module.c

/*
 * File      : module.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2010-01-09     Bernard      first version
 * 2010-04-09     yi.qiu       implement based on first version
 * 2010-10-23     yi.qiu       implement module memory allocator
 * 2011-05-25     yi.qiu       implement module hook function
 * 2011-06-23     yi.qiu       rewrite module memory allocator
 */

#include <rthw.h>
#include <rtthread.h>
#include <rtm.h>

#include "string.h"

#ifdef RT_USING_MODULE
#include "module.h"

#define elf_module          ((Elf32_Ehdr *)module_ptr)
#define shdr                ((Elf32_Shdr *)((rt_uint8_t *)module_ptr + elf_module->e_shoff))
#define phdr                ((Elf32_Phdr *)((rt_uint8_t *)module_ptr + elf_module->e_phoff))

#define IS_PROG(s)          (s.sh_type == SHT_PROGBITS)
#define IS_NOPROG(s)        (s.sh_type == SHT_NOBITS)
#define IS_REL(s)           (s.sh_type == SHT_REL)
#define IS_RELA(s)          (s.sh_type == SHT_RELA)
#define IS_ALLOC(s)         (s.sh_flags == SHF_ALLOC)
#define IS_AX(s)            ((s.sh_flags & SHF_ALLOC) && (s.sh_flags & SHF_EXECINSTR))
#define IS_AW(s)            ((s.sh_flags & SHF_ALLOC) && (s.sh_flags & SHF_WRITE))

#define PAGE_COUNT_MAX	256

/* module memory allocator */
struct rt_mem_head
{
	rt_size_t size;				/* size of memory block  */
	struct rt_mem_head *next;		/* next valid memory block */
};

struct rt_page_info
{
	rt_uint32_t *page_ptr;
	rt_uint32_t npage;
};

#ifdef RT_USING_SLAB
static void *rt_module_malloc_page(rt_size_t npages);
static void rt_module_free_page(rt_module_t module, void *page_ptr, rt_size_t npages);
#endif

static rt_module_t rt_current_module = RT_NULL;
static struct rt_semaphore mod_sem;
static struct rt_module_symtab *_rt_module_symtab_begin = RT_NULL, *_rt_module_symtab_end = RT_NULL;
rt_list_t rt_module_symbol_list;

static char *_strip_name(const char *string)
{
	int i = 0, p = 0, q = 0;
	const char *str = string;
	char *dest = RT_NULL;

	while (*str != '\n' && *str != '\0')
	{
		if (*str =='/' ) p = i + 1;
		if (*str == '.') q = i;
		str++; i++;
	}

	if (p < q)
	{
		int len = q - p;
		dest = (char *)rt_malloc(len + 1);
		rt_strncpy(dest, &string[p], len);
		dest[len] = '\0';
	}

	return dest;
}

/**
 * @ingroup SystemInit
 *
 * This function will initialize system module
 */
void rt_system_module_init(void)
{
#ifdef __GNUC__
	extern int __rtmsymtab_start;
	extern int __rtmsymtab_end;
	
	_rt_module_symtab_begin = (struct rt_module_symtab *)&__rtmsymtab_start;
	_rt_module_symtab_end   = (struct rt_module_symtab *)&__rtmsymtab_end;
#elif defined (__CC_ARM)
	extern int RTMSymTab$$Base;
	extern int RTMSymTab$$Limit;

	_rt_module_symtab_begin = (struct rt_module_symtab *)&RTMSymTab$$Base;
	_rt_module_symtab_end   = (struct rt_module_symtab *)&RTMSymTab$$Limit;	
#endif

	rt_list_init(&rt_module_symbol_list);

	/* initialize heap semaphore */
	rt_sem_init(&mod_sem, "module", 1, RT_IPC_FLAG_FIFO);

	/* init current module */
	rt_current_module = RT_NULL;
}

static rt_uint32_t rt_module_symbol_find(const char *sym_str)
{
	/* find in kernel symbol table */
	struct rt_module_symtab *index;
	for (index = _rt_module_symtab_begin; index != _rt_module_symtab_end; index ++)
	{
		if (rt_strcmp(index->name, sym_str) == 0)
			return (rt_uint32_t)index->addr;
	}

	return 0;
}

/**
 * This function will return self module object
 *
 * @return the self module object
 */
rt_module_t rt_module_self(void)
{
	/* return current module */
	return rt_current_module;
}

/**
 * This function will set current module object
 *
 * @return RT_EOK
 */
rt_err_t rt_module_set(rt_module_t module)
{
	/* set current module */
	rt_current_module = module;

	return RT_EOK;
}

static int rt_module_arm_relocate(struct rt_module *module, Elf32_Rel *rel, Elf32_Addr sym_val)
{
	Elf32_Addr *where, tmp;
	Elf32_Sword addend, offset;
	rt_uint32_t upper, lower, sign, j1, j2;

