emumem.cpp

這是一個arm模擬器 以C++實做 主要模擬ARM9架構

/*************************************************************************
    Copyright (C) 2002 - 2007 Wei Qin
    See file COPYING for more information.

    This program is free software; you can redistribute it and/or modify    
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*************************************************************************/

#include "emumem.h"

#include <cassert>
#include <csignal>
#include <cstring>
#include <cstdlib>

using namespace simit;

memory::memory(unsigned int def_perm, int sig)
{
	def_perm &= MEMORY_PAGE_PERM_MASK;

	/* if nonempty permission, then all pages are valid by default */
	if (def_perm) 
	{
		for (unsigned int ii=0; ii<MEMORY_PAGE_TABLE_SIZE; ii++)
			page_table[ii].flag = 
				MEMORY_PAGE_EMPTY | (def_perm << MEMORY_PAGE_PERM_SHIFT);
	}
	/* otherwise all pages are invalid by default */
	else 
	{
		for (unsigned int ii=0; ii<MEMORY_PAGE_TABLE_SIZE; ii++)
			page_table[ii].flag = MEMORY_PAGE_UNAVAIL;
	}

	page_count = 0;
	fault_sig = sig;
}

memory::~memory()
{
	for(unsigned int ii = 0; ii < MEMORY_PAGE_TABLE_SIZE; ii++)
	{
		memory_page_table_entry_t *pte = page_table + ii;
		if (page_allocated(pte)) 
			free_page(pte);
	}

}

memory::memory(const memory& mem)
{

	page_count = 0;
	fault_sig = mem.fault_sig;

	for(unsigned ii = 0; ii < MEMORY_PAGE_TABLE_SIZE; ii++)
	{
		page_table[ii].flag = mem.page_table[ii].flag;
		if (page_allocated(mem.page_table + ii))
		{
			page_table[ii].ptr = (byte_t *)malloc(MEMORY_PAGE_SIZE);
			if (page_table[ii].ptr == NULL)
			{
				report_fault(MEM_NOMEMORY_FAULT, 0);
				return;
			}

			memcpy(page_table[ii].ptr,
				mem.page_table[ii].ptr + (ii << MEMORY_PAGE_SIZE_BITS),
				MEMORY_PAGE_SIZE);
			page_table[ii].ptr -= ii << MEMORY_PAGE_SIZE_BITS;
			page_count++;
		}
	}
}

void memory::reset()
{
	for(unsigned int ii = 0; ii < MEMORY_PAGE_TABLE_SIZE; ii++)
	{
		memory_page_table_entry_t *pte = page_table + ii;
		if (page_allocated(pte)) 
		{
			free_page(pte);
		}
		else if (page_remapped(pte))
		{
			reinterpret_cast<memory_ext_interface *>(pte->ptr)->reset();
		}
	}
	page_count = 0;
}



unsigned int memory::get_page_permission(target_addr_t addr) const
{
	const memory_page_table_entry_t *pte = get_page(addr);
	unsigned int flag = pte->flag;
	if (flag & MEMORY_PAGE_SLOW)
		flag >>= MEMORY_PAGE_PERM_SHIFT;
	return (flag & MEMORY_PAGE_PERM_MASK);
}

void memory::set_page_permission(target_addr_t addr, unsigned int perm)
{
	memory_page_table_entry_t *pte = get_page(addr);

	// do nothing if the page is not available
	if (pte->flag & MEMORY_PAGE_UNAVAIL) return;

	// otherwise set permission
	perm &= MEMORY_PAGE_PERM_MASK;
	if (pte->flag & MEMORY_PAGE_SLOW) 
	{
		perm = perm << MEMORY_PAGE_PERM_SHIFT;        
		pte->flag &= ~(MEMORY_PAGE_PERM_MASK << MEMORY_PAGE_PERM_SHIFT);
		pte->flag |= perm;
	}
	else
	{
		pte->flag &= ~MEMORY_PAGE_PERM_MASK;
		pte->flag |= perm;
	}
}

void memory::set_region_permission(target_addr_t addr,
	unsigned int size, unsigned int perm)
{
	target_addr_t end_addr = /* avoid overflow */
		(addr + size) < addr ? (target_addr_t)-1 : (addr + size);

	addr = align_to_page_boundary(addr);
	while (addr < end_addr)
	{
		set_page_permission(addr, perm);
		addr += MEMORY_PAGE_SIZE;
		if (addr == 0) break;	 /* no wrap-around */
	}
}


void memory::remap_page(target_addr_t addr, 
	memory_ext_interface *mif, unsigned int perm)
{
	memory_page_table_entry_t *pte = get_page(addr);

