Messages in this thread | | | Date | Mon, 22 Feb 2016 12:56:20 -0800 | From | David Daney <> | Subject | Re: 4.5-rc4 kernel is failed to bootup on CN6880 |
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On 02/22/2016 11:15 AM, Yang Shi wrote: > 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. >
That is correct, and perhaps not coincidentally, the reason I have already submitted patches to fix this.
David.
> Yang > >> >> A. >> > >
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