	where = (Elf32_Addr *)((rt_uint8_t *)module->module_space + rel->r_offset);
	switch (ELF32_R_TYPE(rel->r_info))
	{
	case R_ARM_NONE:
		break;
	case R_ARM_ABS32:
		*where += (Elf32_Addr)sym_val;
		RT_DEBUG_LOG(RT_DEBUG_MODULE, ("R_ARM_ABS32: %x -> %x\n", where, *where));
		break;
	case R_ARM_PC24:
	case R_ARM_PLT32:
	case R_ARM_CALL:
	case R_ARM_JUMP24:
		addend = *where & 0x00ffffff;
		if (addend & 0x00800000)
			addend |= 0xff000000;
		tmp = sym_val - (Elf32_Addr)where + (addend << 2);
		tmp >>= 2;
		*where = (*where & 0xff000000) | (tmp & 0x00ffffff);
		RT_DEBUG_LOG(RT_DEBUG_MODULE, ("R_ARM_PC24: %x -> %x\n", where, *where));
		break;
	case R_ARM_REL32:
		*where += sym_val - (Elf32_Addr)where;
		RT_DEBUG_LOG(RT_DEBUG_MODULE,("R_ARM_REL32: %x -> %x, sym %x, offset %x\n", where, *where, sym_val, rel->r_offset));
		break;
	case R_ARM_V4BX:
		*where &= 0xf000000f;
		*where |= 0x01a0f000;
		break;
	case R_ARM_GLOB_DAT:
	case R_ARM_JUMP_SLOT:
		*where = (Elf32_Addr)sym_val;
		RT_DEBUG_LOG(RT_DEBUG_MODULE,
			("R_ARM_JUMP_SLOT: 0x%x -> 0x%x 0x%x\n", where, *where, sym_val));
		break;
#if 0		/* To do */
	case R_ARM_GOT_BREL:
		temp = (Elf32_Addr)sym_val;
		*where = (Elf32_Addr)&temp;
		RT_DEBUG_LOG(RT_DEBUG_MODULE,
			("R_ARM_GOT_BREL: 0x%x -> 0x%x 0x%x\n", where, *where, sym_val));
		break;
#endif
	case R_ARM_RELATIVE:
		*where += (Elf32_Addr)sym_val;
		//RT_DEBUG_LOG(RT_DEBUG_MODULE,
			//("R_ARM_RELATIVE: 0x%x -> 0x%x 0x%x\n", where, *where, sym_val));
		break;
	case R_ARM_THM_CALL:
	case R_ARM_THM_JUMP24:
		upper = *(rt_uint16_t *)where;
		lower = *(rt_uint16_t *)((Elf32_Addr)where + 2);

		sign = (upper >> 10) & 1;
		j1 = (lower >> 13) & 1;
		j2 = (lower >> 11) & 1;
		offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
			 				 ((~(j2 ^ sign) & 1) << 22) |
			 				 ((upper & 0x03ff) << 12) |
			 				 ((lower & 0x07ff) << 1);
		if (offset & 0x01000000)
			 				 offset -= 0x02000000;
		offset += sym_val - (Elf32_Addr)where;

		if (!(offset & 1) || offset <= (rt_int32_t)0xff000000 ||
			 	offset >= (rt_int32_t)0x01000000)
		{
			rt_kprintf("only Thumb addresses allowed\n");
			
			return -1;
		}

		sign = (offset >> 24) & 1;
		j1 = sign ^ (~(offset >> 23) & 1);
		j2 = sign ^ (~(offset >> 22) & 1);
		*(rt_uint16_t *)where = (rt_uint16_t)((upper & 0xf800) | (sign << 10) |
			 						 ((offset >> 12) & 0x03ff));
		*(rt_uint16_t *)(where + 2) = (rt_uint16_t)((lower & 0xd000) |
			 						   (j1 << 13) | (j2 << 11) |
			 						   ((offset >> 1) & 0x07ff));
		upper = *(rt_uint16_t *)where;
		lower = *(rt_uint16_t *)((Elf32_Addr)where + 2);
		break;
	default:
		return -1;
	}

	return 0;
}

static void rt_module_init_object_container(struct rt_module *module)
{
	RT_ASSERT(module != RT_NULL);

	/* initialize object container - thread */
	rt_list_init(&(module->module_object[RT_Object_Class_Thread].object_list));
	module->module_object[RT_Object_Class_Thread].object_size = sizeof(struct rt_thread);
	module->module_object[RT_Object_Class_Thread].type = RT_Object_Class_Thread;

#ifdef RT_USING_SEMAPHORE
	/* initialize object container - semaphore */
	rt_list_init(&(module->module_object[RT_Object_Class_Semaphore].object_list));
	module->module_object[RT_Object_Class_Semaphore].object_size = sizeof(struct rt_semaphore);
	module->module_object[RT_Object_Class_Semaphore].type = RT_Object_Class_Semaphore;
#endif

#ifdef RT_USING_MUTEX
	/* initialize object container - mutex */
	rt_list_init(&(module->module_object[RT_Object_Class_Mutex].object_list));
	module->module_object[RT_Object_Class_Mutex].object_size = sizeof(struct rt_mutex);
	module->module_object[RT_Object_Class_Mutex].type = RT_Object_Class_Mutex;
#endif

#ifdef RT_USING_EVENT
	/* initialize object container - event */
	rt_list_init(&(module->module_object[RT_Object_Class_Event].object_list));
	module->module_object[RT_Object_Class_Event].object_size = sizeof(struct rt_event);
	module->module_object[RT_Object_Class_Event].type = RT_Object_Class_Event;
#endif

#ifdef RT_USING_MAILBOX
	/* initialize object container - mailbox */
	rt_list_init(&(module->module_object[RT_Object_Class_MailBox].object_list));
	module->module_object[RT_Object_Class_MailBox].object_size = sizeof(struct rt_mailbox);
	module->module_object[RT_Object_Class_MailBox].type = RT_Object_Class_MailBox;
#endif

#ifdef RT_USING_MESSAGEQUEUE
	/* initialize object container - message queue */
	rt_list_init(&(module->module_object[RT_Object_Class_MessageQueue].object_list));
	module->module_object[RT_Object_Class_MessageQueue].object_size = sizeof(struct rt_messagequeue);
	module->module_object[RT_Object_Class_MessageQueue].type = RT_Object_Class_MessageQueue;
#endif

#ifdef RT_USING_MEMPOOL
	/* initialize object container - memory pool */
	rt_list_init(&(module->module_object[RT_Object_Class_MemPool].object_list));
	module->module_object[RT_Object_Class_MemPool].object_size = sizeof(struct rt_mempool);
	module->module_object[RT_Object_Class_MemPool].type = RT_Object_Class_MemPool;
#endif

#ifdef RT_USING_DEVICE
	/* initialize object container - device */
	rt_list_init(&(module->module_object[RT_Object_Class_Device].object_list));
	module->module_object[RT_Object_Class_Device].object_size = sizeof(struct rt_device);
	module->module_object[RT_Object_Class_Device].type = RT_Object_Class_Device;
#endif

