Rearrange memory manager into two classes.

page_manager and memory_manager are now separate, and are also pre
allocated in the kernel so they don't have to allocate themselves.

src/kernel/main.cpp

@@ -42,7 +42,7 @@ kernel_main(popcorn_data *header)
 {
 	console cons = load_console(header);
 
-	memory_manager::create(
+	memory_initialize_managers(
 			header->memory_map,
 			header->memory_map_length,
 			header->memory_map_desc_size);

src/kernel/memory.cpp

@@ -3,8 +3,9 @@
 #include "memory.h"
 #include "memory_pages.h"
 
-memory_manager *memory_manager::s_instance = nullptr;
+memory_manager g_memory_manager;
 
-memory_manager::memory_manager(page_block *free, page_block *used, void *scratch, size_t scratch_len)
+memory_manager::memory_manager()
 {
+	kassert(this == &g_memory_manager, "Attempt to create another memory_manager.");
 }

src/kernel/memory.h

@@ -1,21 +1,23 @@
 #pragma once
+/// \file memory.h
+/// The block memory manager and related definitions.
 
 #include <stddef.h>
 
-struct page_block;
-
+/// Manager for allocation of virtual memory.
 class memory_manager
 {
 public:
+	memory_manager();
 
-	static void create(const void *memory_map, size_t map_length, size_t desc_length);
-	static memory_manager * get() { return s_instance; }
-
-private:
-	memory_manager(page_block *free, page_block *used, void *scratch, size_t scratch_len);
-
-	memory_manager() = delete;
 	memory_manager(const memory_manager &) = delete;
 
-	static memory_manager * s_instance;
+private:
+	friend class page_manager;
 };
+
+extern memory_manager g_memory_manager;
+
+/// Bootstrap the memory managers.
+void memory_initialize_managers(const void *memory_map, size_t map_length, size_t desc_length);
+

src/kernel/memory_bootstrap.cpp

@@ -227,7 +227,7 @@ gather_block_lists(
 }
 
 void
-memory_manager::create(const void *memory_map, size_t map_length, size_t desc_length)
+memory_initialize_managers(const void *memory_map, size_t map_length, size_t desc_length)
 {
 	console *cons = console::get();
 

src/kernel/memory_pages.cpp

@@ -1,13 +1,23 @@
+#include "assert.h"
 #include "console.h"
 #include "memory_pages.h"
 
+page_manager g_page_manager;
+
+page_manager::page_manager() :
+	m_free(nullptr),
+	m_used(nullptr),
+	m_pool(nullptr)
+{
+	kassert(this == &g_page_manager, "Attempt to create another page_manager.");
+}
+
+
 page_block *
 page_block::list_consolidate()
 {
-	page_block *cur = this;
 	page_block *freed_head = nullptr, **freed = &freed_head;
-
-	while (cur) {
+	for (page_block *cur = this; cur; cur = cur->next) {
 		page_block *next = cur->next;
 
 		if (next && cur->flags == next->flags &&
@@ -21,8 +31,6 @@ page_block::list_consolidate()
 			freed = &next->next;
 			continue;
 		}
-
-		cur = next;
 	}
 
 	return freed_head;

src/kernel/memory_pages.h

@@ -1,25 +1,51 @@
 #pragma once
 /// \file memory_pages.h
-/// Structures related to handling memory paging.
+/// The page memory manager and related definitions.
 
 #include <stdint.h>
 
 #include "kutil/enum_bitfields.h"
 
+class page_block;
+
+
+/// Manager for allocation of physical pages.
+class page_manager
+{
+public:
+	page_manager();
+
+	page_manager(const page_manager &) = delete;
+
+private:
+	friend void memory_initialize_managers(const void *, size_t, size_t);
+
+	/// Set up the memory manager from bootstraped memory
+	static void init(page_block *free, page_block *used, uint64_t scratch);
+
+	/// Initialize the virtual memory manager based on this object's state
+	void init_memory_manager();
+
+	page_block *m_free; ///< Free pages list
+	page_block *m_used; ///< In-use pages list
+	page_block *m_pool; ///< Cache of unused page_block structs
+};
+
+/// Global page manager.
+extern page_manager g_page_manager;
+
+
 /// Flags used by `page_block`.
 enum class page_block_flags : uint32_t
 {
-	// Not a flag value, but for comparison
-	free         = 0x00000000,
+	free         = 0x00000000,  ///< Not a flag, value for free memory
+	used         = 0x00000001,  ///< Memory is in use
+	mapped       = 0x00000002,  ///< Memory is mapped to virtual address
+	pending_free = 0x00000004,  ///< Memory should be freed
 
-	used         = 0x00000001,
-	mapped       = 0x00000002,
-	pending_free = 0x00000004,
-
-	nonvolatile  = 0x00000010,
-	acpi_wait    = 0x00000020,
-
-	permanent    = 0x80000000,
+	nonvolatile  = 0x00000010,  ///< Memory is non-volatile storage
+	acpi_wait    = 0x00000020,  ///< Memory should be freed after ACPI init
+	permanent    = 0x80000000,  ///< Memory is permanently unusable
 
 	max_flags
 };
@@ -67,6 +93,7 @@ struct page_table_indices
 	uint64_t index[4]; ///< Indices for each level of tables.
 };
 
+
 /// Calculate a page-aligned address.
 /// \arg p    The address to align.
 /// \returns  The next page-aligned address _after_ `p`.