Re: Access to DMA memory while DMA in progress?

2017-10-27 Thread Eduardo Horvath
On Fri, 27 Oct 2017, Mouse wrote: > >> But I'm not sure what sort of sync calls I need to make. [...] > > You want to do a bus_dmamap_sync(BUS_DMASYNC_POSTREAD) [...] > > In the NIC example above, you map the ring buffer with > > BUS_DMA_COHERENT, fill it up and do a > >

Re: Access to DMA memory while DMA in progress?

2017-10-27 Thread Mouse
>>> [...access to DMA buffer while DMA in progress...ordering...] >> Hm! On such hardware, then, you can't count on any particular >> portion of a DMA transfer being visible until the whole transfer is >> finished? > Yes. I'm assuming here that the driver would do a data cache > invalidate (for

Re: Access to DMA memory while DMA in progress?

2017-10-27 Thread Paul.Koning
> On Oct 27, 2017, at 10:36 AM, Mouse wrote: > >>> I would like to read the DMA buffer while DMA is still going on. >>> [...] I'm fine if the CPU's view lags the hardware's view slightly, >>> but I do care about the CPU's view of the DMA write order matching >>> the

Re: Access to DMA memory while DMA in progress?

2017-10-27 Thread Mouse
>> I would like to read the DMA buffer while DMA is still going on. >> [...] I'm fine if the CPU's view lags the hardware's view slightly, >> but I do care about the CPU's view of the DMA write order matching >> the hardware's: that is, if the CPU sees the value written by a >> given DMA cycle,

Re: Access to DMA memory while DMA in progress?

2017-10-27 Thread Paul.Koning
> On Oct 27, 2017, at 9:38 AM, Mouse wrote: > > ... > I would like to read the DMA buffer while DMA is still going on. That > is, I have a buffer of (say) 64K and the hardware is busily writing > into it; I want to read the buffer and see what the hardware has >

Re: MCLGETI in if_msk.c

2017-10-27 Thread Rocky Hotas
Hi Christos! > Sent: Friday, October 27, 2017 at 1:58 PM > From: "Christos Zoulas" > To: tech-kern@netbsd.org > Subject: Re: MCLGETI in if_msk.c > [...] > > OpenBSD: > m = MCLGETI(NULL, M_DONTWAIT, NULL, MCLBYTES); > if (m == NULL) >

Access to DMA memory while DMA in progress?

2017-10-27 Thread Mouse
Back 8 days ago, I asked about bus_dmamap_unload() at splhigh(). Thanks to very helpful off-list responses (thank you - you know who you are!), I think I understand that a little better now. (Summary: no, that can't be counted on to work, and it's documented, just not where I was looking - it's

Re: [Call for Testing] Syzkaller (kernel fuzzing)

2017-10-27 Thread Dmitry Vyukov
On Fri, Oct 27, 2017, 14:50 Kamil Rytarowski wrote: > Please don't burden upstream for every single issue (for now assume > literal meaning: "for any issue"). This worked for a while, as Dmitry > had spare time for syzkaller for !Linux, but this time is over. > I asked Utkarsh to

Re: [Call for Testing] Syzkaller (kernel fuzzing)

2017-10-27 Thread Kamil Rytarowski
Please don't burden upstream for every single issue (for now assume literal meaning: "for any issue"). This worked for a while, as Dmitry had spare time for syzkaller for !Linux, but this time is over. You have asked others for tests, so take the responsibility now to answer feedback reports. I'm

Re: [Call for Testing] Syzkaller (kernel fuzzing)

2017-10-27 Thread Utkarsh Anand
Adding Dmitry Vyukov to CC. He might be able to address your queries better. Regards, Utkarsh Anand On 27/10/2017, Chavdar Ivanov wrote: > I ran them twice; on both occasions somewhere around the fifth hour of work > the laptop became unresponsive; it didn't crash, I could

Re: [Call for Testing] Syzkaller (kernel fuzzing)

2017-10-27 Thread Chavdar Ivanov
I ran them twice; on both occasions somewhere around the fifth hour of work the laptop became unresponsive; it didn't crash, I could switch the wscons, but nothing else, so I had to reset it. The laptop didn't seem particularly hot at the time. It is an old T61p with 4GB memory, running 8.99.5 at