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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Feb 14, 2019 at 12:03:57PM -0600, Jeremy Linton wrote: > On 2/14/19 11:11 AM, Will Deacon wrote: > > On Fri, Feb 08, 2019 at 06:47:17PM -0600, Jeremy Linton wrote: > > > +/* > > > + * For lack of a better place, hook the normal PMU MADT walk > > > + * and create a SPE device if we detect a recent MADT with > > > + * a homogeneous PPI mapping. > > > + */ > > > +static int arm_spe_acpi_parse_irqs(void) > > > +{ > > > + int cpu, ret, irq; > > > + u16 gsi = 0; > > > + bool first = true; > > > + > > > + struct acpi_madt_generic_interrupt *gicc; > > > + > > > + /* > > > + * sanity check all the GICC tables for the same interrupt number > > > + * for now we only support homogeneous ACPI/SPE machines. > > > + */ > > > + for_each_possible_cpu(cpu) { > > > + gicc = acpi_cpu_get_madt_gicc(cpu); > > > + > > > + if (gicc->header.length < ACPI_MADT_GICC_SPE) > > > + return -ENODEV; > > > + > > > + if (first) { > > > + gsi = gicc->spe_overflow_interrupt; > > > + if (!gsi) > > > + return -ENODEV; > > > + first = false; > > > + } else if (gsi != gicc->spe_overflow_interrupt) { > > > + pr_warn("ACPI: SPE must have homogeneous interrupts\n"); > > > + return -EINVAL; > > > + } > > > > Unfortunately, I don't think this is sufficient to detect a homogeneous > > system: we'll have to check the MIDRs instead, which is nasty. I would > > personally be in favour of enforcing homogeneity for ACPI systems when we > > bring up secondary CPUs, but I suspect others would disagree. > > Given that all the SPE capable machines i'm aware of at the moment are > homogeneous, are we ok with just doing an online CPU MIDR check for now, and > cleaning that up if/when someone builds a machine and complains? Yeah, I think we added a new bit to the PPTT to tell you that the machine is homogenous, so just check that first and bail if it's not set. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel