1 files changed, 161 insertions, 0 deletions
diff --git a/src/include/kernel/block.H b/src/include/kernel/block.H
new file mode 100644
index 000000000..1de1c1280
--- /dev/null
+++ b/src/include/kernel/block.H
@@ -0,0 +1,161 @@
+/** @file block.H
+ *  @brief Defines the implementation for the generic VMM block class.
+ */
+#ifndef __KERNEL_BLOCK_H
+#define __KERNEL_BLOCK_H
+
+#include <stdint.h>
+#include <kernel/task.H>
+#include <kernel/vmmmgr.H>
+
+class ShadowPTE;
+class Segment;
+
+/** @class Block
+ *  @brief Provides management of the memory pages associated with a block of
+ *         virtual memory.
+ *
+ *  This class is organized to be either an independent block (typically
+ *  managed by the Segment container in some way) or as a chain of blocks.
+ *
+ *  When the instance is assigned down-stream blocks, the instance will
+ *  forward requests that do not belong to it down the chain for handling
+ *  by a block responsible for the request.  Also, when used in this manner,
+ *  this block is responsible for the ownership of all down-stream blocks,
+ *  including calling their destructor when necessary.
+ *
+ *  There is currently no mechanism for dynamically removing blocks from the
+ *  chain.  The expectation is that all known use cases would suggest either
+ *  a fixed (increasing-only) chain or a known-sized array of blocks.
+ */
+class Block
+{
+    public:
+        /**
+         * @brief Constructor.
+         *
+         * @param[in] i_baseAddr - Base virtual Address of the block.
+         * @param[in] i_size - Size of the block (in bytes).
+         *
+         * Will allocate enough shadow PTEs to track pages in the block.
+         */
+        Block(uint64_t i_baseAddr, uint64_t i_size) :
+                iv_baseAddr(i_baseAddr), iv_size(i_size),
+                iv_parent(NULL), iv_nextBlock(NULL), iv_ptes(NULL)
+            { init(); };
+
+        /**
+         * @brief Destructor.
+         *
+         * Releases associated memory and down-stream blocks.
+         */
+        ~Block();
+
+        /**
+         * @brief Get the base address of this block.
+         * @return Base address (as uint64_t).
+         */
+        uint64_t getBaseAddress() const { return iv_baseAddr; };
+
+        /**
+         * @brief Determines if a virtual address is in the range of the block.
+         *
+         * @param[in] i_addr - The virtual address in question.
+         * @return true - Address is contained within the block.
+         * @return false - Address is not contained within the block.
+         */
+        bool isContained(uint64_t i_addr) const
+                { return (i_addr >= iv_baseAddr) &&
+                         (i_addr < iv_baseAddr + iv_size); };
+
+        /**
+         * @brief Responsible for handling page faults within the block [chain].
+         *
+         * @param[in] i_task - Task causing the page fault.
+         * @param[in] i_addr - Effective address accessed to cause fault.
+         *
+         * @return true - Page fault was successfully handled.
+         *
+         * If the page fault is not successfully handled the expectation is
+         * that the VMM will perform appropriate action, such as killing the
+         * task.
+         *
+         * If the address is not within this block, the block will attempt to
+         * make calls down the block-chain if it exists.
+         */
+        bool handlePageFault(task_t* i_task, uint64_t i_addr);
+
+        friend class Segment;
+        friend class BaseSegment;
+        friend class StackSegment;
+
+    protected:
+        /**
+         * @brief Assign a segment to a parent relationship to this block.
+         *
+         * @param[in] i_parent - The segment to assign as a parent.
+         */
+        void setParent(Segment* i_parent) { iv_parent = i_parent; };
+
+        /**
+         * @brief Add a block to the end of this block-chain.
+         *
+         * @param[in] i_block - The block tp append.
+         */
+        void appendBlock(Block* i_block)
+                {
+                    if (NULL == iv_nextBlock) iv_nextBlock = i_block;
+                    else iv_nextBlock->appendBlock(i_block);
+                }
+
+        /**
+         * @brief Set up a virtual-physical mapping for a static page.
+         *
+         * @param[in] i_vAddr - The virtual address of the page.
+         * @param[in] i_pAddr - The physical address of the page.
+         * @param[in] i_access - The permissions of the page.
+         */
+        void setPhysicalPage(uint64_t i_vAddr, uint64_t i_pAddr,
+                             VmmManager::ACCESS_TYPES i_access);
+
+    private:
+            /** Base address of the block */
+        const uint64_t iv_baseAddr;
+            /** Size of the block */
+        const uint64_t iv_size;
+
+            /** Pointer to the parent (containing) segment. */
+        Segment* iv_parent;
+            /** Pointer to the next block in the chain. */
+        Block* iv_nextBlock;
+
+            /** Pointer to the Shadow PTE entries. */
+        ShadowPTE* iv_ptes;
+
+        /**
+         * @brief Finish initialization of block.
+         *
+         * Construct ShadowPTE entries.
+         *
+         * This is defined as a separate function to reduce the code
+         * footprint of the class constructors.  GCC emits an "in-charge" and
+         * "not-in-charge" version of each constructor, so put as much
+         * common code into an init function.
+         */
+        void init();
+
+        /**
+         * @brief Find the Shadow PTE for a virtual address.
+         *
+         * @param[in] i_addr - The virtual address to find a page for.
+         * @note This function does no bounds checking.
+         */
+        ShadowPTE* getPTE(uint64_t i_addr) const;
+
+
+        Block(const Block&);  // prohibit copy.
+        Block& operator=(const Block&);  // prohibit assignment.
+
+};
+
+#endif