First pass at vm_space (address_manager replacement)

src/libraries/kutil/include/kutil/avl_tree.h

@@ -0,0 +1,172 @@
+#pragma once
+/// \file avl_tree.h
+/// Templated container class for an AVL tree
+
+#include <stdint.h>
+#include "kutil/assert.h"
+
+namespace kutil {
+
+template <typename T> class avl_tree;
+
+
+/// A node in a `avl_tree<T>`
+template <typename T>
+class avl_node :
+	public T
+{
+public:
+	using item_type = T;
+	using node_type = avl_node<T>;
+
+	/// Dereference operator. Helper to cast this node to the contained type.
+	/// \returns  A pointer to the node, cast to T*.
+	inline item_type & operator*() { return *this; }
+
+	/// Dereference operator. Helper to cast this node to the contained type.
+	/// \returns  A pointer to the node, cast to T*.
+	inline const item_type & operator*() const { return *this; }
+
+	/// Cast operator. Helper to cast this node to the contained type.
+	/// \returns  A reference to the node, cast to T&.
+	inline operator item_type& () { return *this; }
+
+	/// Cast operator. Helper to cast this node to the contained type.
+	/// \returns  A reference to the node, cast to const T&.
+	inline operator const item_type& () { return *this; }
+
+	/// Helper to cast this node to the contained type.
+	/// \returns  A reference to the node, cast to const T&.
+	inline const item_type& item() const { return *this; }
+
+	/// Helper to cast this node to the contained type.
+	/// \returns  A reference to the node, cast to T&.
+	inline item_type& item() { return *this; }
+
+	/// Accessor for the left child.
+	/// \returns  A pointer to the left child, or nullptr.
+	inline node_type * left() { return m_left; }
+
+	/// Accessor for the left child.
+	/// \returns  A pointer to the left child, or nullptr.
+	inline const node_type * left() const { return m_left; }
+
+	/// Accessor for the right child.
+	/// \returns  A pointer to the right child, or nullptr.
+	inline node_type * right() { return m_right; }
+
+	/// Accessor for the right child.
+	/// \returns  A pointer to the right child, or nullptr.
+	inline const node_type * right() const { return m_right; }
+
+private:
+	friend class avl_tree<T>;
+
+	inline static int height(node_type *l) { return (l ? l->m_height : 0); }
+
+	// Update this node's height and return its new balance factor
+	inline int update_height()
+	{
+		int left = height(m_left);
+		int right = height(m_right);
+		m_height = std::max(left, right) + 1;
+		return left - right;
+	}
+
+	int bias(node_type *addend)
+	{
+		const item_type &this_item = *this;
+		const item_type &that_item = *addend;
+		if (that_item < this_item)
+			return -1;
+		else if (that_item > this_item)
+			return 1;
+
+		kassert(false, "Equal items not allowed in AVL tree");
+		return 0;
+	}
+
+	static node_type * rotate_right(node_type *existing)
+	{
+		node_type *root = existing->m_left;
+		node_type *left = root->m_right;
+
+		root->m_right = existing;
+		existing->m_left = left;
+
+		existing->update_height();
+		root->update_height();
+
+		return root;
+	}
+
+	static node_type * rotate_left(node_type *existing)
+	{
+		node_type *root = existing->m_right;
+		node_type *right = root->m_left;
+
+		root->m_left = existing;
+		existing->m_right = right;
+
+		existing->update_height();
+		root->update_height();
+
+		return root;
+	}
+
+	static node_type * insert(node_type *existing, node_type *addend)
+	{
+		if (existing == nullptr)
+			return addend;
+
+		if (existing->compare(addend) < 0)
+			existing->m_left = insert(existing->m_left, addend);
+		else
+			existing->m_right = insert(existing->m_right, addend);
+
+		int balance = existing->update_height();
+		if (balance > 1) {
+			// Left-heavy
+			if (existing->m_left->compare(addend) < 0) {
+				// Left Left
+				return rotate_right(existing);
+			} else {
+				// Left Right
+				existing->m_left = rotate_left(existing->m_left);
+				return rotate_right(existing);
+			}
+		} else if (balance < -1) {
+			// Right-heavy
+			if (existing->m_right->compare(addend) > 0) {
+				// Right Right
+				return rotate_left(existing);
+			} else {
+				// Right Left
+				existing->m_right = rotate_right(existing->m_right);
+				return rotate_left(existing);
+			}
+		}
+
+		return existing;
+	}
+
+	int m_height;
+	node_type *m_left;
+	node_type *m_right;
+};
+
+template <typename T>
+class avl_tree
+{
+public:
+	using item_type = T;
+	using node_type = avl_node<T>;
+
+	inline void insert(node_type *addend) { m_root = node_type::insert(m_root, addend); }
+	inline node_type * root() { return m_root; }
+
+private:
+	node_type *m_root;
+};
+
+} // namespace kutil

