From 7d7952eb5cab57587c50a9c0d8c1bc45c55c0f2c Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Mon, 31 May 2010 23:01:17 +0800
Subject: [PATCH] New kernel stack, fixing pmem alloc bug, updated to maintain
 free page positions - Misc changes in other places

---
 Kernel/arch/x86_64/include/proc.h |  3 +++
 Kernel/arch/x86_64/main.c         |  5 ++++-
 Kernel/arch/x86_64/mm_phys.c      | 19 +++++++++++++------
 Kernel/arch/x86_64/mm_virt.c      | 25 +++++++++++++++++++++----
 4 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/Kernel/arch/x86_64/include/proc.h b/Kernel/arch/x86_64/include/proc.h
index 2672ca14..cf9a4461 100644
--- a/Kernel/arch/x86_64/include/proc.h
+++ b/Kernel/arch/x86_64/include/proc.h
@@ -41,5 +41,8 @@ typedef struct sTaskState
 	Uint	RIP, RSP, RBP;
 }	tTaskState;
 
+// === CONSTANTS ===
+#define KERNEL_STACK_SIZE	0x10000	// 64 KiB
+
 #endif
 
diff --git a/Kernel/arch/x86_64/main.c b/Kernel/arch/x86_64/main.c
index 6388d1bf..f2a92298 100644
--- a/Kernel/arch/x86_64/main.c
+++ b/Kernel/arch/x86_64/main.c
@@ -59,7 +59,10 @@ void kmain(Uint MbMagic, void *MbInfoPtr)
 	// Load Virtual Filesystem
 	VFS_Init();
 	
-	*(Uint16*)(0xB8000) = 0x1F00|'G';
+	*(Uint16*)(0xB8000) = 0x1F00|'Z';
+	*(Uint16*)(0xB8002) = 0x1F00|'Z';
+	*(Uint16*)(0xB8004) = 0x1F00|'Z';
+	*(Uint16*)(0xB8006) = 0x1F00|'Z';
 	
 	// Pass on to Independent Loader
 	Log_Log("Arch", "Starting system");
diff --git a/Kernel/arch/x86_64/mm_phys.c b/Kernel/arch/x86_64/mm_phys.c
index e8d834d8..68701b28 100644
--- a/Kernel/arch/x86_64/mm_phys.c
+++ b/Kernel/arch/x86_64/mm_phys.c
@@ -3,7 +3,7 @@
  * 
  * Physical Memory Manager
  */
-#define DEBUG	0
+#define DEBUG	1
 #include <acess.h>
 #include <mboot.h>
 #include <mm_virt.h>
@@ -368,7 +368,7 @@ tPAddr MM_AllocPhysRange(int Num, int Bits)
 				LOG("nFree = %i = 0 (super) (0x%x)", nFree, addr);
 				nFree = 0;
 				addr += 1 << (6+6);
-				addr &= (1 << (6+6)) - 1;
+				addr &= ~( (1 << (6+6)) - 1 );
 				continue;
 			}
 			// Check page block (64 pages)
@@ -376,7 +376,7 @@ tPAddr MM_AllocPhysRange(int Num, int Bits)
 				LOG("nFree = %i = 0 (main) (0x%x)", nFree, addr);
 				nFree = 0;
 				addr += 1 << (12+6);
-				addr &= (1 << (12+6)) - 1;
+				addr &= ~( (1 << (12+6)) - 1 );
 				continue;
 			}
 			// Check individual page
@@ -423,8 +423,10 @@ tPAddr MM_AllocPhysRange(int Num, int Bits)
 	for( i = 0; i < Num; i++, addr++ )
 	{
 		gaMainBitmap[addr >> 6] |= 1 << (addr & 63);
-		rangeID = MM_int_GetRangeID(addr);
+		rangeID = MM_int_GetRangeID(addr << 12);
 		giPhysRangeFree[ rangeID ] --;
+		if(addr << 12 == giPhysRangeFirst[ rangeID ])
+			giPhysRangeFirst[ rangeID ] += 1;
 	}
 	ret = addr;	// Save the return address
 	
@@ -507,15 +509,20 @@ void MM_DerefPhys(tPAddr PAddr)
 	else
 		gaMainBitmap[ page >> 6 ] &= ~(1 << (page&63));
 	
-	// TODO: Update free counts
+	// Update the free counts if the page was freed
 	if( !(gaMainBitmap[ page >> 6 ] & (1 << (page&63))) )
 	{
 		 int	rangeID;
 		rangeID = MM_int_GetRangeID( PAddr );
 		giPhysRangeFree[ rangeID ] ++;
+		if( giPhysRangeFirst[rangeID] > page )
+			giPhysRangeFirst[rangeID] = page;
+		if( giPhysRangeLast[rangeID] < page )
+			giPhysRangeLast[rangeID] = page;
 	}
 	
-	if(gaMainBitmap[ page >> 6 ] == 0) {
+	// If the bitmap entry is not -1, unset the bit in the super bitmap
+	if(gaMainBitmap[ page >> 6 ] != -1 ) {
 		gaSuperBitmap[page >> 12] &= ~(1 << ((page >> 6) & 63));
 	}
 }
diff --git a/Kernel/arch/x86_64/mm_virt.c b/Kernel/arch/x86_64/mm_virt.c
index 6924b1a8..4ec08471 100644
--- a/Kernel/arch/x86_64/mm_virt.c
+++ b/Kernel/arch/x86_64/mm_virt.c
@@ -3,6 +3,7 @@
  * 
  * Virtual Memory Manager
  */
+#define DEBUG	0
 #include <acess.h>
 #include <mm_virt.h>
 #include <proc.h>
@@ -213,7 +214,7 @@ int MM_Map(tVAddr VAddr, tPAddr PAddr)
 {
 	tPAddr	tmp;
 	
-	Log("MM_Map: (VAddr=0x%x, PAddr=0x%x)", VAddr, PAddr);
+	ENTER("xVAddr xPAddr", VAddr, PAddr);
 	
 	// Check PML4
 	//Log(" MM_Map: &PAGEMAPLVL4(%x) = %x", VAddr >> 39, &PAGEMAPLVL4(VAddr >> 39));
@@ -257,8 +258,8 @@ int MM_Map(tVAddr VAddr, tPAddr PAddr)
 	PAGETABLE(VAddr >> PTAB_SHIFT) = PAddr | 3;
 	
 	INVLPG( VAddr );
-	Log("MM_Map: RETURN 1");
-	
+
+	LEAVE('i', 1);	
 	return 1;
 }
 
@@ -559,8 +560,24 @@ tVAddr MM_NewWorkerStack(void)
 	return 0;
 }
 
+/**
+ * \brief Allocate a new kernel stack
+ */
 tVAddr MM_NewKStack(void)
 {
-	Log_KernelPanic("MM", "TODO: Implement MM_NewKStack");
+	tVAddr	base = MM_KSTACK_BASE;
+	Uint	i;
+	for( ; base < MM_KSTACK_TOP; base += KERNEL_STACK_SIZE )
+	{
+		if(MM_GetPhysAddr(base) != 0)
+			continue;
+		
+		Log("MM_NewKStack: Found one at %p", base + KERNEL_STACK_SIZE);
+		for( i = 0; i < KERNEL_STACK_SIZE; i += 0x1000)
+			MM_Allocate(base+i);
+		
+		return base + KERNEL_STACK_SIZE;
+	}
+	Log_Warning("MM", "MM_NewKStack - No address space left\n");
 	return 0;
 }
-- 
2.20.1