	/* initialize object container - timer */
	rt_list_init(&(module->module_object[RT_Object_Class_Timer].object_list));
	module->module_object[RT_Object_Class_Timer].object_size = sizeof(struct rt_timer);
	module->module_object[RT_Object_Class_Timer].type = RT_Object_Class_Timer;
}

#ifdef RT_USING_HOOK
static void (*rt_module_load_hook)(rt_module_t module);
static void (*rt_module_unload_hook)(rt_module_t module);

/**
 * @addtogroup Hook
 */

/*@{*/

/**
 * This function will set a hook function, which will be invoked when module
 * be loaded to system.
 *
 * @param hook the hook function
 */
void rt_module_load_sethook(void (*hook)(rt_module_t module))
{
	rt_module_load_hook = hook;
}

/**
 * This function will set a hook function, which will be invoked when module
 * be unloaded from system.
 *
 * @param hook the hook function
 */
void rt_module_unload_sethook(void (*hook)(rt_module_t module))
{
	rt_module_unload_hook = hook;
}

/*@}*/
#endif

static struct rt_module* _load_shared_object(const char *name, void *module_ptr)
{
	rt_uint8_t *ptr = RT_NULL;
	rt_module_t module = RT_NULL;
	rt_bool_t linked = RT_FALSE;
	rt_uint32_t index, module_size = 0;

	RT_ASSERT(module_ptr != RT_NULL);

	if(rt_memcmp(elf_module->e_ident, RTMMAG, SELFMAG) == 0)
	{
		/* rtmlinker finished */
		linked = RT_TRUE;
	}
	
	/* get the ELF image size */
	for (index = 0; index < elf_module->e_phnum; index++)
	{
		if(phdr[index].p_type == PT_LOAD)
			module_size += phdr[index].p_memsz;
	}	
	
	if (module_size == 0)
	{
		rt_kprintf(" module size error\n");
		return RT_NULL;
	}	

	/* allocate module */
	module = (struct rt_module *)rt_object_allocate(RT_Object_Class_Module, name);
	if (!module) return RT_NULL;

	module->nref = 0;
	
	/* allocate module space */
	module->module_space = rt_malloc(module_size);
	if (module->module_space == RT_NULL)
	{
		rt_object_delete(&(module->parent));

		return RT_NULL;
	}

	/* zero all space */
	ptr = module->module_space;
	rt_memset(ptr, 0, module_size);

	rt_kprintf(" load address at 0x%x\n", ptr);

	for (index = 0; index < elf_module->e_phnum; index++)
	{
		if (phdr[index].p_type == PT_LOAD)
		{
			rt_memcpy(ptr, (rt_uint8_t *)elf_module + phdr[index].p_offset, phdr[index].p_filesz);
			ptr += phdr[index].p_memsz;
		}		
	}	

	/* set module entry */
	module->module_entry = module->module_space + elf_module->e_entry;
	
	/* handle relocation section */
	for (index = 0; index < elf_module->e_shnum; index ++)
	{
		if (IS_REL(shdr[index]))
		{
			rt_uint32_t i, nr_reloc;
			Elf32_Sym *symtab;
			Elf32_Rel *rel;
			rt_uint8_t *strtab;
			static rt_bool_t unsolved = RT_FALSE;

			/* get relocate item */
			rel = (Elf32_Rel *)((rt_uint8_t *)module_ptr + shdr[index].sh_offset);

			/* locate .rel.plt and .rel.dyn section */
			symtab =(Elf32_Sym *) ((rt_uint8_t*)module_ptr + shdr[shdr[index].sh_link].sh_offset);
			strtab = (rt_uint8_t*) module_ptr + shdr[shdr[shdr[index].sh_link].sh_link].sh_offset;
			nr_reloc = (rt_uint32_t) (shdr[index].sh_size / sizeof(Elf32_Rel));

			/* relocate every items */
			for (i = 0; i < nr_reloc; i ++)
			{
				Elf32_Sym *sym = &symtab[ELF32_R_SYM(rel->r_info)];

				RT_DEBUG_LOG(RT_DEBUG_MODULE,
					("relocate symbol %s shndx %d\n", strtab + sym->st_name, sym->st_shndx));

				if((sym->st_shndx != SHT_NULL) || (ELF_ST_BIND(sym->st_info) == STB_LOCAL))
					rt_module_arm_relocate(module, rel,  (Elf32_Addr)(module->module_space + sym->st_value));
				else if(!linked)
				{
					Elf32_Addr addr;

					RT_DEBUG_LOG(RT_DEBUG_MODULE,
						("relocate symbol: %s\n", strtab + sym->st_name));

					/* need to resolve symbol in kernel symbol table */
					addr = rt_module_symbol_find((const char *)(strtab + sym->st_name));
					if (addr == 0)
					{
						rt_kprintf("can't find %s in kernel symbol table\n", strtab + sym->st_name);
						unsolved = RT_TRUE;
					}	
					else
						rt_module_arm_relocate(module, rel, addr);
				}
				rel ++;
			}

			if (unsolved)
			{
				rt_object_delete(&(module->parent));
				rt_free(module);

				return RT_NULL;
			}	
		}
	}

	/* construct module symbol table */
	for (index = 0; index < elf_module->e_shnum; index ++)
	{	
		/* find .dynsym section */
		rt_uint8_t *shstrab = (rt_uint8_t *)module_ptr + shdr[elf_module->e_shstrndx].sh_offset;
		if (rt_strcmp((const char *)(shstrab + shdr[index].sh_name), ELF_DYNSYM) == 0)
			break;
	}

