Kernel: Move deferred call code into separate DeferredCallPool class

This allows us to share this code between the x86_64 and aarch64 build.

Kernel/Arch/DeferredCallPool.cpp

@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2020, Tom <tomut@yahoo.com>
+ * Copyright (c) 2023, Timon Kruiper <timonkruiper@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/Arch/DeferredCallEntry.h>
+#include <Kernel/Arch/DeferredCallPool.h>
+#include <Kernel/Heap/kmalloc.h>
+
+namespace Kernel {
+
+void DeferredCallPool::init()
+{
+    size_t pool_count = sizeof(m_deferred_call_pool) / sizeof(m_deferred_call_pool[0]);
+    for (size_t i = 0; i < pool_count; i++) {
+        auto& entry = m_deferred_call_pool[i];
+        entry.next = i < pool_count - 1 ? &m_deferred_call_pool[i + 1] : nullptr;
+        new (entry.handler_storage) DeferredCallEntry::HandlerFunction;
+        entry.was_allocated = false;
+    }
+    m_pending_deferred_calls = nullptr;
+    m_free_deferred_call_pool_entry = &m_deferred_call_pool[0];
+}
+
+void DeferredCallPool::return_to_pool(DeferredCallEntry* entry)
+{
+    VERIFY(!entry->was_allocated);
+
+    entry->handler_value() = {};
+
+    entry->next = m_free_deferred_call_pool_entry;
+    m_free_deferred_call_pool_entry = entry;
+}
+
+DeferredCallEntry* DeferredCallPool::get_free()
+{
+    if (m_free_deferred_call_pool_entry) {
+        // Fast path, we have an entry in our pool
+        auto* entry = m_free_deferred_call_pool_entry;
+        m_free_deferred_call_pool_entry = entry->next;
+        VERIFY(!entry->was_allocated);
+        return entry;
+    }
+
+    auto* entry = new DeferredCallEntry;
+    new (entry->handler_storage) DeferredCallEntry::HandlerFunction;
+    entry->was_allocated = true;
+    return entry;
+}
+
+void DeferredCallPool::execute_pending()
+{
+    if (!m_pending_deferred_calls)
+        return;
+    auto* pending_list = m_pending_deferred_calls;
+    m_pending_deferred_calls = nullptr;
+
+    // We pulled the stack of pending deferred calls in LIFO order, so we need to reverse the list first
+    auto reverse_list = [](DeferredCallEntry* list) -> DeferredCallEntry* {
+        DeferredCallEntry* rev_list = nullptr;
+        while (list) {
+            auto next = list->next;
+            list->next = rev_list;
+            rev_list = list;
+            list = next;
+        }
+        return rev_list;
+    };
+    pending_list = reverse_list(pending_list);
+
+    do {
+        pending_list->invoke_handler();
+
+        // Return the entry back to the pool, or free it
+        auto* next = pending_list->next;
+        if (pending_list->was_allocated) {
+            pending_list->handler_value().~Function();
+            delete pending_list;
+        } else
+            return_to_pool(pending_list);
+        pending_list = next;
+    } while (pending_list);
+}
+
+void DeferredCallPool::queue_entry(DeferredCallEntry* entry)
+{
+    entry->next = m_pending_deferred_calls;
+    m_pending_deferred_calls = entry;
+}
+
+}

Kernel/Arch/DeferredCallPool.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2020, Tom <tomut@yahoo.com>
+ * Copyright (c) 2023, Timon Kruiper <timonkruiper@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/Arch/DeferredCallEntry.h>
+
+namespace Kernel {
+
+class DeferredCallPool {
+public:
+    void init();
+    void execute_pending();
+    DeferredCallEntry* get_free();
+    void return_to_pool(DeferredCallEntry*);
+    void queue_entry(DeferredCallEntry*);
+
+private:
+    DeferredCallEntry* m_pending_deferred_calls; // in reverse order
+    DeferredCallEntry* m_free_deferred_call_pool_entry;
+    DeferredCallEntry m_deferred_call_pool[5];
+};
+
+}

Kernel/Arch/aarch64/Processor.cpp

@@ -91,6 +91,8 @@ void Processor::early_initialize(u32 cpu)
 
 void Processor::initialize(u32)
 {
+    m_deferred_call_pool.init();
+
     dmesgln("CPU[{}]: Supports {}", m_cpu, build_cpu_feature_names(m_features));
     dmesgln("CPU[{}]: Physical address bit width: {}", m_cpu, m_physical_address_bit_width);
     dmesgln("CPU[{}]: Virtual address bit width: {}", m_cpu, m_virtual_address_bit_width);
@@ -132,7 +134,7 @@ void Processor::do_leave_critical()
     VERIFY(m_in_critical > 0);
     if (m_in_critical == 1) {
         if (m_in_irq == 0) {
-            // FIXME: Call deferred_call_execute_pending()!
+            m_deferred_call_pool.execute_pending();
             VERIFY(m_in_critical == 1);
         }
         m_in_critical = 0;
@@ -402,6 +404,10 @@ void Processor::exit_trap(TrapFrame& trap)
     // FIXME: Figure out if we need prev_irq_level, see duplicated code in Kernel/Arch/x86/common/Processor.cpp
     m_in_irq = 0;
 
