Messages in this thread | | | Subject | Re: 4.5-rc4 kernel is failed to bootup on CN6880 | From | Yang Shi <> | Date | Mon, 22 Feb 2016 11:15:47 -0800 |
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On 2/22/2016 4:43 AM, Aaro Koskinen wrote: > Hi, > > On Fri, Feb 19, 2016 at 05:12:41PM -0800, Yang Shi wrote: >> I tried to boot 4.5-rc4 kernel on my CN6880 board, but it is failed at >> booting up secondary cores. The error is: > With v4.5-rc5, EBB6800 is booting fine: > > [ 0.000000] CPU0 revision is: 000d9108 (Cavium Octeon II) > [...] > [ 2286.273935] SMP: Booting CPU01 (CoreId 1)... > [ 2286.278201] CPU1 revision is: 000d9108 (Cavium Octeon II) > [...] > [ 2287.214953] SMP: Booting CPU31 (CoreId 31)... > [ 2287.224668] CPU31 revision is: 000d9108 (Cavium Octeon II) > [ 2287.224865] Brought up 32 CPUs > >> CPU31 revision is: 000d9101 (Cavium Octeon II) >> SMP: Booting CPU32 (CoreId 32)... >> Secondary boot timeout >> >> I passed "numcores=32" in kernel commandline since there are 32 cores ion >> CN6880. > You shouldn't have CPU32 in that case, the numbering starts from zero. > Also the coremask is 32-bit. > > I can reproduce your issue with CONFIG_NR_CPUS=64. Possibly this code > is incorrect for NR_CPUS bigger than 32: > > /* The present CPUs get the lowest CPU numbers. */ > cpus = 1; > for (id = 0; id < NR_CPUS; id++) { > if ((id != coreid) && (core_mask & (1 << id))) { > set_cpu_possible(cpus, true); > set_cpu_present(cpus, true); > > What CONFIG_NR_CPUS did you use?
Thanks. I did have 48 NR_CPUS set. It works when I changed it to 32.
I think the problem is core_mask is 32 bit. But when NR_CPUS > 32, in "core_mask & (1 << id)" core_mask will be sign extended, then the statement will return non-zero all the time.
Yang
> > A. >
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