• Lorenzo Pieralisi's avatar
    arm64: kernel: implement ACPI parking protocol · 5e89c55e
    Lorenzo Pieralisi authored
    The SBBR and ACPI specifications allow ACPI based systems that do not
    implement PSCI (eg systems with no EL3) to boot through the ACPI parking
    protocol specification[1].
    
    This patch implements the ACPI parking protocol CPU operations, and adds
    code that eases parsing the parking protocol data structures to the
    ARM64 SMP initializion carried out at the same time as cpus enumeration.
    
    To wake-up the CPUs from the parked state, this patch implements a
    wakeup IPI for ARM64 (ie arch_send_wakeup_ipi_mask()) that mirrors the
    ARM one, so that a specific IPI is sent for wake-up purpose in order
    to distinguish it from other IPI sources.
    
    Given the current ACPI MADT parsing API, the patch implements a glue
    layer that helps passing MADT GICC data structure from SMP initialization
    code to the parking protocol implementation somewhat overriding the CPU
    operations interfaces. This to avoid creating a completely trasparent
    DT/ACPI CPU operations layer that would require creating opaque
    structure handling for CPUs data (DT represents CPU through DT nodes, ACPI
    through static MADT table entries), which seems overkill given that ACPI
    on ARM64 mandates only two booting protocols (PSCI and parking protocol),
    so there is no need for further protocol additions.
    
    Based on the original work by Mark Salter <msalter@redhat.com>
    
    [1] https://acpica.org/sites/acpica/files/MP%20Startup%20for%20ARM%20platforms.docxSigned-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Tested-by: default avatarLoc Ho <lho@apm.com>
    Cc: Will Deacon <will.deacon@arm.com>
    Cc: Hanjun Guo <hanjun.guo@linaro.org>
    Cc: Sudeep Holla <sudeep.holla@arm.com>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Mark Salter <msalter@redhat.com>
    Cc: Al Stone <ahs3@redhat.com>
    [catalin.marinas@arm.com: Added WARN_ONCE(!acpi_parking_protocol_valid() on the IPI]
    Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    5e89c55e
smp.c 18.5 KB