+    // Process the deferred call queue. Among other things, this ensures
+    // that any pending thread unblocks happen before we enter the scheduler.
+    m_deferred_call_pool.execute_pending();
+
     auto* current_thread = Processor::current_thread();
     if (current_thread) {
         auto& current_trap = current_thread->current_trap();
@@ -542,4 +548,17 @@ void Processor::set_thread_specific_data(VirtualAddress thread_specific_data)
     Aarch64::Asm::set_tpidr_el0(thread_specific_data.get());
 }
 
+void Processor::deferred_call_queue(Function<void()> callback)
+{
+    // NOTE: If we are called outside of a critical section and outside
+    // of an irq handler, the function will be executed before we return!
+    ScopedCritical critical;
+    auto& cur_proc = Processor::current();
+
+    auto* entry = cur_proc.m_deferred_call_pool.get_free();
+    entry->handler_value() = move(callback);
+
+    cur_proc.m_deferred_call_pool.queue_entry(entry);
+}
+
 }

Kernel/Arch/aarch64/Processor.h

@@ -11,6 +11,8 @@
 #include <AK/Function.h>
 #include <AK/Types.h>
 
+#include <Kernel/Arch/DeferredCallEntry.h>
+#include <Kernel/Arch/DeferredCallPool.h>
 #include <Kernel/Arch/ProcessorSpecificDataID.h>
 #include <Kernel/Arch/aarch64/CPUID.h>
 #include <Kernel/Arch/aarch64/Registers.h>
@@ -255,10 +257,7 @@ public:
         return Processor::current_id() == 0;
     }
 
-    static void deferred_call_queue(Function<void()> /* callback */)
-    {
-        TODO_AARCH64();
-    }
+    static void deferred_call_queue(Function<void()>);
 
     static u32 smp_wake_n_idle_processors(u32 wake_count);
 
@@ -282,6 +281,8 @@ private:
 
     void do_leave_critical();
 
+    DeferredCallPool m_deferred_call_pool {};
+
     u32 m_cpu;
     CPUFeature::Type m_features;
     u8 m_physical_address_bit_width;

Kernel/Arch/x86_64/Processor.cpp

@@ -626,7 +626,7 @@ UNMAP_AFTER_INIT void Processor::early_initialize(u32 cpu)
         g_total_processors.fetch_add(1u, AK::MemoryOrder::memory_order_acq_rel);
     }
 
-    deferred_call_pool_init();
+    m_deferred_call_pool.init();
 
     cpu_setup();
     gdt_init();
@@ -948,7 +948,7 @@ void Processor::exit_trap(TrapFrame& trap)
 
     // Process the deferred call queue. Among other things, this ensures
     // that any pending thread unblocks happen before we enter the scheduler.
-    deferred_call_execute_pending();
+    m_deferred_call_pool.execute_pending();
 
     auto* current_thread = Processor::current_thread();
     if (current_thread) {
@@ -1345,92 +1345,6 @@ void Processor::Processor::halt()
     halt_this();
 }
 