	/* free space if the page is allocated some space */
	if (page_allocated(pte))
		free_page(pte);

	pte->flag = MEMORY_PAGE_REMAPPED; 
	pte->flag |= (perm & MEMORY_PAGE_PERM_MASK) << MEMORY_PAGE_PERM_SHIFT;
	pte->ptr = reinterpret_cast<byte_t *>(mif);
}

void memory::unmap_page(target_addr_t addr)
{
	memory_page_table_entry_t *pte = get_page(addr);
	if (pte->flag & MEMORY_PAGE_REMAPPED)
		pte->flag = MEMORY_PAGE_UNAVAIL;
}

void memory::remap_region(target_addr_t addr, unsigned int size,
	memory_ext_interface *mif, unsigned int perm)
{
	target_addr_t end_addr = /* avoid overflow */
		(addr + size) < addr ? (target_addr_t)-1 : (addr + size);

	addr = align_to_page_boundary(addr);
	while (addr < end_addr)
	{
		remap_page(addr, mif, perm);
		addr += MEMORY_PAGE_SIZE;
		if (addr == 0) break;	 /* no wrap-around */
	}
}

void memory::unmap_region(target_addr_t addr, unsigned int size)
{
	target_addr_t end_addr = /* avoid overflow */
		(addr + size) < addr ? (target_addr_t)-1 : (addr + size);

	addr = align_to_page_boundary(addr);
	while (addr < end_addr)
	{
		unmap_page(addr);
		addr += MEMORY_PAGE_SIZE;
		if (addr == 0) break;	 /* no wrap-around */
	}
}



void memory::mark_page_available(target_addr_t addr, unsigned int perm)
{
	memory_page_table_entry_t *pte = get_page(addr);
	perm &= MEMORY_PAGE_PERM_MASK;

	/* if already available, change the permission only */
	if (pte->flag & MEMORY_PAGE_UNAVAIL) 
		pte->flag = MEMORY_PAGE_EMPTY | (perm << MEMORY_PAGE_PERM_SHIFT);
	else
		set_page_permission(addr, perm);
}

void memory::mark_page_unavailable(target_addr_t addr)
{
	memory_page_table_entry_t *pte = get_page(addr);

	/* free space if the page is allocated some space */
	if (page_allocated(pte))
		free_page(pte);

	pte->flag = MEMORY_PAGE_UNAVAIL; 
}

void memory::mark_region_available(target_addr_t addr,
	unsigned int size, unsigned int perm)
{
	target_addr_t end_addr = /* avoid overflow */
		(addr + size) < addr ? (target_addr_t)-1 : (addr + size);

	addr = align_to_page_boundary(addr);
	while (addr < end_addr)
	{
		mark_page_available(addr, perm);
		addr += MEMORY_PAGE_SIZE;
		if (addr == 0) break;	 /* no wrap-around */
	}
}

void memory::mark_region_unavailable(target_addr_t addr, unsigned int size)
{
	target_addr_t end_addr = /* avoid overflow */
		(addr + size) < addr ? (target_addr_t)-1 : (addr + size);

	addr = align_to_page_boundary(addr);
	addr = align_to_page_boundary(addr);
	while (addr < end_addr)
	{
		mark_page_unavailable(addr);
		addr += MEMORY_PAGE_SIZE;
		if (addr == 0) break;	 /* no wrap-around */
	}
}



memory_fault_t memory::allocate_page(memory_page_table_entry_t *pte)
{
	assert(!page_allocated(pte));

	pte->ptr = (byte_t *)calloc(MEMORY_PAGE_SIZE, 1);
	if (pte->ptr==NULL)
		return MEM_NOMEMORY_FAULT;

	// inherit the permission bits if any
	pte->flag = (pte->flag >> MEMORY_PAGE_PERM_SHIFT) & MEMORY_PAGE_PERM_MASK;

	// subtract the starting address from the ptr so that it is easier
	// to compute the actual address, see translate() for clue
	pte->ptr -= (pte - page_table) << MEMORY_PAGE_SIZE_BITS;
	page_count++;
	return MEM_NO_FAULT;
}


void memory::free_page(memory_page_table_entry_t *pte)
{
	assert(page_allocated(pte));

	free (pte->ptr + ((pte - page_table) << MEMORY_PAGE_SIZE_BITS));
	pte->flag = MEMORY_PAGE_EMPTY | 
		((pte->flag & MEMORY_PAGE_PERM_MASK) << MEMORY_PAGE_PERM_SHIFT);

	page_count--;
}



memory_fault_t memory::read_block_within_page(void *buf, target_addr_t addr,
		unsigned int size, unsigned int *psize)
{
	memory_fault_t fault;
	memory_page_table_entry_t *pte = get_page(addr);

