From: John Hodge <tpg@mutabah.net>
Date: Mon, 17 Mar 2014 05:40:15 +0000 (+0800)
Subject: Kernel/x86 - Evil hack to do validation of virtual memory
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=2b339e917d778c76b249457bcb66c4fb0007c495;p=tpg%2Facess2.git

Kernel/x86 - Evil hack to do validation of virtual memory
---

diff --git a/KernelLand/Kernel/arch/x86/validate_vmem.c b/KernelLand/Kernel/arch/x86/validate_vmem.c
new file mode 100644
index 00000000..11d504a4
--- /dev/null
+++ b/KernelLand/Kernel/arch/x86/validate_vmem.c
@@ -0,0 +1,199 @@
+/*
+ */
+#include <acess.h>
+#include <mm_virt.h>
+#include "include/vmem_layout.h"
+#include <threads_int.h>
+#include <stdbool.h>
+
+extern Uint64	giPageCount;
+extern tProcess	*gAllProcesses;
+extern char	gKernelEnd[];
+
+// === PROTOTYPES ===
+void	Validate_VirtualMemoryUsage(void);
+void	Validate_VirtualMemoryUsage_PT(const Uint32 *PTable, const tProcess *Proc, int PDIndex, int *RefCounts);
+static bool	_should_skip_pde(const tProcess *Proc, int idx, Uint32 pde);
+static void	_ref_mem(int *RefCounts, Uint PageNum, const tProcess *Proc, void *addr);
+static void	_load_page(Uint32 *dst, tPAddr phys);
+
+// === CODE ===
+void Validate_VirtualMemoryUsage(void)
+{
+	 int	*refcount = calloc(giPageCount, sizeof(int));
+	Uint32	*tmp_pd = malloc( PAGE_SIZE );
+	Uint32	*tmp_pt = malloc( PAGE_SIZE );
+	
+	// Pass #1 - Count PT references
+	for( tProcess *proc = gAllProcesses; proc; proc = proc->Next )
+	{
+		Uint	cr3 = proc->MemState.CR3;
+		_ref_mem(refcount, cr3/PAGE_SIZE, proc, 0);
+
+		_load_page(tmp_pd, cr3);
+		const Uint32	*pdir = tmp_pd;
+		for(int i = 0; i < 1024; i ++)
+		{
+			if( _should_skip_pde(proc, i, pdir[i]) )
+				continue ;
+			Uint32	ptaddr = pdir[i] & ~0xFFF;
+			
+			_ref_mem(refcount, ptaddr/PAGE_SIZE, proc, (void*)(i*1024*PAGE_SIZE));
+		}
+	}
+	
+	
+	for( tProcess *proc = gAllProcesses; proc; proc = proc->Next )
+	{
+		Uint	cr3 = proc->MemState.CR3;
+		
+		_load_page(tmp_pd, cr3);
+		const Uint32	*pdir = tmp_pd;
+		for(int i = 0; i < 1024; i ++)
+		{
+			Uint32	pde = pdir[i];
+			if( _should_skip_pde(proc, i, pde) )
+				continue ;
+			
+			Uint32	ptaddr = pde & ~0xFFF;
+			
+			// 
+			if( proc->PID == 0 || refcount[ ptaddr >> 12 ] == 1 )
+			{
+				_load_page(tmp_pt, ptaddr);
+				Validate_VirtualMemoryUsage_PT(tmp_pt, proc, i, refcount);
+			}
+		}
+	}
+	
+	for( int i = 0; i < giPageCount; i ++ )
+	{
+		 int	recorded_refc = MM_GetRefCount(i*PAGE_SIZE);
+		
+		void	*node;
+		if( MM_GetPageNode(i*PAGE_SIZE, &node) == 0 && node != NULL )
+			_ref_mem(refcount, i, NULL, 0);
+		
+		// 0x9F000 - BIOS memory area
+		// 0xA0000+ - ROM area
+		if( 0x9F <= i && i < 0x100 ) {
+			_ref_mem(refcount, i, NULL, 0);
+		}
+		
+		if( recorded_refc != refcount[i] ) {
+			Debug("Refcount mismatch %P - recorded %i != checked %i",
+				(tPAddr)i*PAGE_SIZE, recorded_refc, refcount[i]);
+		}
+	}
+	
+	// Output.
