ext.cxxm

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/// SPDX-License-Identifier: Apache-2.0
/// @file arch/s390x/trap/ext.cxxm
/// @brief Centralized external-interruption dispatcher.
 
export module arch.s390x.trap.ext;
import arch.s390x.cpu.lowcore;
import arch.s390x.cpu.irq;
import arch.s390x.cpu.cputimer;
import arch.s390x.cpu.clock;
import arch.s390x.cpu.cpumask;
import arch.s390x.cpu.psw;
import zxfoundation.sys.irq.consts;
import zxfoundation.sys.irq.core;
import zxfoundation.sched.core;
import zxfoundation.sched.topology.core;
import zxfoundation.dgp.domain.types;
import zxfoundation.base.types;
import zxfoundation.sys.syschk.core;
import zxfoundation.sys.timer.core;
import zxfoundation.sys.printk.core;
import zxfoundation.sys.timer.types;
import zxfoundation.smp.csd.core;
import lib.error;
import lib.softirq.core;
 
export {
 
namespace arch::s390x::trap::ext {
 
    /// @brief Raw z/Architecture external-interruption codes per PoP §7-3.
    /// @{
    constexpr u16 EXT_INTERRUPT_KEY      = 0x0040;  ///< External-interrupt-key.
    constexpr u16 EXT_CLOCK_COMPARATOR   = 0x1004;  ///< Clock comparator.
    constexpr u16 EXT_CPU_TIMER          = 0x1005;  ///< CPU timer.
    constexpr u16 EXT_WARNING_TRACK      = 0x1007;  ///< Warning track (STP).
    constexpr u16 EXT_MALFUNCTION_ALERT  = 0x1200;  ///< Malfunction alert.
    constexpr u16 EXT_EMERGENCY_SIGNAL   = 0x1201;  ///< Emergency-signal IPI.
    constexpr u16 EXT_EXTERNAL_CALL      = 0x1202;  ///< External-call IPI.
    constexpr u16 EXT_TIMING_ALERT       = 0x1406;  ///< STP timing alert.
    constexpr u16 EXT_MEASUREMENT_ALERT  = 0x1407;  ///< CPU-MF measurement alert.
    constexpr u16 EXT_SERVICE_SIGNAL     = 0x2401;  ///< SCLP service signal.
    constexpr u16 EXT_CP_SERVICE         = 0x2603;  ///< CP service (pfault).
    /// @}
 
    namespace detail {
 
        /// @brief Acknowledge the current external interrupt in lowcore.
        auto ack_lowcore() noexcept -> void {
            auto* lc = arch::s390x::cpu::lowcore::get_current();
            lc->ext_int_code = 0U;
        }
 
    } // namespace detail
 
    /// @brief Centralized external-interruption dispatcher.
    /// @param[in,out] frame  Saved interrupt frame from entry.S.
    auto handle(cpu::irq::irq_frame* frame) noexcept -> void {
        auto* lc = cpu::lowcore::get_current();
        const u16 ext_code = lc->ext_int_code;
 
        detail::ack_lowcore();
 
        const u16 irq_nr = zxfoundation::sys::irq::ext_code_to_irq(ext_code);
        if (irq_nr == zxfoundation::sys::irq::IRQ_NR_MAX) {
            zxfoundation::sys::printk::pverbose(
                "ext: unrecognised ext_code {:#06x} — no IRQ slot\n",
                ext_code);
            return;
        }
 
        zxfoundation::sys::irq::irq_dispatch(
            irq_nr, frame, cpu::irq::ZX_IRQ_CLASS_EXT);
 
        namespace irq = zxfoundation::sys::irq;
        if (irq::deferred_test_clear(irq::DEFERRED_RESCHED_BIT)) {
            zxfoundation::sched::sched_resched_current();
        }
 
        if (irq::deferred_test_clear(irq::DEFERRED_MCCK_PENDING_BIT)) {
            // TODO:
            // The actual deferred-MCCK handler is currently inline in the
            // MCCK dispatcher (Phase 3.2 / 11.7 pending); until that chapter
            // is wired we simply acknowledge the bit was set so the trap
            // path stays self-consistent.
            zxfoundation::sys::printk::pverbose(
                "ext: deferred MCCK work armed on cpu={}\n",
                arch::s390x::cpu::lowcore::this_cpu_percpu().cpu_id);
        }
 
        if (irq::deferred_test_clear(irq::DEFERRED_CALL_FUNCTION_BIT)) {
            zxfoundation::smp::csd::drain_cpu();
        }
 
        if (irq::deferred_test_clear(irq::DEFERRED_IRQ_WORK_BIT)) {
            lib::do_softirq();
        }
 
        if (irq::deferred_test_clear(irq::DEFERRED_STOP_CPU_BIT)) {
            const auto cpu_id =
                arch::s390x::cpu::lowcore::this_cpu_percpu().cpu_id;
            zxfoundation::sys::printk::pnotice(
                "ext: stop-cpu deferred work on cpu={} — halting\n", cpu_id);
            arch::s390x::cpu::cpumask::cpu_clear_online(cpu_id);
            zxfoundation::sched::topology::topology_offline_cpu(cpu_id);
            arch::s390x::cpu::psw::disabled_wait();
        }
    }
 
} // namespace arch::s390x::trap::ext
 
} // end export