Re: [Linaro-acpi] [PATCH v3 13/17] ARM64 / ACPI: Add GICv2 specific ACPI boot support

On Monday 01 September 2014 22:57:51 Hanjun Guo wrote:

•   /* Collect CPU base addresses */
  

•   count = acpi_parse_entries(sizeof(struct acpi_table_madt),
  

•                              gic_acpi_parse_madt_cpu, table,
  

•                              ACPI_MADT_TYPE_GENERIC_INTERRUPT,
  

•                              ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES);
  

•   if (count < 0) {
  

•           pr_err("Error during GICC entries parsing\n");
  

•           return -EFAULT;
  

•   } else if (!count) {
  

•           /* No GICC entries provided, use address from MADT header */
  

•           struct acpi_table_madt *madt = (struct acpi_table_madt *)table;
  

•           if (!madt->address)
  

•                   return -EFAULT;
  

•           cpu_phy_base = (u64)madt->address;
  

•   }
  

After I read through ACPI-5.1 section 5.2.12.14, I wonder if this is the best way to treat a missing ACPI_MADT_TYPE_GENERIC_INTERRUPT table.

Do we expect to see those in practice? It seems like using the x86 local APIC address as a fallback for the GIC address is not something we should do unless we absolutely have to support a system that doesn't have the GIC table.

Arnd