Optimize PageTableManager and associated VMM.

    - Changed overall page table behavior to no longer use C bits
      in page table entries.  Instead, individual blocks mark
      pages as dirty based on stores during page faults.  Initially
      all writable pages are marked read-only until the first store
      to it.  At that time the block gets an exception and changes
      the permission on the page table entry to writable and marks
      its own SPTE to dirty.

    - Greatly reduced the number of tlbie's and page table accesses.
      Accomplished this by:
          * Skipping many of the page table manipulations, such as
	    LRU updates, when the PTE is invalid.
	  * Converting most of the previously general-case of
	    "Modifying a PTE" to specific cases such as "Resetting
	    the Reference Bit" and "Modifying the SW field".

    - Fixed the LRU-flush algorithm so that it is O(n) instead of
      O(n^2), where n = size of page table.

Change-Id: I2520fa88970fd7f656e6348bf6b34d5db82fd3db
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/892
Tested-by: Jenkins Server
Reviewed-by: Douglas R. Gilbert <dgilbert@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/include/kernel/block.H b/src/include/kernel/block.H
index 48e27b803..5d80ea7c6 100644
--- a/src/include/kernel/block.H
+++ b/src/include/kernel/block.H
@@ -104,6 +104,7 @@ class Block
          *
          * @param[in] i_task - Task causing the page fault.
          * @param[in] i_addr - Effective address accessed to cause fault.
+         * @param[in] i_store - The fault was due to a store.
          *
          * @return true - Page fault was successfully handled.
          *
@@ -114,14 +115,14 @@ class Block
          * 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);
+        bool handlePageFault(task_t* i_task, uint64_t i_addr, bool i_store);
 
         /**
          * @brief Locate the physical address of the given virtual address
          *
          * @param[in] i_vaddr virtual address
          *
-         * @return the physical address bound to the virtual address, 
+         * @return the physical address bound to the virtual address,
          *         -EFAULT if not found @see errno.h
          */
         uint64_t findPhysicalAddress(uint64_t i_vaddr) const;
@@ -202,7 +203,7 @@ class Block
          *          and a size of memory needing updated permissions
          * @param i_va[in] - virtual address of the beginning of the
          *           pages that need updating.
-         * @param i_size[in] - range of memory that needs updating 
+         * @param i_size[in] - range of memory that needs updating
          *          if i_size equals 0 then we only need to update an
          *          individual page.
          * @param i_access_type[in] - type of permission to set using