// ke_irql.c - software IRQL skeleton
#include <ke_irql.h>
#include <ke_debug.h>
#include <ke_apc.h>

// Single-CPU bring-up state.  When SMP arrives this becomes per-CPU state.
static volatile KIRQL gCurrentIrql = PASSIVE_LEVEL;

__declspec(dllexport) const char* KeIrqlName(KIRQL irql) {
    switch (irql) {
        case PASSIVE_LEVEL:  return "PASSIVE_LEVEL";
        case APC_LEVEL:      return "APC_LEVEL";
        case DISPATCH_LEVEL: return "DISPATCH_LEVEL";
        case HIGH_LEVEL:     return "HIGH_LEVEL";
        default:
            if (irql >= DIRQL_BASE && irql < HIGH_LEVEL)
                return "DIRQL";
            return "INVALID_IRQL";
    }
}

__declspec(dllexport) KIRQL KeGetCurrentIrql(void) {
    return gCurrentIrql;
}

__declspec(dllexport) KIRQL KeRaiseIrql(KIRQL newIrql) {
    KIRQL oldIrql = gCurrentIrql;

    if (newIrql > HIGH_LEVEL) {
        KePanic("KeRaiseIrql: invalid target IRQL %u\n", (unsigned)newIrql);
    }

    if (newIrql < oldIrql) {
        KePanic("KeRaiseIrql: attempted raise from %s(%u) down to %s(%u)\n",
                KeIrqlName(oldIrql), (unsigned)oldIrql,
                KeIrqlName(newIrql), (unsigned)newIrql);
    }

    gCurrentIrql = newIrql;
    return oldIrql;
}

__declspec(dllexport) void KeLowerIrql(KIRQL oldIrql) {
    KIRQL currentIrql = gCurrentIrql;

    if (oldIrql > HIGH_LEVEL) {
        KePanic("KeLowerIrql: invalid target IRQL %u\n", (unsigned)oldIrql);
    }

    if (oldIrql > currentIrql) {
        KePanic("KeLowerIrql: attempted lower from %s(%u) up to %s(%u)\n",
                KeIrqlName(currentIrql), (unsigned)currentIrql,
                KeIrqlName(oldIrql), (unsigned)oldIrql);
    }

    gCurrentIrql = oldIrql;

    if (oldIrql == PASSIVE_LEVEL && currentIrql != PASSIVE_LEVEL)
        KiDeliverKernelApcs();
}

__declspec(dllexport) void KeAssertIrql(KIRQL expected) {
    KIRQL currentIrql = KeGetCurrentIrql();
    if (currentIrql != expected) {
        KePanic("IRQL assertion failed: expected %s(%u), current %s(%u)\n",
                KeIrqlName(expected), (unsigned)expected,
                KeIrqlName(currentIrql), (unsigned)currentIrql);
    }
}

__declspec(dllexport) void KeAssertIrqlAtOrBelow(KIRQL maxIrql) {
    KIRQL currentIrql = KeGetCurrentIrql();
    if (currentIrql > maxIrql) {
        KePanic("IRQL assertion failed: expected <= %s(%u), current %s(%u)\n",
                KeIrqlName(maxIrql), (unsigned)maxIrql,
                KeIrqlName(currentIrql), (unsigned)currentIrql);
    }
}

__declspec(dllexport) int KeCanWait(void) {
    return KeGetCurrentIrql() == PASSIVE_LEVEL;
}