On Fri, Jun 14, 2019 at 08:09:09PM -0500, Jeremy Linton wrote: > ACPI 6.3 adds additional fields to the MADT GICC > structure to describe SPE PPI's. We pick these out > of the cached reference to the madt_gicc structure > similarly to the core PMU code. We then create a platform > device referring to the IRQ and let the user/module loader > decide whether to load the SPE driver. > > Signed-off-by: Jeremy Linton <[email protected]> > --- > arch/arm64/include/asm/acpi.h | 3 ++ > drivers/perf/arm_pmu_acpi.c | 75 +++++++++++++++++++++++++++++++++++ > include/linux/perf/arm_pmu.h | 2 + > 3 files changed, 80 insertions(+) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 7628efbe6c12..d10399b9f998 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -41,6 +41,9 @@ > (!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \ > (unsigned long)(entry) + (entry)->header.length > (end)) > > +#define ACPI_MADT_GICC_SPE (ACPI_OFFSET(struct acpi_madt_generic_interrupt, > \ > + spe_interrupt) + sizeof(u16)) > + > /* Basic configuration for ACPI */ > #ifdef CONFIG_ACPI > pgprot_t __acpi_get_mem_attribute(phys_addr_t addr); > diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c > index 0f197516d708..f5df100bc4f4 100644 > --- a/drivers/perf/arm_pmu_acpi.c > +++ b/drivers/perf/arm_pmu_acpi.c > @@ -74,6 +74,79 @@ static void arm_pmu_acpi_unregister_irq(int cpu) > acpi_unregister_gsi(gsi); > } > > +#if IS_ENABLED(CONFIG_ARM_SPE_PMU) > +static struct resource spe_resources[] = { > + { > + /* irq */ > + .flags = IORESOURCE_IRQ, > + } > +}; > + > +static struct platform_device spe_dev = { > + .name = ARMV8_SPE_PDEV_NAME, > + .id = -1, > + .resource = spe_resources, > + .num_resources = ARRAY_SIZE(spe_resources) > +}; > + > +/* > + * 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_register_device(void) > +{ > + int cpu, hetid, irq, ret; > + bool first = true; > + u16 gsi = 0; > + > + /* > + * 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) { > + struct acpi_madt_generic_interrupt *gicc; > + > + gicc = acpi_cpu_get_madt_gicc(cpu); > + if (gicc->header.length < ACPI_MADT_GICC_SPE) > + return -ENODEV; > + > + if (first) { > + gsi = gicc->spe_interrupt; > + if (!gsi) > + return -ENODEV; > + hetid = find_acpi_cpu_topology_hetero_id(cpu); > + first = false; > + } else if ((gsi != gicc->spe_interrupt) || > + (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {
OK, after checking ACPI specification again and checking with people involved in dynamic ACPI table generation, I think my earlier concerns can be addressed by having a root node in any system(including multi-socket ones) with IDENTICAL flag set in that root node. With that note for archiving reasons so that we can refer people to in future, Reviewed-by: Sudeep Holla <[email protected]> -- Regards, Sudeep
