_nmi() && raw_spin_is_locked(&lock)) {
> trace("... ...");
> return;
> }
>
> raw_spinlock_irqsave(&lock, flags);
> ....
Or...?
write()
{
if (in_nmi() && raw_spin_is_locked(&lock)) {
save_nmi_message_in_local_buf();
set_nmi_message_pending_flag();
return;
}
if (nmi_message_pending_flag_is_set()) {
write_nmi_message();
clear_nmi_message_pending_flag();
}
raw_spinlock_irqsave(&lock, flags);
....
Best regards,
Lu Baolu
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[PATCH v4 0/4] usb: early: add support for early printk through USB3 debug port Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-01 06:10 +0100
[PATCH v4 4/4] usb: doc: add document for USB3 debug port usage Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-01 06:10 +0100
[PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-01 06:10 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Thomas Gleixner <tglx@linutronix.de> - 2016-11-09 10:30 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-10 02:20 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Thomas Gleixner <tglx@linutronix.de> - 2016-11-09 10:40 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-10 02:30 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Thomas Gleixner <tglx@linutronix.de> - 2016-11-10 10:00 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Peter Zijlstra <peterz@infradead.org> - 2016-11-10 12:50 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-11 05:40 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Peter Zijlstra <peterz@infradead.org> - 2016-11-11 13:30 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-12 08:40 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Thomas Gleixner <tglx@linutronix.de> - 2016-11-12 12:40 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-11 03:30 +0100
Re: [PATCH v4 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-11 03:50 +0100
[PATCH v4 2/4] x86: add support for earlyprintk via USB3 debug port Lu Baolu <baolu.lu@linux.intel.com> - 2016-11-01 06:10 +0100
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