	/* found .dynsym section */
	if (index != elf_module->e_shnum)
	{
		int i, count = 0;
		Elf32_Sym *symtab = RT_NULL;
		rt_uint8_t *strtab = RT_NULL;

		symtab =(Elf32_Sym *)((rt_uint8_t *)module_ptr + shdr[index].sh_offset);
		strtab = (rt_uint8_t *)module_ptr + shdr[shdr[index].sh_link].sh_offset;

		for (i=0; i<shdr[index].sh_size/sizeof(Elf32_Sym); i++)
		{
			if ((ELF_ST_BIND(symtab[i].st_info) == STB_GLOBAL) && (ELF_ST_TYPE(symtab[i].st_info) == STT_FUNC))
				count ++;
		}

		module->symtab = (struct rt_module_symtab *)rt_malloc(count * sizeof(struct rt_module_symtab));
		module->nsym = count;
		for (i=0, count=0; i<shdr[index].sh_size/sizeof(Elf32_Sym); i++)
		{
			if ((ELF_ST_BIND(symtab[i].st_info) == STB_GLOBAL) && (ELF_ST_TYPE(symtab[i].st_info) == STT_FUNC))
			{
				rt_size_t length = rt_strlen((const char *)(strtab + symtab[i].st_name)) + 1;

				module->symtab[count].addr = (void *)(module->module_space + symtab[i].st_value);
				module->symtab[count].name = rt_malloc(length);
				rt_memset((void *)module->symtab[count].name, 0, length);
				rt_memcpy((void *)module->symtab[count].name, strtab + symtab[i].st_name, length);
				count ++;
			}	
		}	
	}

	return module;
}

static struct rt_module* _load_relocated_object(const char *name, void *module_ptr)
{
	rt_uint32_t index, rodata_addr = 0, bss_addr = 0, data_addr = 0;
	rt_uint32_t module_addr = 0, module_size = 0;
	struct rt_module *module = RT_NULL;
	rt_uint8_t *ptr, *strtab, *shstrab;
	rt_bool_t linked = RT_FALSE;

	if(rt_memcmp(elf_module->e_ident, RTMMAG, SELFMAG) == 0)
	{
		/* rtmlinker finished */
		linked = RT_TRUE;
	}

	/* get the ELF image size */
	for (index = 0; index < elf_module->e_shnum; index++)
	{
		/* text */
		if (IS_PROG(shdr[index]) && IS_AX(shdr[index]))
		{
			module_size += shdr[index].sh_size;
			module_addr = shdr[index].sh_addr;
		}
		/* rodata */
		if (IS_PROG(shdr[index]) && IS_ALLOC(shdr[index]))
		{
			module_size += shdr[index].sh_size;
		}
		/* data */
		if (IS_PROG(shdr[index]) && IS_AW(shdr[index]))
		{
			module_size += shdr[index].sh_size;
		}
		/* bss */
		if (IS_NOPROG(shdr[index]) && IS_AW(shdr[index]))
		{
			module_size += shdr[index].sh_size;
		}
	}

	/* no text, data and bss on image */
	if (module_size == 0)
		return RT_NULL;

	/* allocate module */
	module = (struct rt_module *)rt_object_allocate(RT_Object_Class_Module, (const char *)name);
	if (module == RT_NULL)
		return RT_NULL;

	/* allocate module space */
	module->module_space = rt_malloc(module_size);
	if (module->module_space == RT_NULL)
	{
		rt_object_delete(&(module->parent));

		return RT_NULL;
	}

	/* zero all space */
	ptr = module->module_space;
	rt_memset(ptr, 0, module_size);

	/* load text and data section */
	for (index = 0; index < elf_module->e_shnum; index++)
	{
		/* load text section */
		if (IS_PROG(shdr[index]) && IS_AX(shdr[index]))
		{
			rt_memcpy(ptr, (rt_uint8_t*)elf_module + shdr[index].sh_offset, shdr[index].sh_size);
			RT_DEBUG_LOG(RT_DEBUG_MODULE,("load text 0x%x, size %d\n", ptr, shdr[index].sh_size));
			ptr += shdr[index].sh_size;
		}

		/* load rodata section */
		if (IS_PROG(shdr[index]) && IS_ALLOC(shdr[index]))
		{
			rt_memcpy(ptr, (rt_uint8_t*)elf_module + shdr[index].sh_offset, shdr[index].sh_size);
			rodata_addr = (rt_uint32_t)ptr;
			RT_DEBUG_LOG(RT_DEBUG_MODULE,("load rodata 0x%x, size %d, rodata 0x%x\n", ptr, shdr[index].sh_size, *(rt_uint32_t*)data_addr));
			ptr += shdr[index].sh_size;
		}

		/* load data section */
		if (IS_PROG(shdr[index]) && IS_AW(shdr[index]))
		{
			rt_memcpy(ptr, (rt_uint8_t*)elf_module + shdr[index].sh_offset, shdr[index].sh_size);
			data_addr = (rt_uint32_t)ptr;
			RT_DEBUG_LOG(RT_DEBUG_MODULE,("load data 0x%x, size %d, data 0x%x\n", ptr, shdr[index].sh_size, *(rt_uint32_t*)data_addr));
			ptr += shdr[index].sh_size;
		}

		/* load bss section */
		if (IS_NOPROG(shdr[index]) && IS_AW(shdr[index]))
		{
			rt_memset(ptr, 0, shdr[index].sh_size);
			bss_addr = (rt_uint32_t)ptr;
			RT_DEBUG_LOG(RT_DEBUG_MODULE,("load bss 0x%x, size %d,\n", ptr, shdr[index].sh_size));
		}
	}

	/* set module entry */
	module->module_entry = (rt_uint8_t*)module->module_space + elf_module->e_entry - module_addr;

	/* handle relocation section */
	for (index = 0; index < elf_module->e_shnum; index ++)
	{
		if (IS_REL(shdr[index]))
		{
			rt_uint32_t i, nr_reloc;
			Elf32_Sym *symtab;
			Elf32_Rel *rel;

			/* get relocate item */
			rel = (Elf32_Rel *) ((rt_uint8_t*)module_ptr + shdr[index].sh_offset);

			/* locate .dynsym and .dynstr */
			symtab =(Elf32_Sym *) ((rt_uint8_t*)module_ptr + shdr[shdr[index].sh_link].sh_offset);
			strtab = (rt_uint8_t*) module_ptr + shdr[shdr[shdr[index].sh_link].sh_link].sh_offset;
			shstrab = (rt_uint8_t*) module_ptr + shdr[elf_module->e_shstrndx].sh_offset;
			nr_reloc = (rt_uint32_t) (shdr[index].sh_size / sizeof(Elf32_Rel));

