From e71a426f7cc3cd98e43ca8f529ee8e1e13395885 Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Mon, 31 May 2010 10:39:18 +0800
Subject: [PATCH] Fixed bug with physical memory allocation, update MM_Allocate
 to check mapping before allocating.

---
 Kernel/arch/x86_64/mm_phys.c | 11 ++++++-----
 Kernel/arch/x86_64/mm_virt.c | 22 +++++++++++++++++-----
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/Kernel/arch/x86_64/mm_phys.c b/Kernel/arch/x86_64/mm_phys.c
index 1e7c4c2a..77ca92e7 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>
@@ -314,7 +314,7 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
  */
 tPAddr MM_AllocPhysRange(int Num, int Bits)
 {
-	tPAddr	addr;
+	tPAddr	addr, ret;
 	 int	rangeID;
 	 int	nFree = 0, i;
 	
@@ -420,12 +420,13 @@ tPAddr MM_AllocPhysRange(int Num, int Bits)
 	
 	// Mark pages as allocated
 	addr -= Num;
-	for( i = 0; i < Num; i++ )
+	for( i = 0; i < Num; i++, addr++ )
 	{
 		gaMainBitmap[addr >> 6] |= 1 << (addr & 63);
 		rangeID = MM_int_GetRangeID(addr);
 		giPhysRangeFree[ rangeID ] --;
 	}
+	ret = addr;	// Save the return address
 	
 	// Update super bitmap
 	Num += addr & (64-1);
@@ -438,8 +439,8 @@ tPAddr MM_AllocPhysRange(int Num, int Bits)
 	}
 	
 	RELEASE(&glPhysicalPages);
-	LEAVE('x', addr << 12);
-	return addr << 12;
+	LEAVE('x', ret << 12);
+	return ret << 12;
 }
 
 /**
diff --git a/Kernel/arch/x86_64/mm_virt.c b/Kernel/arch/x86_64/mm_virt.c
index 8e5ef9c8..b4b26ec1 100644
--- a/Kernel/arch/x86_64/mm_virt.c
+++ b/Kernel/arch/x86_64/mm_virt.c
@@ -281,19 +281,31 @@ tPAddr MM_Allocate(tVAddr VAddr)
 {
 	tPAddr	ret;
 	
-	Log("MM_Allocate: (VAddr=%x)", VAddr);
-	Log("MM_Allocate: MM_AllocPhys()");
+	ENTER("xVAddr", VAddr);
+	
+	if( !MM_Map(VAddr, 0) )	// Make sure things are allocated
+	{
+		Warning("MM_Allocate: Unable to map, tables did not initialise");
+		LEAVE('i', 0);
+		return 0;
+	}
+	
 	ret = MM_AllocPhys();
-	Log("MM_Allocate: ret = %x", ret);
-	if(!ret)	return 0;
+	LOG("ret = %x", ret);
+	if(!ret) {
+		LEAVE('i', 0);
+		return 0;
+	}
 	
 	if( !MM_Map(VAddr, ret) )
 	{
-		Warning("MM_Allocate: Unable to map", ret);
+		Warning("MM_Allocate: Unable to map. Strange, we should have errored earlier");
 		MM_DerefPhys(ret);
+		LEAVE('i');
 		return 0;
 	}
 	
+	LEAVE('x', ret);
 	return ret;
 }
 
-- 
2.20.1