>> Not sure I understand logic behind this. With the current code, >> resulting cpu_possible_mask depends on CONFIG_SMP_ON_UP: >> - if it is set, cpu_possible_mask contains (0 1), as initialized in >> arm_dt_init_cpu_maps() >> - if it is not set, cpu_possible_mask contains (0), since >> imx_smp_init_cpus() removes 1 from there. > > Right, adding debug to arch/arm/kernel/setup.c, just before the > "if (is_smp())" shows: > > is_smp() 0 possible 3 present 1 online 1 > > which is totally wrong: if is_smp() is false, we should not be setting > up any possible CPUs. See a patch below to fix that. > > However, this doesn't matter much, because the code in setup.c won't > initialise the SMP operations struct ...
But cpu start code is not the only place in the kernel that uses cpu_present_mask. Are you sure that running with invalid cpu_present_mask has no side effects? > Here's the patch to fix the DT code, which should not be setting > present CPUs when is_smp() is false. I see that this fixes the issue as well. But I still don't understand rationale behind all these is_smp() checks. This makes init sequence different with and without CONFIG_SMP_ON_UP. Isn't kernel intended to run ok without CONFIG_SMP_ON_UP? And if yes - then why not run the same init sequence in both cases? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
