pm2_paging.c

小型操作系统,以VC为开发环境,需要boachs调试

	RestoreEflags(ulFlags);

	return ulPageAddr;

}

/************************************************************
*************************************************************
**      Function Name:			iPm2DoPageFault
**      Author:                 x.cheng
**
**      Comment:
**			缺页异常处理
**   
**       
**
**      List of parameters:
**			ulVirtualAddr - 引发缺页的线性地址
**
**      Return value:   
**				0 - ok
**				other - error
**
**      Revisions:
**			0.01-处理很简单，如果发生缺页了，我就申请一个页
*************************************************************
*************************************************************/
int iPm2DoPageFault(unsigned long ulVirtualAddr)
{
	unsigned long ulPageFrame;
#ifdef _DEBUG__
#ifdef _DEBUG_PAGING_
	kprintf("page fault: linear address %p\n", ulVirtualAddr);
#endif
#endif
	if ( NULL == ulVirtualAddr ) {
		kprintf("NULL address is forbidden.\n");
		return (-1);
	}
	if ( NULL == (ulPageFrame = ulPm2GetOneFreePage()) ) {
		kprintf("out of memory...\n");
		return (-1);
	}
	#ifdef _DEBUG__
	#ifdef _DEBUG_PAGING_
		kprintf("%s(): free pfn= %p, for %p\n", __FUNCTION__, ulPageFrame, ulVirtualAddr);
	#endif
	#endif

	//map page with correct attributes
	if ( ulVirtualAddr < KERNEL_VIRTUAL_START ) {
		ulPm2MapPageToVirtualAddress(ulPageFrame, ulVirtualAddr, P_PRESENT | P_WRITE | P_USER);
	} else {
		ulPm2MapPageToVirtualAddress(ulPageFrame, ulVirtualAddr, P_PRESENT | P_WRITE);
	}

	//ZeroPage((void *)ulPageFrame);
	ZeroPage((void *)PHYSICAL(ulPageFrame)); 

	return 0; 
}

/************************************************************
*************************************************************
**      Function Name:			iPm2DoPageWriteProtect
**      Author:                 x.cheng
**
**      Comment:
**			页写保护异常处理
**   
**       
**
**      List of parameters:
**			ulVirtualAddr - 引发缺页的线性地址
**
**      Return value:   
**				0 - ok
**				other - error
**
**      Revisions:
**			
*************************************************************/
int iPm2DoPageWriteProtect(unsigned long ulLinearAddr)
{
	panic("\npage write protect: linear address %p", ulLinearAddr);

	return 0;
}

/************************************************************
*************************************************************
**      Function Name:			vPm2PageInit
**      Author:                 x.cheng
**
**      Comment:
**			Initial pagine memory...
**      List of parameters:
**			no
**
**      Return value:   
**          no
**
**      Revisions:
**
*************************************************************
*************************************************************/
void vPm2PageInit(unsigned long ulMemoryEnd)
{
	unsigned long ulAddress;
	unsigned char* pucBitmap;

	DmaSetupMemoryEnd( ulMemoryEnd );
#ifdef _DEBUG__
#ifdef _DEBUG_PAGING_
	kprintf("Free pageable memory in: [%x]<->[%x]\n", DMA_MEMORY_END, ulMemoryEnd+KERNEL_VIRTUAL_START);
#endif
#endif
	
	g_pucMemoryBitmapEnd = 	g_pucMemoryBitmapStart + (ulMemoryEnd >> 12);

#ifdef _DEBUG__
#ifdef _DEBUG_PAGING_
	kprintf("page vector in: [%p]<->[%p]\n", g_pucMemoryBitmapStart, g_pucMemoryBitmapEnd);
#endif
#endif
	vDbgDummy();
	pucBitmap = g_pucMemoryBitmapStart;
	while(pucBitmap<g_pucMemoryBitmapEnd) {
		*pucBitmap = PAGE_USED;
		pucBitmap++;
	}
	
	g_pucMemoryPageableStart = g_pucMemoryBitmapStart+( (DMA_MEMORY_END-KERNEL_VIRTUAL_START) >> 12 );
#ifdef _DEBUG__
#ifdef _DEBUG_PAGING_
	kprintf("pagable memory in: [%p]<->[%p], vector in [%p<->[%p]\n", VECTOR_TO_LINEAR_ADDRESS(g_pucMemoryPageableStart), VECTOR_TO_LINEAR_ADDRESS(g_pucMemoryBitmapEnd), 
											g_pucMemoryPageableStart, g_pucMemoryBitmapEnd);
#endif
#endif
	pucBitmap = g_pucMemoryPageableStart;
	while(pucBitmap<g_pucMemoryBitmapEnd) {
		*pucBitmap = 0;
		pucBitmap++;
	}

	*pulAddressToPde( 0 ) = NULL;	//unmap the first identical-map pages.
	*pulAddressToPde( 0x400000 ) = NULL;	//unmap the second identical-map pages.

