initial commit

src/kern/ipl.zig

@@ -0,0 +1,96 @@
+const std = @import("std");
+const b = @import("base");
+const ke = b.ke;
+const ki = ke.private;
+
+/// Interrupt priority level (IPL)
+pub const Ipl = enum(u8) {
+    /// All interrupts enabled.
+    Zero = 0,
+    /// Preemption disabled.
+    Dispatch = 1,
+    /// Device interrupts disabled.
+    Device = 13,
+    /// All interrupts disabled.
+    High = 15,
+
+    pub fn get_max_software() Ipl {
+        return .Dispatch;
+    }
+};
+
+/// Raise IPL to `new`.
+/// Panics if the current IPL is higher than requested.
+pub fn raise(new: Ipl) Ipl {
+    var cpu = ke.curcpu();
+    const old = cpu.ipl;
+
+    if (@intFromEnum(new) < @intFromEnum(old)) {
+        ke.panic("ke.ipl.raise(): Target IPL ({}) is lower than current IPL ({})\n", .{ new, old });
+    }
+
+    if (@intFromEnum(new) > @intFromEnum(Ipl.get_max_software())) {
+        ki.impl.set_hardware_ipl(new);
+    }
+
+    cpu.ipl = new;
+
+    return old;
+}
+
+/// Lower IPL to `new`.
+/// Panics if the current IPL is lower than requested.
+pub fn lower(new: Ipl) void {
+    var cpu = ke.curcpu();
+    const old = cpu.ipl;
+
+    if (@intFromEnum(new) > @intFromEnum(old)) {
+        ke.panic("ke.ipl.lower(): Target IPL ({}) is higher than current IPL ({})\n", .{ new, old });
+    }
+
+    if (@intFromEnum(new) <= @intFromEnum(Ipl.get_max_software()) and @intFromEnum(old) > @intFromEnum(Ipl.get_max_software())) {
+        ki.impl.set_hardware_ipl(.Zero);
+    }
+
+    if (@intFromEnum(new) < @intFromEnum(Ipl.Dispatch) and is_softint_pending(cpu, .Dispatch)) {
+        ki.dpc.dispatch(cpu);
+    }
+
+    cpu.ipl = new;
+}
+
+comptime {
+    if (!@hasDecl(ki.impl, "set_hardware_ipl")) @compileError("impl must provide set_hardware_ipl()");
+}
+
+/// Set the hardware IPL to `new`
+pub fn set_hardware(new: Ipl) Ipl {
+    var cpu = ke.curcpu();
+    const old = cpu.ipl;
+
+    cpu.ipl = new;
+
+    ki.impl.set_hardware_ipl(new);
+
+    return old;
+}
+
+/// Mark a software interrupt of IPL `ipl` on `cpu` as pending
+pub fn set_softint_pending(cpu: *ke.Cpu, ipl: Ipl) void {
+    std.debug.assert(@intFromEnum(ipl) <= @intFromEnum(Ipl.Dispatch));
+    _ = cpu.pending_softints.bitSet(@intCast(@intFromEnum(ipl)), .monotonic);
+}
+
+/// Mark a software interrupt of IPL `ipl` on `cpu` as handled
+pub fn clear_softint_pending(cpu: *ke.Cpu, ipl: Ipl) void {
+    std.debug.assert(@intFromEnum(ipl) <= @intFromEnum(Ipl.Dispatch));
+    _ = cpu.pending_softints.bitReset(@intCast(@intFromEnum(ipl)), .monotonic);
+}
+
+/// Check whether a software interrupt of IPL `ipl` on `cpu` is pending
+pub fn is_softint_pending(cpu: *ke.Cpu, ipl: Ipl) bool {
+    std.debug.assert(@intFromEnum(ipl) <= @intFromEnum(Ipl.Dispatch));
+    const shift: u3 = @intCast(@intFromEnum(ipl));
+    const bit: u8 = @as(u8, 1) << shift;
+    return cpu.pending_softints.load(.monotonic) & bit != 0;
+}