			/* relocate every items */
			for (i = 0; i < nr_reloc; i ++)
			{
				Elf32_Sym *sym = &symtab[ELF32_R_SYM(rel->r_info)];
				RT_DEBUG_LOG(RT_DEBUG_MODULE,("relocate symbol: %s\n", strtab + sym->st_name));

				if (sym->st_shndx != STN_UNDEF)
				{
					if((ELF_ST_TYPE(sym->st_info) == STT_SECTION)
						|| (ELF_ST_TYPE(sym->st_info) == STT_OBJECT))
					{
						if (rt_strncmp(shstrab + shdr[sym->st_shndx].sh_name, ELF_RODATA, 8) == 0)
						{
							/* relocate rodata section */
							RT_DEBUG_LOG(RT_DEBUG_MODULE,("rodata\n"));
							rt_module_arm_relocate(module, rel,(Elf32_Addr)(rodata_addr + sym->st_value));
						}
						else if(rt_strncmp(shstrab + shdr[sym->st_shndx].sh_name, ELF_BSS, 5) == 0)
						{
							/* relocate bss section */
							RT_DEBUG_LOG(RT_DEBUG_MODULE,("bss\n"));
							rt_module_arm_relocate(module, rel, (Elf32_Addr)bss_addr + sym->st_value);
						}
						else if(rt_strncmp(shstrab + shdr[sym->st_shndx].sh_name, ELF_DATA, 6) == 0)
						{
							/* relocate data section */
							RT_DEBUG_LOG(RT_DEBUG_MODULE,("data\n"));
							rt_module_arm_relocate(module, rel, (Elf32_Addr)data_addr + sym->st_value);
						}
					}
				}
				else if(ELF_ST_TYPE(sym->st_info) == STT_FUNC )
				{
					/* relocate function */
					rt_module_arm_relocate(module, rel,
						(Elf32_Addr)((rt_uint8_t*)module->module_space - module_addr + sym->st_value));
				}
				else
				{
					Elf32_Addr addr;

					if(ELF32_R_TYPE(rel->r_info) != R_ARM_V4BX)
					{
						RT_DEBUG_LOG(RT_DEBUG_MODULE,("relocate symbol: %s\n", strtab + sym->st_name));
						/* need to resolve symbol in kernel symbol table */
						addr = rt_module_symbol_find(strtab + sym->st_name);
						if (addr != (Elf32_Addr)RT_NULL)
						{
							rt_module_arm_relocate(module, rel, addr);
							RT_DEBUG_LOG(RT_DEBUG_MODULE,("symbol addr 0x%x\n", addr));
						}
						else
							rt_kprintf("can't find %s in kernel symbol table\n", strtab + sym->st_name);
					}
					else
					{
						rt_module_arm_relocate(module, rel,
							(Elf32_Addr)((rt_uint8_t*)module->module_space - module_addr + sym->st_value));
					}
				}
				rel ++;
			}
		}
	}

	return module;
}

/**
 * This function will load a module from memory and create a thread for it
 *
 * @param name the name of module, which shall be unique
 * @param module_ptr the memory address of module image
 *
 * @return the module object
 */
rt_module_t rt_module_load(const char *name, void *module_ptr)
{
	rt_module_t module;

	RT_DEBUG_NOT_IN_INTERRUPT;

	rt_kprintf("rt_module_load: %s ,", name);

	/* check ELF header */
	if(rt_memcmp(elf_module->e_ident, RTMMAG, SELFMAG) != 0
		&& rt_memcmp(elf_module->e_ident, ELFMAG, SELFMAG) != 0)
	{
		rt_kprintf(" module magic error\n");

		return RT_NULL;
	}

	/* check ELF class */
	if(elf_module->e_ident[EI_CLASS] != ELFCLASS32)
	{
		rt_kprintf(" module class error\n");

		return RT_NULL;
	}

	if(elf_module->e_type == ET_REL)
	{
		module = _load_relocated_object(name, module_ptr);
	}
	else if(elf_module->e_type == ET_DYN)
	{
		module = _load_shared_object(name, module_ptr);
	}
	else
	{
		rt_kprintf("unsupported elf type\n");

		return RT_NULL;
	}

	if(module == RT_NULL)
		return RT_NULL;

	/* init module object container */
	rt_module_init_object_container(module);
		
	/* increase module reference count */
	module->nref ++;

	if (elf_module->e_entry != 0)
	{	
#ifdef RT_USING_SLAB
		/* init module memory allocator */
		module->mem_list = RT_NULL;

		/* create page array */
		module->page_array = (void *)rt_malloc(PAGE_COUNT_MAX * sizeof(struct rt_page_info));
		module->page_cnt = 0;
#endif

		/* create module thread */
		module->stack_size = 2048;
		module->thread_priority = 25;
		module->module_thread = rt_thread_create(name,
			module->module_entry, RT_NULL,
			module->stack_size,
			module->thread_priority, 10);
		
		module->module_thread->module_id = (void*)module;
		module->parent.flag = RT_MODULE_FLAG_WITHENTRY;

		/* startup module thread */
		rt_thread_startup(module->module_thread);
	}	
	else
	{
		/* without entry point */
		module->parent.flag |= RT_MODULE_FLAG_WITHOUTENTRY;
	}	

#ifdef RT_USING_HOOK
	if (rt_module_load_hook != RT_NULL)
	{
		rt_module_load_hook(module);
	}
#endif

	return module;
}	

#ifdef RT_USING_DFS
#include <dfs_posix.h>
/**
 * This function will load a module from a file
 *
 * @param path the full path of application module
 *
 * @return the module object
 */
rt_module_t rt_module_open(const char *path)
{
	int fd, length;
	struct rt_module *module;
	struct stat s;
	char *buffer, *offset_ptr;

	RT_DEBUG_NOT_IN_INTERRUPT;

