Add some reserved space in memory for a nonpaged pool.

Fix DEBUG_MEM #define for kmalloc/kfree.
Send memory debugging output to COM1 (for the simple debugger).
Note: This experimental branch is still broken for now.

Author: coderTrevor

MyOS_1/Build_Number.h

@@ -3,4 +3,4 @@
 // Define a build number. This number will be incremented by a simple console program called by a post-build event
 // It's put here in its own file to keep the other program from messing up the source
 #define \
-BUILD_NUMBER 6563
+BUILD_NUMBER 6605

MyOS_1/kmisc.c

@@ -1,7 +1,10 @@
 #include "paging.h"
 #include "printf.h"
+#include "Interrupts\System_Calls.h"
 #include "kmisc.h"
 #include "misc.h"
+#include "Console_Serial.h"
+#include "Tasks/Context.h"
 
 // Functions used by the kernel & drivers
 
@@ -20,10 +23,10 @@ unsigned int knextFreeMemorySlot = 0;
 
 #ifdef DEBUG_MEM
 #define noFileName "FILENAME NOT SET";
-char *dbgMemFilename = noFileName;
-int   dbgMemLineNumber = 0;
-char *dbgFreeFilename = noFileName;
-int   dbgFreeLineNumber = 0;
+char *dbgkMemFilename = noFileName;
+int   dbgkMemLineNumber = 0;
+char *dbgkFreeFilename = noFileName;
+int   dbgkFreeLineNumber = 0;
 #endif 
 
 inline void addAllocationToKFreeMemoryArray(int allocationIndex)
@@ -40,6 +43,16 @@ inline void addAllocationToKFreeMemoryArray(int allocationIndex)
     kfreeMemoryArray.inUse[knextFreeMemorySlot++] = true;
 }
 
+#ifdef DEBUG_MEM
+void *dbg_kmalloc(size_t size, char *filename, int lineNumber)
+{
+    dbgkMemFilename = filename;
+    dbgkMemLineNumber = lineNumber;
+    serial_printf("Allocating %d bytes from %s, line %d for %s\n", size, filename, lineNumber, tasks[currentTask].imageName);
+    return kmalloc(size);
+}
+#endif
+
 // Allocate some kernel memory. Mostly this is meant to be used by drivers.
 // This will be mapped into every tasks page space and will be allocated contiguously
 // TODO: Is it better to have this crazy scheme with the two functions, or just modify malloc to make sure
@@ -54,10 +67,10 @@ void* kmalloc(size_t size)
     }
 
 #ifdef DEBUG_MEM
-    kallocationArray.lineNumber[knextAllocationSlot] = dbgMemLineNumber;
-    strncpy(kallocationArray.filename[knextAllocationSlot], dbgMemFilename, MAX_DEBUG_FILENAME_LENGTH);
-    dbgMemFilename = noFileName;
-    dbgMemLineNumber = 0;
+    kallocationArray.lineNumber[knextAllocationSlot] = dbgkMemLineNumber;
+    strncpy(kallocationArray.filename[knextAllocationSlot], dbgkMemFilename, MAX_DEBUG_FILENAME_LENGTH);
+    dbgkMemFilename = noFileName;
+    dbgkMemLineNumber = 0;
 #endif
 
     // See if there's freed memory available to reallocate (first fit algorithm; memory will end up wasted)
@@ -145,6 +158,16 @@ void* kmalloc(size_t size)
     return (void *)availableAddress;
 }
 
+#ifdef DEBUG_MEM
+void dbg_kfree(void *ptr, char *filename, int lineNumber)
+{
+    dbgkFreeFilename = filename;
+    dbgkFreeLineNumber = lineNumber;
+    serial_printf("Freeing mem from %s, line %d for %s\n", filename, lineNumber, tasks[currentTask].imageName);
+    kfree(ptr);
+}
+#endif
+
 void kfree(void *ptr)
 {
     // Find this pointer in the allocation array
@@ -179,9 +202,9 @@ void kfree(void *ptr)
 
     kprintf("free() called with invalid pointer: 0x%lX", ptr);
 #ifdef DEBUG_MEM
-    printf("   from %s, line %d\n", dbgFreeFilename, dbgFreeLineNumber);
-    dbgFreeFilename = noFileName;
-    dbgFreeLineNumber = 0;
+    printf("   from %s, line %d\n", dbgkFreeFilename, dbgkFreeLineNumber);
+    dbgkFreeFilename = noFileName;
+    dbgkFreeLineNumber = 0;
     //for (;;)
     //    __halt();
 #else

MyOS_1/misc.c

@@ -7,6 +7,7 @@
 #include "Interrupts/Interrupts.h"
 #include "Console_Serial.h"
 #include <float.h>
+#include "Tasks/Context.h"
 
 uint32_t pagedMemoryAvailable = 0;
 uint32_t memoryNextAvailableAddress = 0;
@@ -64,6 +65,7 @@ void dbg_free(void *ptr, char *filename, int lineNumber)
 {
     dbgFreeFilename = filename;
     dbgFreeLineNumber = lineNumber;
+    serial_printf("Freeing mem from %s, line %d for %s\n", filename, lineNumber, tasks[currentTask].imageName);
     free(ptr);
 }
 #endif
@@ -136,6 +138,10 @@ void* realloc(void* ptr, size_t size)
 
     void *ptrNew = malloc(size);
 