	//in head.asm, we map the first 8M to 0xc0000000-0xc08000000,
	//here, we map the remainder, if we have......
	if ( ulMemoryEnd > 8*1024*1024 ) {
		for( ulAddress = 0xc0800000; ulAddress < (ulMemoryEnd+KERNEL_VIRTUAL_START); ulAddress += PAGE_SIZE )
			ulPm2MapPageToVirtualAddress( ulAddress-KERNEL_VIRTUAL_START, ulAddress, P_PRESENT | P_WRITE | P_USER );
	}
	vDbgDummy();	
#ifdef _DEBUG__
#ifdef _DEBUG_PAGING_
	kprintf("kernel text section in: [%p]<->[%p]\n", &KernelTextSectionStart_, &KernelTextSectionEnd_);
#endif
#endif
	// Initialize kernel code section in read-only mode.
	for( ulAddress = (unsigned long)&KernelTextSectionStart_; ulAddress < (unsigned long)&KernelTextSectionEnd_; ulAddress += PAGE_SIZE )
		if( *pulAddressToPde(ulAddress) )
			*pulAddressToPte( ulAddress ) &= ~P_WRITE;
/*  //等完成了系统调用再加上去！
	// Map only the exit point address available for users.
	*pulAddressToPde( (unsigned long)&_Task_Exit_Point ) |= P_USER;
	*pulAddressToPte( (unsigned long)&_Task_Exit_Point ) |= P_USER;
*/

	/********************************************
	 * 固定内存的映射工作
	 ********************************************/

	// Map part of physical memory into the kernel address space. only first 16MB
	for( ulAddress = KERNEL_PHYS_MEM_START; ulAddress < KERNEL_PHYS_MEM_END; ulAddress += PAGE_SIZE )
		ulPm2MapPageToVirtualAddress( ulAddress-KERNEL_PHYS_MEM_START, ulAddress, P_PRESENT | P_WRITE | P_NOCACHE );

	// Initialize temporary memory area.
	for( ulAddress = KERNEL_TEMP_START_ADDRESS; ulAddress < KERNEL_TEMP_END_ADDRESS; ulAddress += PAGE_SIZE )
        if( *pulAddressToPde(ulAddress) )
			*pulAddressToPde(ulAddress) = NULL;


#ifdef _DEBUG__
#ifdef _DEBUG_PAGING_
	Pm2ShowPageStatus();
#endif
#endif

	FlushTlbAll();

	vDbgDummy();
	g_stGdtr.uiLimit = GDTE_MAX_SIZE*GDT_ENTRY_SIZE-1;
	g_stGdtr.ulBase  = (unsigned long)astGDT;
	// Load info into GDTR //
	__asm__ __volatile__ ("lgdtl (%0)" : : "r"(&g_stGdtr));
	/* 在这之后不能调用显示函数，因为没有设置好显示内存*/

	UpdateSegmentRegs();
}

/************************************************************
*************************************************************
**      Function Name:			Pm2ShowPageStatus
**      Author:                 x.cheng
**
**      Comment:
**			显示页表页目录状态...
**
**      List of parameters:
**			no
**
**      Return value:   
**          no
**
**      Revisions:
**
*************************************************************
*************************************************************/
void Pm2ShowPageStatus( void )
{
	int i, j, k, iFree=0;

	unsigned long *pulPageTable;
	unsigned char* pucBitmap;

	pucBitmap = g_pucMemoryPageableStart;
	while(pucBitmap<g_pucMemoryBitmapEnd) {
		if( *pucBitmap == 0 )
			iFree++;
		pucBitmap++;
	}
	kprintf("system PDBR = %p\n", aulPageDir);
	kprintf("%d pages free ( of %d )\n", iFree, g_pucMemoryBitmapEnd-g_pucMemoryBitmapStart);
	vDbgDummy();

	/* aulPageDir defined in system.h, but referenced in k_init.asm */
	for (i=0; i<1024; i++) {
		if ( 1 & aulPageDir[i] ) {
			unsigned long ulAddress;
			ulAddress = 0xfffff000&aulPageDir[i];
			ulAddress += KERNEL_VIRTUAL_START;
			pulPageTable = (unsigned long *)ulAddress;
//			kprintf("pulPageTable= %p\n", pulPageTable);
			for (j=k=0; j<1024; j++){
				if (pulPageTable[j] & 1)
					k++;
			}
			/*打印有效页目录项和对应的页表中有效的页表项 */
			kprintf("\tPageDir[ %d] uses %d pages\n", i, k);
			vDbgDummy();
		}
	}
}