	/* check parameters */
	RT_ASSERT(path != RT_NULL);

	if (stat(path, &s) !=0)
	{
		rt_kprintf("access %s failed\n", path);

		return RT_NULL;
	}
	buffer = (char *)rt_malloc(s.st_size);
	if (buffer == RT_NULL)
	{
		rt_kprintf("out of memory\n");

		return RT_NULL;
	}

	offset_ptr = buffer;
	fd = open(path, O_RDONLY, 0);
	if (fd < 0)
	{
		rt_kprintf("open %s failed\n", path);
		rt_free(buffer);

		return RT_NULL;
	}

	do
	{
		length = read(fd, offset_ptr, 4096);
		if (length > 0)
		{
			offset_ptr += length;
		}
	}while (length > 0);

	/* close fd */
	close(fd);

	if ((rt_uint32_t)offset_ptr - (rt_uint32_t)buffer != s.st_size)
	{
		rt_kprintf("check: read file failed\n");
		rt_free(buffer);

		return RT_NULL;
	}

	module = rt_module_load(path, (void *)buffer);
	rt_free(buffer);

	return module;
}

#if defined(RT_USING_FINSH)
#include <finsh.h>
FINSH_FUNCTION_EXPORT_ALIAS(rt_module_open, exec, exec module from file);
#endif
#endif

/**
 * This function will unload a module from memory and release resources
 *
 * @param module the module to be unloaded
 *
 * @return the operation status, RT_EOK on OK; -RT_ERROR on error
 */
rt_err_t rt_module_unload(rt_module_t module)
{
	int i;
	struct rt_object *object;
	struct rt_list_node *list;

	RT_DEBUG_NOT_IN_INTERRUPT;

	/* check parameter */
	RT_ASSERT(module != RT_NULL);

	rt_kprintf("rt_module_unload: %s\n", module->parent.name);

	/* module has entry point */
	if (!(module->parent.flag & RT_MODULE_FLAG_WITHOUTENTRY))
	{
		/* suspend module main thread */
		if (module->module_thread != RT_NULL)
		{
			if (module->module_thread->stat == RT_THREAD_READY)
				rt_thread_suspend(module->module_thread);
		}
		
		/* delete threads */
		list = &module->module_object[RT_Object_Class_Thread].object_list;
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_thread_detach((rt_thread_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_thread_delete((rt_thread_t)object);
			}
		}
		
#ifdef RT_USING_SEMAPHORE
		/* delete semaphores */
		list = &module->module_object[RT_Object_Class_Thread].object_list;	
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_sem_detach((rt_sem_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_sem_delete((rt_sem_t)object);
			}
		}
#endif

#ifdef RT_USING_MUTEX
		/* delete mutexs*/
		list = &module->module_object[RT_Object_Class_Mutex].object_list;	
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_mutex_detach((rt_mutex_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_mutex_delete((rt_mutex_t)object);
			}
		}
#endif

#ifdef RT_USING_EVENT
		/* delete mailboxs */
		list = &module->module_object[RT_Object_Class_Event].object_list;	
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_event_detach((rt_event_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_event_delete((rt_event_t)object);
			}
		}
#endif

#ifdef RT_USING_MAILBOX
		/* delete mailboxs */
		list = &module->module_object[RT_Object_Class_MailBox].object_list;	
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_mb_detach((rt_mailbox_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_mb_delete((rt_mailbox_t)object);
			}
		}
#endif

#ifdef RT_USING_MESSAGEQUEUE
		/* delete msgqueues */
		list = &module->module_object[RT_Object_Class_MessageQueue].object_list;
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_mq_detach((rt_mq_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_mq_delete((rt_mq_t)object);
			}
		}
#endif

#ifdef RT_USING_MEMPOOL
		/* delete mempools */
		list = &module->module_object[RT_Object_Class_MemPool].object_list;	
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_mp_detach((rt_mp_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_mp_delete((rt_mp_t)object);
			}
		}
#endif

#ifdef RT_USING_DEVICE
		/* delete devices */
		list = &module->module_object[RT_Object_Class_Device].object_list;	
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			rt_device_unregister((rt_device_t)object);
		}
#endif

		/* delete timers */
		list = &module->module_object[RT_Object_Class_Timer].object_list;
		while (list->next != list)
		{
			object = rt_list_entry(list->next, struct rt_object, list);
			if (rt_object_is_systemobject(object) == RT_EOK)
			{
				/* detach static object */
				rt_timer_detach((rt_timer_t)object);
			}
			else
			{
				/* delete dynamic object */
				rt_timer_delete((rt_timer_t)object);
			}
		}
	}

#ifdef RT_USING_SLAB
	if (module->page_cnt > 0)
	{
		struct rt_page_info *page = (struct rt_page_info *)module->page_array;

		rt_kprintf("warning: module memory still hasn't been free finished\n");

		while(module->page_cnt != 0)
		{
			rt_module_free_page(module, page[0].page_ptr, page[0].npage);
		}
	}
#endif

	/* release module space memory */
	rt_free(module->module_space);

	/* release module symbol table */
	for (i=0; i<module->nsym; i++)
		rt_free((void *)module->symtab[i].name);
	if (module->symtab != RT_NULL)
		rt_free(module->symtab);

#ifdef RT_USING_HOOK
	if (rt_module_unload_hook != RT_NULL)
	{
		rt_module_unload_hook(module);
	}
#endif

#ifdef RT_USING_SLAB
	if(module->page_array != RT_NULL) 
		rt_free(module->page_array);
#endif

	/* delete module object */
	rt_object_delete((rt_object_t)module);

	return RT_EOK;
}

/**
 * This function will find the specified module.
 *
 * @param name the name of module finding
 *
 * @return the module
 */
rt_module_t rt_module_find(const char *name)
{
	struct rt_object_information *information;
	struct rt_object *object;
	struct rt_list_node *node;

	extern struct rt_object_information rt_object_container[];

	RT_DEBUG_NOT_IN_INTERRUPT;

	/* enter critical */
	rt_enter_critical();

