[kernel] Init the boot percpu data

Author: bherrera

slipstream/kernel/kernel/PerCpu.zig

@@ -0,0 +1,46 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+const std = @import("std");
+const assert = @import("assert.zig");
+const lazy_init = @import("lazy_init");
+const Scheduler = @import("Scheduler.zig");
+const defines = @import("../arch/x86/defines.zig");
+const arch = @import("arch/mp.zig").Impl;
+const cpu = @import("cpu.zig");
+const PerCpu = @This();
+
+const CpuNum = cpu.CpuNum;
+
+scheduler: Scheduler,
+
+// The percpu for the boot processor.
+var boot_processor: lazy_init.LazyInitChecked(PerCpu) align(defines.max_cache_line) linksection(".data.cpu_align_exclusive") = undefined;
+
+// Pointer to heap memory allocated for additional percpu instances.
+var secondary_processors: *PerCpu = null;
+
+// Translates from CPU number to percpu instance. Some or all instances
+// of percpu may be discontiguous.
+var processor_index: []*PerCpu = undefined;
+
+// Number of percpu entries.
+var processor_count: usize = 1;
+
+pub fn init(cpu_num: CpuNum) PerCpu {
+    return PerCpu{ .scheduler = Scheduler{ .this_cpu = cpu_num } };
+}
+
+/// Initialize the boot processor's per-CPU data
+pub fn initBoot() void {
+    _ = boot_processor.initialize(init(0));
+    // Install a pointer to the boot CPU's high-level percpu struct in its low-level percpu struct.
+    arch.setupPercpu(0, boot_processor.get());
+}
+
+// Returns a reference to the percpu instance for given CPU number.
+pub fn get(cpu_num: CpuNum) *PerCpu {
+    assert.debug_assert(@src(), cpu_num < processor_count);
+    return processor_index[cpu_num];
+}

slipstream/kernel/kernel/Scheduler.zig

@@ -0,0 +1,17 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+const cpu = @import("cpu.zig");
+const Scheduler = @This();
+
+const CpuNum = cpu.CpuNum;
+
+// The CPU this scheduler instance is associated with.
+// NOTE: This member is not initialized to prevent clobbering the value set
+// by sched_early_init(), which is called before the global ctors that
+// initialize the rest of the members of this class.
+// TODO(eieio): Figure out a better long-term solution to determine which
+// CPU is associated with each instance of this class. This is needed by
+// non-static methods that are called from arbitrary CPUs, namely Insert().
+this_cpu: CpuNum,

slipstream/kernel/kernel/Thread.zig

@@ -3,23 +3,37 @@
 //! found in the LICENSE file.
 
 const std = @import("std");
+const dbl = @import("dbl");
+const lazy_init = @import("lazy_init");
+const assert = @import("assert.zig");
+const arch = @import("arch/mp.zig").Impl;
+const spin_lock = @import("spin_lock.zig");
+const PerCpu = @import("PerCpu.zig");
+const Thread = @This();
 
-const arch = @import("../arch/x86/mp.zig");
+const SpinLock = spin_lock.SpinLock;
+const List = dbl.DoublyLinkedList(*Thread);
 
-const debug_assert = @import("assert.zig").debug_assert;
+list_lock: SpinLock,
+
+var thread_list: lazy_init.LazyInitDefault(List) = undefined;
+
+pub fn getListLock() *SpinLock {
+    return &Thread.list_lock;
+}
 
 /// Initialize threading system
 ///
 /// This function is called once, from kmain()
 pub fn threadInitEarly() void {
-    debug_assert(@src(), arch.currCpuNum() == 0);
+    assert.debug_assert(@src(), arch.currCpuNum() == 0);
 
     // Initialize the thread list. This needs to be done manually now, since initial thread code
     // manipulates the list before global constructors are run.
-    //threadList.init();
+    _ = thread_list.initialize(List{});
 
     // Init the boot percpu data.
-    //percpu.initBoot();
+    PerCpu.initBoot();
 
     // Create a thread to cover the current running state
     //const t = &percpu.get(0).idle_power_thread.thread;

slipstream/kernel/top/main.zig

@@ -3,7 +3,8 @@
 //! found in the LICENSE file.
 
 const Init = @import("../lib/init/init.zig");
-const Thread = @import("../kernel/Thread.zig");
+
+const threadInitEarly = @import("../kernel/Thread.zig").threadInitEarly;
 
 // saved boot arguments from whoever loaded the system
 var lk_boot_args: [4]u64 = undefined;
@@ -17,7 +18,7 @@ export fn lk_main(arg0: u64, arg1: u64, arg2: u64, arg3: u64) align(16) callconv
     lk_boot_args[3] = arg3;
 
     //Init.initLevelAll(.{ .primary_cpu = true });
-    Thread.threadInitEarly();
+    threadInitEarly();
 
     //Init.initLevelAll(.{ .secondary_cpus = true });
 }