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https://github.com/rdmsr/zag.git
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Loïc Grégoire
107 lines
3.0 KiB
Zig
107 lines
3.0 KiB
Zig
const std = @import("std");
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const b = @import("base");
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const ke = b.ke;
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const ki = ke.private;
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/// Interrupt priority level (IPL)
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pub const Ipl = enum(u8) {
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/// All interrupts enabled.
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Passive = 0,
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/// Preemption disabled.
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Dispatch = 1,
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/// Device interrupts disabled.
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Device = 13,
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/// All interrupts disabled.
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High = 15,
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pub fn get_max_software() Ipl {
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return .Dispatch;
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}
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};
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/// Bitmask of pending software interrupts on this CPU.
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const pending_softints = ke.CpuLocal(std.atomic.Value(u8), .init(0));
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/// Raise IPL to `new`.
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/// Panics if the current IPL is higher than requested.
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pub fn raise(new: Ipl) Ipl {
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const ints = ki.impl.disable_interrupts();
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var cpu = ke.curcpu();
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const old = cpu.ipl;
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if (@intFromEnum(new) < @intFromEnum(old)) {
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ke.panic("ke.ipl.raise(): Target IPL ({}) is lower than current IPL ({})\n", .{ new, old });
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}
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if (@intFromEnum(new) > @intFromEnum(Ipl.get_max_software())) {
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ki.impl.set_hardware_ipl(new);
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}
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cpu.ipl = new;
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ki.impl.restore_interrupts(ints);
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return old;
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}
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/// Lower IPL to `new`.
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/// Panics if the current IPL is lower than requested.
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pub fn lower(new: Ipl) void {
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const ints = ki.impl.disable_interrupts();
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var cpu = ke.curcpu();
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const old = cpu.ipl;
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if (@intFromEnum(new) > @intFromEnum(old)) {
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ke.panic("ke.ipl.lower(): Target IPL ({}) is higher than current IPL ({})\n", .{ new, old });
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}
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if (@intFromEnum(new) <= @intFromEnum(Ipl.get_max_software()) and @intFromEnum(old) > @intFromEnum(Ipl.get_max_software())) {
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ki.impl.set_hardware_ipl(.Passive);
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}
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cpu.ipl = new;
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ki.impl.restore_interrupts(ints);
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if (@intFromEnum(new) < @intFromEnum(Ipl.Dispatch) and is_softint_pending(.Dispatch)) {
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ki.dpc.dispatch(cpu);
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}
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}
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comptime {
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if (!@hasDecl(ki.impl, "set_hardware_ipl")) @compileError("impl must provide set_hardware_ipl()");
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}
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/// Set the hardware IPL to `new`.
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pub fn set_hardware(new: Ipl) Ipl {
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var cpu = ke.curcpu();
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const old = cpu.ipl;
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cpu.ipl = new;
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ki.impl.set_hardware_ipl(new);
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return old;
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}
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/// Mark a software interrupt of IPL `ipl` on `cpu` as pending.
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pub fn set_softint_pending(cpu: *ke.Cpu, ipl: Ipl) void {
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std.debug.assert(@intFromEnum(ipl) <= @intFromEnum(Ipl.Dispatch));
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_ = pending_softints.remote(cpu).bitSet(@intCast(@intFromEnum(ipl)), .monotonic);
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}
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/// Mark a software interrupt of IPL `ipl` on `cpu` as handled.
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pub fn clear_softint_pending(cpu: *ke.Cpu, ipl: Ipl) void {
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std.debug.assert(@intFromEnum(ipl) <= @intFromEnum(Ipl.Dispatch));
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_ = pending_softints.remote(cpu).bitReset(@intCast(@intFromEnum(ipl)), .monotonic);
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}
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/// Check whether a software interrupt of IPL `ipl` on the current CPU is pending.
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pub fn is_softint_pending(ipl: Ipl) bool {
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std.debug.assert(@intFromEnum(ipl) <= @intFromEnum(Ipl.Dispatch));
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const shift: u3 = @intCast(@intFromEnum(ipl));
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const bit: u8 = @as(u8, 1) << shift;
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return pending_softints.local().load(.monotonic) & bit != 0;
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}
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