	/* try to find device object */
	information = &rt_object_container[RT_Object_Class_Module];
	for (node = information->object_list.next; node != &(information->object_list); node = node->next)
	{
		object = rt_list_entry(node, struct rt_object, list);
		if (rt_strncmp(object->name, name, RT_NAME_MAX) == 0)
		{
			/* leave critical */
			rt_exit_critical();

			return (rt_module_t)object;
		}
	}

	/* leave critical */
	rt_exit_critical();

	/* not found */
	return RT_NULL;
}

#ifdef RT_USING_SLAB
/*
 * This function will allocate the numbers page with specified size
 * in page memory.
 *
 * @param size the size of memory to be allocated.
 * @note this function is used for RT-Thread Application Module
 */
static void *rt_module_malloc_page(rt_size_t npages)
{
	void *chunk;
	struct rt_page_info *page;

	chunk = rt_page_alloc(npages);
	if (chunk == RT_NULL)
		return RT_NULL;

	page = (struct rt_page_info *)rt_current_module->page_array;
	page[rt_current_module->page_cnt].page_ptr = chunk;
	page[rt_current_module->page_cnt].npage = npages;
	rt_current_module->page_cnt ++;

	RT_ASSERT(rt_current_module->page_cnt <= PAGE_COUNT_MAX);
	rt_kprintf("rt_module_malloc_page 0x%x %d\n", chunk, npages);

	return chunk;
}

/*
 * This function will release the previously allocated memory page
 * by rt_malloc_page.
 *
 * @param page_ptr the page address to be released.
 * @param npages the number of page shall be released.
 *
 * @note this function is used for RT-Thread Application Module
 */
static void rt_module_free_page(rt_module_t module, void *page_ptr, rt_size_t npages)
{
	int i, index;
	struct rt_page_info *page;

	rt_kprintf("rt_module_free_page 0x%x %d\n", page_ptr, npages);
	rt_page_free(page_ptr, npages);

	page = (struct rt_page_info*)module->page_array;

	for(i=0; i<module->page_cnt; i++)
	{
		if (page[i].page_ptr == page_ptr)
		{
			if (page[i].npage == npages + 1)
			{
				page[i].page_ptr += npages * RT_MM_PAGE_SIZE / sizeof(rt_uint32_t);
				page[i].npage -= npages;
			}
			else if(page[i].npage == npages)
			{
				for(index=i; index<module->page_cnt-1; index++)
				{
					page[index].page_ptr = page[index + 1].page_ptr;
					page[index].npage = page[index + 1].npage;
				}
				page[module->page_cnt - 1].page_ptr = RT_NULL;
				page[module->page_cnt - 1].npage = 0;

				module->page_cnt--;
			}
			else
				RT_ASSERT(RT_FALSE);
			rt_current_module->page_cnt--;

			return;
		}
	}

	/* should not be get here */
	RT_ASSERT(RT_FALSE);
}

/*
  rt_module_malloc - allocate memory block in free list
*/
void *rt_module_malloc(rt_size_t size)
{
	struct rt_mem_head *b, *n, *up;
	struct rt_mem_head **prev;
	rt_uint32_t npage;
	rt_size_t nunits;

	RT_DEBUG_NOT_IN_INTERRUPT;

	nunits = (size + sizeof(struct rt_mem_head) -1)/sizeof(struct rt_mem_head) + 1;

	RT_ASSERT(size != 0);
	RT_ASSERT(nunits != 0);

	rt_sem_take(&mod_sem, RT_WAITING_FOREVER);

	for (prev = (struct rt_mem_head **)&rt_current_module->mem_list; (b = *prev) != RT_NULL; prev = &(b->next))
	{
		if (b->size > nunits)
		{
			/* split memory */
			n = b + nunits;
			n->next = b->next;
			n->size = b->size - nunits;
			b->size = nunits;
			*prev = n;

			rt_kprintf("rt_module_malloc 0x%x, %d\n",b + 1, size);
			rt_sem_release(&mod_sem);

			return (void *)(b + 1);
		}

		if (b->size == nunits)
		{
			/* this node fit, remove this node */
			*prev = b->next;

			rt_kprintf("rt_module_malloc 0x%x, %d\n",b + 1, size);

			rt_sem_release(&mod_sem);

			return (void *)(b + 1);
		}
	}

	/* allocate pages from system heap */
	npage = (size + sizeof(struct rt_mem_head) + RT_MM_PAGE_SIZE - 1)/RT_MM_PAGE_SIZE;
	if ((up = (struct rt_mem_head *)rt_module_malloc_page(npage)) == RT_NULL)
		return RT_NULL;

	up->size = npage * RT_MM_PAGE_SIZE / sizeof(struct rt_mem_head);

	for (prev = (struct rt_mem_head **)&rt_current_module->mem_list; (b = *prev) != RT_NULL; prev = &(b->next))
	{
		if (b > up + up->size)
			break;
	}

	up->next = b;
	*prev = up;

	rt_sem_release(&mod_sem);

	return rt_module_malloc(size);
}

/*
  rt_module_free - free memory block in free list
*/
void rt_module_free(rt_module_t module, void *addr)
{
	struct rt_mem_head *b, *n, *r;
	struct rt_mem_head **prev;

	RT_DEBUG_NOT_IN_INTERRUPT;

