[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 3/6] xen/arm: gic: Use the correct CPU ID
On Wed, 2013-09-25 at 16:42 +0100, Julien Grall wrote: > On 09/25/2013 04:35 PM, Ian Campbell wrote: > > On Fri, 2013-09-20 at 16:03 +0100, Julien Grall wrote: > >> +static unsigned int gic_cpu_mask(const cpumask_t *cpumask) > >> +{ > >> + unsigned int cpu; > >> + unsigned int mask = 0; > >> + cpumask_t possible_mask; > >> + > >> + cpumask_and(&possible_mask, cpumask, &cpu_possible_map); > >> + for_each_cpu(cpu, &possible_mask) > >> + { > >> + ASSERT(cpu < NR_GIC_CPU_IF); > >> + ASSERT(__per_cpu_offset[cpu] != -(long)__per_cpu_start); > > > > This should be INVALID_PERCPU_AREA, but that is private to percpu.c. I > > think we can live without this check. After all the CPU is in possible > > map. > > Being in cpu possible map doesn't mean that the per cpu region is > initialized for the given cpu. So you expect this ASSERT to trigger in practice? That's not good... > I have noticed the INVALID_PERCPU_AREA is the same both Intel and ARM > platform. Can we move this define in percpu.h? I'm wondering if it should be the same, I think it was chosen on x86 to result in a non-canonical address (i.e. a guaranteed fault) and ARM copied it. __per_cpu_start on ARM is in the first 2MB so -__per_cpu_start is 2MB from the top of the 64 bit address space, which is also invalid. I think, Tim, did you consider this or just copy the x86 value? Anyway, my point is that they are the same only through coincidence ;-) Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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