Messages in this thread | | | Date | Tue, 15 Apr 2014 18:20:00 +0800 | From | Ding Tianhong <> | Subject | Re: [PATCH] arm64: Flush the process's mm context TLB entries when switching |
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On 2014/4/15 16:02, Will Deacon wrote: > On Tue, Apr 15, 2014 at 03:00:24AM +0100, Ding Tianhong wrote: >> On 2014/4/14 21:01, Will Deacon wrote: >>> Hi Ding, >>> >>> On Mon, Apr 14, 2014 at 01:03:12PM +0100, Ding Tianhong wrote: >>>> I met a problem when migrating process by following steps: >>>> >>>> 1) The process was already running on core 0. >>>> 2) Set the CPU affinity of the process to 0x02 and move it to core 1, >>>> it could work well. >>>> 3) Set the CPU affinity of the process to 0x01 and move it to core 0 again, >>>> the problem occurs and the process was killed. >>> >>> [...] >>> >>>> It was a very strange problem that the PC and LR are both 0, and the esr is >>>> 0x83000006, it means that the used for instruction access generated MMU faults >>>> and synchronous external aborts, including synchronous parity errors. >>>> >>>> I try to fix the problem by invalidating the process's TLB entries when switching, >>>> it will make the context stale and pick new one, and then it could work well. >>>> >>>> So I think in some situation that after the process switching, the modification of >>>> the TLB entries in the new core didn't inform all other cores to invalidate the old >>>> TLB entries which was in the inner shareable caches, and then if the process schedule >>>> to another core, the old TLB entries may occur MMU faults. >>> >>> Yes, it sounds like you don't have your TLBs configured correctly. Can you >>> confirm that your EL3 firmware is configuring TLB broadcasting correctly >>> please? >>> >> >> Hi will: >> >> Do you mean the SCR_EL3.NS? > > No, there's usually a CPU-specific register (called something like actlr or > ectlr) which contains bit(s) to enable TLB broadcasting in hardware. Which > CPU are you using? > > Will > Yes,I set the CPUECTLR.SMP to 1 and enable the core to receive TLB broadcast, then fix the problem, thanks for your help, And I use arm64-A57.
Regards Ding > . >
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