	RT_ASSERT(addr);
	RT_ASSERT((((rt_uint32_t)addr) & (sizeof(struct rt_mem_head) -1)) == 0);

	rt_kprintf("rt_module_free 0x%x\n", addr);

	rt_sem_take(&mod_sem, RT_WAITING_FOREVER);

	n = (struct rt_mem_head *)addr - 1;
	prev = (struct rt_mem_head **)&module->mem_list;

	while ((b = *prev) != RT_NULL)
	{
		RT_ASSERT(b->size > 0);
		RT_ASSERT(b > n || b + b->size <= n);

		if (b + b->size == n && ((rt_uint32_t)n % RT_MM_PAGE_SIZE != 0))
		{
			if (b + (b->size + n->size) == b->next)
			{
				b->size += b->next->size + n->size;
				b->next = b->next->next;
			}
			else
				b->size += n->size;

			if ((rt_uint32_t)b % RT_MM_PAGE_SIZE == 0)
			{
				int npage = b->size * sizeof(struct rt_page_info) / RT_MM_PAGE_SIZE;
				if (npage > 0)
				{
					if ((b->size * sizeof(struct rt_page_info) % RT_MM_PAGE_SIZE) != 0)
					{
						rt_size_t nunits = npage * RT_MM_PAGE_SIZE / sizeof(struct rt_mem_head);
						/* split memory */
						r = b + nunits;
						r->next = b->next;
						r->size = b->size - nunits;
						*prev = r;
					}
					else
					{
						*prev = b->next;
					}

					rt_module_free_page(module, b, npage);
				}
			}

			/* unlock */
			rt_sem_release(&mod_sem);

			return;
		}

		if (b == n + n->size)
		{
			n->size = b->size + n->size;
			n->next = b->next;

			if ((rt_uint32_t)n % RT_MM_PAGE_SIZE == 0)
			{
				int npage = n->size * sizeof(struct rt_page_info) / RT_MM_PAGE_SIZE;
				if (npage > 0)
				{
					if ((n->size * sizeof(struct rt_page_info) % RT_MM_PAGE_SIZE) != 0)
					{
						rt_size_t nunits = npage * RT_MM_PAGE_SIZE / sizeof(struct rt_mem_head);
						/* split memory */
						r = n + nunits;
						r->next = n->next;
						r->size = n->size - nunits;
						*prev = r;
					}
					else *prev = n->next;

					rt_module_free_page(module, n, npage);
				}
			}
			else
			{
				*prev = n;
			}

			/* unlock */
			rt_sem_release(&mod_sem);

			return;
		}
		if (b > n + n->size)
			break;

		prev = &(b->next);
	}

	if ((rt_uint32_t)n % RT_MM_PAGE_SIZE == 0)
	{
		int npage = n->size * sizeof(struct rt_page_info) / RT_MM_PAGE_SIZE;
		if (npage > 0)
		{
			rt_module_free_page(module, n, npage);
			if (n->size % RT_MM_PAGE_SIZE != 0)
			{
				rt_size_t nunits = npage * RT_MM_PAGE_SIZE / sizeof(struct rt_mem_head);
				/* split memory */
				r = n + nunits;
				r->next = b;
				r->size = n->size - nunits;
				*prev = r;
			}
			else
			{
				*prev = b;
			}
		}
	}
	else
	{
		n->next = b;
		*prev = n;
	}

	/* unlock */
	rt_sem_release(&mod_sem);
}

/*
  rt_module_realloc - realloc memory block in free list
*/
void *rt_module_realloc(void *ptr, rt_size_t size)
{
	struct rt_mem_head *b, *p, *prev, *tmpp;
	rt_size_t nunits;

	RT_DEBUG_NOT_IN_INTERRUPT;

	if (!ptr)
		return rt_module_malloc(size);
	if (size == 0)
	{
		rt_module_free(rt_current_module, ptr);

		return RT_NULL;
	}

	nunits = (size + sizeof(struct rt_mem_head) - 1) / sizeof(struct rt_mem_head) + 1;
	b = (struct rt_mem_head *)ptr - 1;

	if (nunits <= b->size)
	{
		/* new size is smaller or equal then before */
		if (nunits == b->size)
			return ptr;
		else
		{
			p = b + nunits;
			p->size = b->size - nunits;
			b->size = nunits;
			rt_module_free(rt_current_module, (void *)(p + 1));

			return (void *)(b + 1);
		}
	}
	else
	{
		/* more space then required */
		prev = (struct rt_mem_head *)rt_current_module->mem_list;
		for (p = prev->next; p != (b->size + b) && p != RT_NULL; prev = p, p = p->next)
			break;

		/* available block after ap in freelist */ 
		if (p != RT_NULL && (p->size >= (nunits - (b->size))) &&  p == (b + b->size))  
		{
			/* perfect match */
			if (p->size == (nunits - (b->size)))  
			{
				b->size = nunits;
				prev->next = p->next;
			}
			else  /* more space then required, split block*/
			{
				/* pointer to old header */
				tmpp = p;
				p = b + nunits;

				/* restoring old pointer */
				p->next = tmpp->next;
				
				/* new size for p */
				p->size = tmpp->size + b->size - nunits;
				b->size = nunits;
				prev->next = p;
			}
			rt_current_module->mem_list = (void *)prev;

			return (void *)(b + 1);
		}
		else /* allocate new memory and copy old data */
		{
			if ((p = rt_module_malloc(size)) == RT_NULL) return RT_NULL;
			rt_memmove(p, (b+1), ((b->size) * sizeof(struct rt_mem_head)));
			rt_module_free(rt_current_module, (void *)(b + 1));

			return (void *)(p);
		}
	}
}

#ifdef RT_USING_FINSH
#include <finsh.h>
void list_memlist(const char *name)
{
	rt_module_t module;
	struct rt_mem_head **prev;
	struct rt_mem_head *b;

	module = rt_module_find(name);
	if (module == RT_NULL)
		return;

	for (prev = (struct rt_mem_head **)&module->mem_list; (b = *prev) != RT_NULL; prev = &(b->next))
	{
		rt_kprintf("0x%x--%d\n", b, b->size * sizeof(struct rt_mem_head));
	}
}
FINSH_FUNCTION_EXPORT(list_memlist, list module free memory information)

void list_mempage(const char *name)
{
	rt_module_t module;
	struct rt_page_info *page;
	int i;

	module = rt_module_find(name);
	if (module == RT_NULL)
		return;

	page = (struct rt_page_info*)module->page_array;

	for (i=0; i<module->page_cnt; i++)
	{
		rt_kprintf("0x%x--%d\n", page[i].page_ptr, page[i].npage);
	}
}
FINSH_FUNCTION_EXPORT(list_mempage, list module using memory page information)
#endif

#endif

#endif