	*psize = 0;
	if ((fault = check_page_permission(pte, MEMORY_PAGE_READABLE)) !=
			MEM_NO_FAULT)
	{
		report_fault(fault, addr);
		return fault;
	}

	// I/O remapped space does not understand block operation
	if (pte->flag & MEMORY_PAGE_REMAPPED)
	{
		report_fault(MEM_BADADDR_FAULT, addr);
		return MEM_BADADDR_FAULT;
	}


	/* check if crossing page boundary */
	if ((addr >> MEMORY_PAGE_SIZE_BITS) !=
		((addr + size - 1) >> MEMORY_PAGE_SIZE_BITS))
		size = MEMORY_PAGE_SIZE - (addr & (MEMORY_PAGE_SIZE - 1));

	if ((pte->flag & MEMORY_PAGE_EMPTY) && (fault = allocate_page(pte)) !=
			MEM_NO_FAULT)
	{
		report_fault(fault, addr);
		return fault;
	}

	memcpy(buf, pte->ptr + addr, size);
	*psize = size;
	return MEM_NO_FAULT;
}

memory_fault_t memory::read_block(void *buf, target_addr_t addr,
		unsigned int size)
{
	memory_fault_t ft;
	unsigned int sz, len = 0;

	/* crossing the page boundary */
	while (len < size)
	{
		if ((ft = read_block_within_page(buf, addr+len, size-len, &sz)) !=
			MEM_NO_FAULT)
			return ft;

		len += sz;
		buf = reinterpret_cast<byte_t *>(buf) + sz;
	}
	return MEM_NO_FAULT;
}

memory_fault_t memory::write_block_within_page(void *buf, target_addr_t addr,
		unsigned int size, unsigned int *psize)
{
	memory_fault_t fault;
	memory_page_table_entry_t *pte = get_page(addr);

	*psize = 0;
	if ((fault = check_page_permission(pte, MEMORY_PAGE_WRITABLE)) !=
			MEM_NO_FAULT)
	{
		report_fault(fault, addr);
		return fault;
	}

	if (pte->flag & MEMORY_PAGE_REMAPPED)
	{
		report_fault(MEM_BADADDR_FAULT, addr);
		return MEM_BADADDR_FAULT;
	}

	/* check if crossing page boundary */
	if ((addr >> MEMORY_PAGE_SIZE_BITS) !=
		((addr + size - 1) >> MEMORY_PAGE_SIZE_BITS))
		size = MEMORY_PAGE_SIZE - (addr & (MEMORY_PAGE_SIZE - 1));

	if ((pte->flag & MEMORY_PAGE_EMPTY) && (fault = allocate_page(pte)) !=
			MEM_NO_FAULT)
	{
		report_fault(fault, addr);
		return fault;
	}

	memcpy(pte->ptr + addr, buf, size);
	*psize = size;
	return MEM_NO_FAULT;
}

memory_fault_t memory::write_block(void *buf, target_addr_t addr,
		unsigned int size)
{
	memory_fault_t ft;
	unsigned int sz, len = 0;

	/* crossing the page boundary */
	while (len < size)
	{
		if ((ft = write_block_within_page(buf, addr+len, size-len, &sz)) !=
			MEM_NO_FAULT)
			return ft;

		len += sz;
		buf = reinterpret_cast<byte_t *>(buf) + sz;
	}
	return MEM_NO_FAULT;
}

memory_fault_t memory::set_block_within_page(target_addr_t addr, byte_t value, 
		unsigned int size, unsigned int *psize)
{
	memory_fault_t fault;
	memory_page_table_entry_t *pte = get_page(addr);

	*psize = 0;
	if ((fault = check_page_permission(pte, MEMORY_PAGE_WRITABLE)) !=
			MEM_NO_FAULT)
	{
		report_fault(fault, addr);
		return fault;
	}

	if (pte->flag & MEMORY_PAGE_REMAPPED)
	{
		report_fault(MEM_BADADDR_FAULT, addr);
		return MEM_BADADDR_FAULT;
	}

	/* check if crossing page boundary */
	if ((addr >> MEMORY_PAGE_SIZE_BITS) !=
		((addr + size - 1) >> MEMORY_PAGE_SIZE_BITS))
		size = MEMORY_PAGE_SIZE - (addr & (MEMORY_PAGE_SIZE - 1));