-UNMAP_AFTER_INIT void Processor::deferred_call_pool_init()
-{
-    size_t pool_count = sizeof(m_deferred_call_pool) / sizeof(m_deferred_call_pool[0]);
-    for (size_t i = 0; i < pool_count; i++) {
-        auto& entry = m_deferred_call_pool[i];
-        entry.next = i < pool_count - 1 ? &m_deferred_call_pool[i + 1] : nullptr;
-        new (entry.handler_storage) DeferredCallEntry::HandlerFunction;
-        entry.was_allocated = false;
-    }
-    m_pending_deferred_calls = nullptr;
-    m_free_deferred_call_pool_entry = &m_deferred_call_pool[0];
-}
-
-void Processor::deferred_call_return_to_pool(DeferredCallEntry* entry)
-{
-    VERIFY(m_in_critical);
-    VERIFY(!entry->was_allocated);
-
-    entry->handler_value() = {};
-
-    entry->next = m_free_deferred_call_pool_entry;
-    m_free_deferred_call_pool_entry = entry;
-}
-
-DeferredCallEntry* Processor::deferred_call_get_free()
-{
-    VERIFY(m_in_critical);
-
-    if (m_free_deferred_call_pool_entry) {
-        // Fast path, we have an entry in our pool
-        auto* entry = m_free_deferred_call_pool_entry;
-        m_free_deferred_call_pool_entry = entry->next;
-        VERIFY(!entry->was_allocated);
-        return entry;
-    }
-
-    auto* entry = new DeferredCallEntry;
-    new (entry->handler_storage) DeferredCallEntry::HandlerFunction;
-    entry->was_allocated = true;
-    return entry;
-}
-
-void Processor::deferred_call_execute_pending()
-{
-    VERIFY(m_in_critical);
-
-    if (!m_pending_deferred_calls)
-        return;
-    auto* pending_list = m_pending_deferred_calls;
-    m_pending_deferred_calls = nullptr;
-
-    // We pulled the stack of pending deferred calls in LIFO order, so we need to reverse the list first
-    auto reverse_list =
-        [](DeferredCallEntry* list) -> DeferredCallEntry* {
-        DeferredCallEntry* rev_list = nullptr;
-        while (list) {
-            auto next = list->next;
-            list->next = rev_list;
-            rev_list = list;
-            list = next;
-        }
-        return rev_list;
-    };
-    pending_list = reverse_list(pending_list);
-
-    do {
-        pending_list->invoke_handler();
-
-        // Return the entry back to the pool, or free it
-        auto* next = pending_list->next;
-        if (pending_list->was_allocated) {
-            pending_list->handler_value().~Function();
-            delete pending_list;
-        } else
-            deferred_call_return_to_pool(pending_list);
-        pending_list = next;
-    } while (pending_list);
-}
-
-void Processor::deferred_call_queue_entry(DeferredCallEntry* entry)
-{
-    VERIFY(m_in_critical);
-    entry->next = m_pending_deferred_calls;
-    m_pending_deferred_calls = entry;
-}
-
 void Processor::deferred_call_queue(Function<void()> callback)
 {
     // NOTE: If we are called outside of a critical section and outside
@@ -1438,10 +1352,10 @@ void Processor::deferred_call_queue(Function<void()> callback)
     ScopedCritical critical;
     auto& cur_proc = Processor::current();
 
-    auto* entry = cur_proc.deferred_call_get_free();
+    auto* entry = cur_proc.m_deferred_call_pool.get_free();
     entry->handler_value() = move(callback);
 
-    cur_proc.deferred_call_queue_entry(entry);
+    cur_proc.m_deferred_call_pool.queue_entry(entry);
 }
 
 UNMAP_AFTER_INIT void Processor::gdt_init()
@@ -1601,7 +1515,7 @@ void Processor::do_leave_critical()
     VERIFY(m_in_critical > 0);
     if (m_in_critical == 1) {
         if (m_in_irq == 0) {
-            deferred_call_execute_pending();
+            m_deferred_call_pool.execute_pending();
             VERIFY(m_in_critical == 1);
         }
         m_in_critical = 0;

Kernel/Arch/x86_64/Processor.h

@@ -12,6 +12,7 @@
 #include <AK/Types.h>
 
 #include <Kernel/Arch/DeferredCallEntry.h>
+#include <Kernel/Arch/DeferredCallPool.h>
 #include <Kernel/Arch/ProcessorSpecificDataID.h>
 #include <Kernel/Arch/x86_64/ASM_wrapper.h>
 #include <Kernel/Arch/x86_64/CPUID.h>
@@ -102,9 +103,7 @@ class Processor {
     bool m_in_scheduler;
     Atomic<bool> m_halt_requested;
 
-    DeferredCallEntry* m_pending_deferred_calls; // in reverse order
-    DeferredCallEntry* m_free_deferred_call_pool_entry;
-    DeferredCallEntry m_deferred_call_pool[5];
+    DeferredCallPool m_deferred_call_pool {};
 
     void* m_processor_specific_data[(size_t)ProcessorSpecificDataID::__Count];
 
@@ -122,12 +121,6 @@ class Processor {
     static void smp_broadcast_wait_sync(ProcessorMessage& msg);
     static void smp_broadcast_halt();
 
-    void deferred_call_pool_init();
-    void deferred_call_execute_pending();
-    DeferredCallEntry* deferred_call_get_free();
-    void deferred_call_return_to_pool(DeferredCallEntry*);
-    void deferred_call_queue_entry(DeferredCallEntry*);
-
     void cpu_detect();
     void cpu_setup();
 

Kernel/CMakeLists.txt

@@ -18,6 +18,7 @@ set(KERNEL_HEAP_SOURCES
 set(KERNEL_SOURCES
     AddressSanitizer.cpp
     Arch/PageFault.cpp
+    Arch/DeferredCallPool.cpp
     Bus/PCI/Controller/HostController.cpp
     Bus/PCI/Controller/MemoryBackedHostBridge.cpp
     Bus/PCI/Controller/VolumeManagementDevice.cpp