+	for( tProcess *proc = gAllProcesses; proc; proc = proc->Next )
+	{
+		Debug("%p(%i %s)", proc, proc->PID, proc->FirstThread->ThreadName);
+		Uint	cr3 = proc->MemState.CR3;
+		
+		_load_page(tmp_pd, cr3);
+		const Uint32	*pdir = tmp_pd;
+		for(int i = 0; i < 1024; i ++)
+		{
+			Uint32	pde = pdir[i];
+			if( _should_skip_pde(proc, i, pde) )
+				continue ;
+			Uint32	paddr = pde & ~0xFFF;
+			
+			if( proc->PID != 0 && refcount[ paddr >> 12 ] > 1 )
+				continue ;
+			
+			if( MM_GetRefCount(paddr) != refcount[paddr>>12] ) {
+				Debug("Table %p(%i %s) @%p %P %i!=%i",
+					proc, proc->PID, proc->FirstThread->ThreadName,
+					i*1024*PAGE_SIZE, paddr,
+					MM_GetRefCount(paddr), refcount[paddr>>12]
+					);
+			}
+	
+			_load_page(tmp_pt, paddr);
+			const Uint32 *ptab = tmp_pt;
+			for( int j = 0; j < 1024; j ++ ) 
+			{
+				if( !(ptab[j] & 1) )
+					continue ;
+				Uint32	pageaddr = ptab[j] & ~0xFFF;
+				
+				if( pageaddr/PAGE_SIZE >= giPageCount )
+				{
+					//Debug("PG %p(%i %s) @%p %P not in RAM",
+					//	proc, proc->PID, proc->FirstThread->ThreadName,
+					//	(i*1024+j)*PAGE_SIZE, pageaddr
+					//	);
+				}
+				else if( MM_GetRefCount(pageaddr) != refcount[pageaddr>>12] ) {
+					Debug("PG %p(%i %s) @%p %P %i!=%i",
+						proc, proc->PID, proc->FirstThread->ThreadName,
+						(i*1024+j)*PAGE_SIZE, pageaddr,
+						MM_GetRefCount(pageaddr), refcount[pageaddr>>12]
+						);
+				}
+			}
+		}
+	}
+}
+
+void Validate_VirtualMemoryUsage_PT(const Uint32 *PTable, const tProcess *Proc, int PDIndex, int *RefCounts)
+{
+	for( int i = 0; i < 1024; i ++ )
+	{
+		// Ignore the 3GB+1MB area
+		if( PDIndex == 768 && i < 256 )
+			continue ;
+		// And ignore anything from the end of the kernel up to 3GB4MB
+		if( PDIndex == 768 && i > ((tVAddr)gKernelEnd-KERNEL_BASE)/PAGE_SIZE )
+			continue ;
+		
+		Uint32	pte = PTable[i];
+		if( !(pte & 1) )
+			continue ;
+		
+		Uint32	paddr = pte & ~0xFFF;
+		Uint	page = paddr >> 12;
+		
+		_ref_mem(RefCounts, page, Proc, (void*)((PDIndex*1024+i)*PAGE_SIZE));
+	}
+}
+
+bool _should_skip_pde(const tProcess *Proc, int idx, Uint32 pde)
+{
+	if( !(pde & 1) )
+		return true;
+	
+	if( (pde & ~0xFFF) == Proc->MemState.CR3 ) {
+		return true;
+	}
+
+	if( idx == PAGE_TABLE_ADDR>>22 ) {
+		if( (pde & ~0xFFF) != Proc->MemState.CR3 ) {
+			// Bad!
+		}
+	}	
+	
+	return false;
+}
+
+void _ref_mem(int *RefCounts, Uint PageNum, const tProcess *Proc, void *addr)
+{
+	if( PageNum == 0x1001000/PAGE_SIZE ) {
+		Debug("frame #0x%x %i:%p", PageNum, Proc?Proc->PID:-1, addr);
+	}
+	if( PageNum >= giPageCount )
+		;
+	else
+		RefCounts[ PageNum ] ++;
+}
+
+void _load_page(Uint32 *dst, tPAddr phys)
+{
+	const void *src = MM_MapTemp(phys);
+	memcpy(dst, src, PAGE_SIZE);
+	MM_FreeTemp( (void*)src);
+}
+