src/libraries/kutil/include/kutil/vm_space.h

@@ -0,0 +1,74 @@
+#pragma once
+/// \file vm_range.h
+/// Structure for tracking a range of virtual memory addresses
+
+#include <stdint.h>
+#include "kutil/allocator.h"
+#include "kutil/avl_tree.h"
+#include "kutil/slab_allocator.h"
+
+namespace kutil {
+
+enum class vm_state : uint8_t {
+	unknown,
+	none,
+	reserved,
+	committed,
+	mapped
+};
+
+struct vm_range
+{
+	uintptr_t address;
+	size_t size;
+	vm_state state;
+
+	inline uintptr_t end() const { return address + size; }
+	inline int compare(const vm_range *other) const {
+		return other->address - address;
+	}
+};
+
+class vm_space
+{
+public:
+	vm_space(uintptr_t start, size_t size, kutil::allocator &alloc);
+
+	/// Reserve a section of address space.
+	/// \arg start  Starting address of reservaion, or 0 for any address
+	/// \arg size   Size of reservation in bytes
+	/// \returns  The address of the reservation, or 0 on failure
+	uintptr_t reserve(uintptr_t start, size_t size);
+
+	/// Unreserve (and uncommit, if committed) a section of address space.
+	/// \arg start  Starting address of reservaion
+	/// \arg size   Size of reservation in bytes
+	void unreserve(uintptr_t start, size_t size);
+
+	/// Mark a section of address space as committed.
+	/// \arg start  Starting address of reservaion
+	/// \arg size   Size of reservation in bytes
+	/// \returns  The address of the reservation, or 0 on failure
+	uintptr_t commit(uintptr_t start, size_t size);
+
+	/// Mark a section of address space as uncommitted, but still reserved.
+	/// \arg start  Starting address of reservaion
+	/// \arg size   Size of reservation in bytes
+	void uncommit(uintptr_t start, size_t size);
+
+	/// Check the state of the given address.
+	/// \arg addr  The address to check
+	/// \returns   The state of the memory if known, or 'unknown'
+	vm_state get(uintptr_t addr);
+
+private:
+	using node_type = kutil::avl_node<vm_range>;
+	using tree_type = kutil::avl_tree<vm_range>;
+
+	node_type * split_out(node_type* node, uintptr_t start, size_t size, vm_state state);
+
+	slab_allocator<node_type> m_alloc;
+	tree_type m_ranges;
+};
+
+} // namespace kutil

src/libraries/kutil/vm_space.cpp

@@ -0,0 +1,136 @@
+#include <algorithm>
+#include "kutil/logger.h"
+#include "kutil/vm_space.h"
+
+namespace kutil {
+
+using node_type = kutil::avl_node<vm_range>;
+
+
+vm_space::vm_space(uintptr_t start, size_t size, allocator &alloc) :
+	m_alloc(alloc)
+{
+	node_type *node = m_alloc.pop();
+	node->address = start;
+	node->size = size;
+	node->state = vm_state::none;
+	m_ranges.insert(node);
+
+	log::info(logs::vmem, "Creating address space from %016llx-%016llx",
+			start, start+size);
+}
+
+inline static bool
+overlaps(node_type *node, uintptr_t start, size_t size)
+{
+	return start <= node->end() &&
+		   (start + size) >= node->address;
+}
+
+static node_type *
+find_overlapping(node_type *from, uintptr_t start, size_t size)
+{
+	while (from) {
+		if (overlaps(from, start, size))
+			return from;
+
+		from = start < from->address ?
+			from->left() :
+			from->right();
+	}
+
+	return nullptr;
+}
+
+node_type *
+vm_space::split_out(node_type *node, uintptr_t start, size_t size, vm_state state)
+{
+	// No cross-boundary splits allowed for now
+	bool contained = 
+		start >= node->address &&
+		start+size <= node->end();
+
+	kassert(contained,
+		"Tried to split an address range across existing boundaries");
+	if (!contained)
+		return nullptr;
+
+	vm_state old_state = node->state;
+	if (state == old_state)
+		return node;
+
+	log::debug(logs::vmem, "Splitting out region %016llx-%016llx[%d] from %016llx-%016llx[%d]",
+			start, start+size, state, node->address, node->end(), old_state);
+
+	if (node->address < start) {
+		// Split off rest into new node
+		size_t leading = start - node->address;
+
+		node_type *next = m_alloc.pop();
+		next->state = state;
+		next->address = start;
+		next->size = node->size - leading;
+		node->size = leading;
+
+		m_ranges.insert(next);
+		node = next;
+	} else {
+		// TODO: check if this can merge with prev node
+	}
+
+	if (node->end() > start + size) {
+		// Split off remaining into new node
+		size_t trailing =  node->size - size;
+		node->size -= trailing;
+
+		node_type *next = m_alloc.pop();
+		next->state = old_state;
+		next->address = node->end();
+		next->size = trailing;
+
+		m_ranges.insert(next);
+	} else {
+		// TODO: check if this can merge with next node
+	}
+
+	return node;
+}
+
+uintptr_t
+vm_space::reserve(uintptr_t start, size_t size)
+{
+	log::debug(logs::vmem, "Reserving region %016llx-%016llx", start, start+size);
+
+	node_type *node = find_overlapping(m_ranges.root(), start, size);
+	if (!node || node->state != vm_state::none)
+		return 0;
+
+	node = split_out(node, start, size, vm_state::reserved);
+	return node ? start : 0;
+}
+
+void
+vm_space::unreserve(uintptr_t start, size_t size)
+{
+}
+
+uintptr_t
+vm_space::commit(uintptr_t start, size_t size)
+{
+	return 0;
+}
+
+void
+vm_space::uncommit(uintptr_t start, size_t size)
+{
+}
+
+
+vm_state
+vm_space::get(uintptr_t addr)
+{
+	node_type *node = find_overlapping(m_ranges.root(), addr, 0);
+	return node ? node->state : vm_state::unknown;
+}
+
+} // namespace kutil