filled out more of mm_bootstrap() including initializing the free page linked list

git-svn-id: svn://anubis/hos/trunk@34 5b3e749e-e535-0410-8002-a9bb6afbdfca

kernel/boot/k_bootstrap.cc

@@ -29,7 +29,7 @@ u32_t k_bootstrap(mb_info_t * mb_info, u32_t mb_magic)
         k_early_panic("No memory map provided by bootloader!");
     }
 
-    mb_mmap_t * mmap = (mb_mmap_t *) (mb_info->mmap_addr + HOS_KERNEL_OFFSET - 4);
+    mb_mmap_t * mmap = (mb_mmap_t *) (mb_info->mmap_addr + KERNEL_OFFSET - 4);
     for (unsigned int sz = 0; sz < mb_info->mmap_length; sz += mmap->size + 4)
     {
         mm_record_mmap_entry(mmap);

kernel/include/hos_defines.h

@@ -6,23 +6,28 @@
 extern "C" {
 #endif
 
-#define HOS_KERNEL_OFFSET       0xE0000000
+#define KERNEL_OFFSET           0xE0000000
 
 #define PAGE_LOG_SIZE           12
 #define PAGE_SIZE               (1 << PAGE_LOG_SIZE)
 #define PAGE_HIGH_MASK          (0xFFFFFFFFu << PAGE_LOG_SIZE)
 #define PAGE_LOW_MASK           (0xFFFFFFFFu >> (32 - PAGE_LOG_SIZE))
 
-#define CONSOLE_MEMORY          (HOS_KERNEL_OFFSET + 0xB8000)
+#define CONSOLE_MEMORY          (KERNEL_OFFSET + 0xB8000)
 
 extern  u8_t    _code;
 extern  u8_t    _data;
 extern  u8_t    _bss;
 extern  u8_t    _end;
 
-#define KERNEL_PHYSICAL_ADDRESS ((&_code) - HOS_KERNEL_OFFSET)
+#define KERNEL_CODE (&_code)
-#define KERNEL_VIRTUAL_ADDRESS  (&_code)
+#define KERNEL_DATA (&_data)
-#define KERNEL_SIZE             ((&_end) - (&_code))
+#define KERNEL_BSS  (&_bss)
+#define KERNEL_END  (&_end)
+
+#define KERNEL_PHYSICAL_ADDRESS ((u32_t)(KERNEL_CODE - KERNEL_OFFSET))
+#define KERNEL_VIRTUAL_ADDRESS  ((u32_t)KERNEL_CODE)
+#define KERNEL_SIZE             ((u32_t)(KERNEL_END - KERNEL_CODE))
 
 #ifdef __cplusplus
 }

kernel/mm/mm.cc

@@ -1,4 +1,6 @@
 
+#include <stddef.h>
+
 #include "mm.h"
 #include "boot/k_early_panic.h"
 
@@ -10,6 +12,8 @@ pagedirectory_t page_directory __attribute__ ((aligned (4096)));
 
 static mm_mem_range_t mm_mmap_entries[MM_MAX_MMAP_ENTRIES];
 static int mm_mmap_num_entries = 0;
+static int mm_num_free_pages = 0;
+u32_t * mm_free_page_ptr = NULL;
 
 /**************************************************************************
  * This function is run in segmented memory before paging is in effect.   *
@@ -38,6 +42,8 @@ void mm_record_mmap_entry(mb_mmap_t * mmap)
  *************************************************************************/
 void mm_bootstrap()
 {
+    u32_t max_ram_address = KERNEL_PHYSICAL_ADDRESS + KERNEL_SIZE - 1;
+
     if (mm_mmap_num_entries < 1)
     {
         k_early_panic("No mmap entries read from bootloader!");
@@ -45,12 +51,58 @@ void mm_bootstrap()
 
     for (int mmap_idx = 0; mmap_idx < mm_mmap_num_entries; mmap_idx++)
     {
+        u32_t base_address = mm_mmap_entries[mmap_idx].base;
+        if (base_address & PAGE_LOW_MASK)
+        {
+            /* start of this mmap range is not page-aligned */
+            base_address = (base_address & PAGE_HIGH_MASK) + PAGE_SIZE;
+        }
+        u32_t address_limit = mm_mmap_entries[mmap_idx].base +
+                              mm_mmap_entries[mmap_idx].length;
+        if (address_limit & PAGE_LOW_MASK)
+        {
+            /* end of this mmap range is not page-aligned */
+            address_limit &= PAGE_HIGH_MASK;
+        }
+
+        /* record the highest RAM address found */
+        if ((address_limit - 1) > max_ram_address)
+        {
+            max_ram_address = (address_limit - 1);
+        }
+
+        /*
+         * loop through every page in the mmap range and add
+         * pages into the free page linked list
+         */
+        u32_t * last_page = NULL;
+        while (base_address < address_limit)
+        {
+            /* check to make sure the RAM page isn't overlapping the kernel */
+            if (   base_address + PAGE_SIZE <= KERNEL_PHYSICAL_ADDRESS
+                && base_address >= KERNEL_PHYSICAL_ADDRESS + KERNEL_SIZE )
+            {
+                /* we found a page to add to the free list */
+                u32_t * page_virtual_address =
+                    (u32_t *)(base_address + KERNEL_OFFSET);
+                *page_virtual_address = 0;
+                if (last_page == NULL)
+                {
+                    mm_free_page_ptr = (u32_t *) base_address;
+                }
+                else
+                {
+                    *last_page = base_address;
+                }
+                last_page = page_virtual_address;
+                mm_num_free_pages++;
+            }
+            base_address += PAGE_SIZE;
+        }
     }
 
     /* Clear the page directory */
-    for (unsigned int i = 0;
+    for (unsigned int i = 0; i < NUM_PAGETABLE_ENTRIES; i++)
-         i < sizeof(page_directory) / sizeof(page_directory[0]);
-         i++)
     {
         page_directory[i] = 0;
     }

kernel/mm/mm.h

@@ -12,8 +12,10 @@ extern "C" {
 
 typedef u32_t pagedirectory_entry_t;
 
+#define NUM_PAGETABLE_ENTRIES (PAGE_SIZE / sizeof(pagedirectory_entry_t))
+
 typedef pagedirectory_entry_t
-    pagedirectory_t[PAGE_SIZE / sizeof(pagedirectory_entry_t)];
+    pagedirectory_t[NUM_PAGETABLE_ENTRIES];
 
 extern pagedirectory_t page_directory;