+#ifdef MYOS_KERNEL
+    serial_printf("realloc called\n");
+#endif
+
     // Find ptr in allocation array
     int index;
     for (index = 0; index < MAX_ALLOCATIONS; ++index)
@@ -383,6 +389,7 @@ void *dbg_malloc(size_t size, char *filename, int lineNumber)
 {
     dbgMemFilename = filename;
     dbgMemLineNumber = lineNumber;
+    serial_printf("Allocating %d bytes from %s, line %d for %s\n", size, filename, lineNumber, tasks[currentTask].imageName);
     return malloc(size);
 }
 #endif

MyOS_1/misc.h

@@ -11,7 +11,7 @@ extern "C" {
 #include "kmisc.h"
 #endif
 
-//#define DEBUG_MEM
+#define DEBUG_MEM
 
 #ifdef DEBUG_MEM
 #define MAX_DEBUG_FILENAME_LENGTH 24

MyOS_1/paging.c

@@ -17,6 +17,7 @@ uint32_t *pageDir;
 
 uint32_t pagingNextAvailableMemory;     // physical address of the next available page
 uint32_t pagingNextAvailableKernelPage; // The index into the page directory where the next kernel page can go
+uint32_t pagingKernelNonPagedArea;      // A page (4MiB) of non-paged, identity-mapped memory drivers can use (non-paged pool)
 uint32_t paging4MPagesAvailable;        // number of 4M physical memory pages available to be mapped
 
 uint32_t nextPageDirectory; // TEMPTEMP where the next created page directory will be stored

MyOS_1/paging.h

@@ -28,6 +28,7 @@ extern uint32_t *pageDir;
 
 extern uint32_t pagingNextAvailableMemory;
 extern uint32_t pagingNextAvailableKernelPage;
+extern uint32_t pagingKernelNonPagedArea;
 extern uint32_t paging4MPagesAvailable;
 extern uint32_t nextPageDirectory; // TEMPTEMP
 
@@ -74,9 +75,12 @@ inline void Paging_Enable(multiboot_info *multibootInfo)
     // Identity map the next four megs (this is used by the GUI shell)
     pageDirectory[3] = (PAGE_DIRECTORY_ENTRY)((uint32_t)0xC00000 | DIRECTORY_ENTRY_PRESENT | DIRECTORY_ENTRY_WRITABLE | DIRECTORY_ENTRY_4MB | DIRECTORY_ENTRY_USER_ACCESSIBLE);
 
-    // Identity map the next four megs
+    // Identity map the next four megs (this is used for applications' page tables)
     pageDirectory[4] = (PAGE_DIRECTORY_ENTRY)((uint32_t)0x1000000 | DIRECTORY_ENTRY_PRESENT | DIRECTORY_ENTRY_WRITABLE | DIRECTORY_ENTRY_4MB | DIRECTORY_ENTRY_USER_ACCESSIBLE);
 
+    // Another 4 megs - this one is used by the non-paged pool (for drivers)
+    pageDirectory[5] = (PAGE_DIRECTORY_ENTRY)((uint32_t)0x1400000 | DIRECTORY_ENTRY_PRESENT | DIRECTORY_ENTRY_WRITABLE | DIRECTORY_ENTRY_4MB | DIRECTORY_ENTRY_USER_ACCESSIBLE);
+
     // Map the kernel (4 megs starting at 0x10 0000) to 0xC000 0000
     for (i = 0; i < 1024; ++i)
     {
@@ -125,20 +129,23 @@ inline void Paging_Enable(multiboot_info *multibootInfo)
     // save a pointer to pageDirectory
     pageDir = pageDirectory;
 
-    // determine available pages
-    pagingNextAvailableMemory = FOUR_MEGABYTES * 5; // TEMP: Next available page will (likely) start at 20 Megs
-    // We'll assume we have 64 megs available
-    paging4MPagesAvailable = 16; // TODO: Calculate based on the memory map Grub gave us
-
     // TEMPTEMP: put page directories between 16 - 20 megs
     nextPageDirectory = FOUR_MEGABYTES * 4;
 
+    // TEMPTEMP: put a non-paged pool of memory between 20 - 24 megs
+    pagingKernelNonPagedArea = FOUR_MEGABYTES * 5;
+
     // Walk through the mem map grub gave us
     // TODO: Assert that grub gave us a memory map
     // TODO: Don't assume we have memory at the beginning of RAM
     // TODO: Use all the entries we get from GRUB
     multiboot_mmap_entry *entry = (multiboot_mmap_entry *)multibootInfo->mmap_addr;
-    
+
+    // determine available pages
+    pagingNextAvailableMemory = FOUR_MEGABYTES * 6; // TEMP: Next available page will (likely) start at 24 Megs
+                                                    // We'll assume we have 64 megs available
+    //paging4MPagesAvailable = 16; // TODO: Calculate based on the memory map Grub gave us
+
     // examine each mmap entry
     for (uint32_t offset = 0; offset <= multibootInfo->mmap_length && entry->size; offset += entry->size + 4)
     {
@@ -150,10 +157,10 @@ inline void Paging_Enable(multiboot_info *multibootInfo)
                 // determine how many pages we really have available
                 uint64_t addrEnd = entry->addr + entry->len;
                 uint64_t bytesAvailable = addrEnd - pagingNextAvailableMemory;
-                paging4MPagesAvailable = bytesAvailable / FOUR_MEGABYTES;
+                paging4MPagesAvailable = (uint32_t)(bytesAvailable / (uint64_t)FOUR_MEGABYTES);
                 return;
             }
-        }        
+        }
 
         // advance pointer to next entry
         entry = (multiboot_mmap_entry*)((uint32_t)entry + entry->size + 4);