/*
* NOTE:
* Expect the breakpoint instruction to be the smallest size instruction for
* the architecture. If an arch has variable length instruction and the
* breakpoint instruction is not of the smallest length instruction
* supported by that architecture then we need to modify is_trap_at_addr and
* uprobe_write_opcode accordingly. This would never be a problem for archs
* that have fixed length instructions.
*
* uprobe_write_opcode - write the opcode at a given virtual address.
* @mm: the probed process address space.
* @vaddr: the virtual address to store the opcode.
* @opcode: opcode to be written at @vaddr.
*
* Called with mm->mmap_sem held for write.
* Return 0 (success) or a negative errno.
*/
int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr,
uprobe_opcode_t opcode)
{
struct page *old_page, *new_page;
struct vm_area_struct *vma;
int ret;
retry:
/* Read the page with vaddr into memory */
ret = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &old_page,
&vma);
if (ret <= 0)
return ret;
ret = verify_opcode(old_page, vaddr, &opcode);
if (ret <= 0)
goto put_old;
ret = anon_vma_prepare(vma);
if (ret)
goto put_old;
ret = -ENOMEM;
new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
if (!new_page)
goto put_old;
__SetPageUptodate(new_page);
copy_highpage(new_page, old_page);
copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
ret = __replace_page(vma, vaddr, old_page, new_page);
put_page(new_page);
put_old:
put_page(old_page);
if (unlikely(ret == -EAGAIN))
goto retry;
return ret;
}
static int masm_main_loop(char * obj_file,char * src_file)
{
FILE * obj_fp, *src_fp;
char buf[BUFSIZ] = {0};
int length;
char * p, * q;
src_fp = obj_fp = NULL;
uint32_t counter = 0;
uint32_t lines = 0;
hash_table * label_hash = hash_create(512);
char op_name[128];
char label[128];
char rd[6];
char rs[6];
char rt[6];
char imm[20];
int32_t rd_num,rs_num,rt_num,imm_num;
if((src_fp = fopen(src_file,"r")) == NULL)
{
printf("Can not open %s:%s\n",src_file,strerror(errno));
}
if((obj_fp = fopen(obj_file,"w+")) == NULL)
{
printf("Can not open %s:%s\n",obj_file,strerror(errno));
}
int total_lines = get_file_lines(src_fp);
uint32_t * instruction = calloc(1,total_lines * sizeof(uint32_t));
var_t * var = calloc(1,total_lines * sizeof(var_t));
int var_count = 0;
fseek(src_fp,0L,SEEK_SET);
while(1)
{
fgets(buf,BUFSIZ,src_fp);
if(feof(src_fp))
{
break;
}
lines++;
length = strlen(buf);
p = buf;
//skip whitespace
while(length > 0 &&isspace(p[0]))
{
length--;
p++;
}
//printf("length=%d\t%s",length,buf+i);
if(p[0] == ';' || p[0] == '\0')
{
continue;
}
q = get_first_token(p);
strncpy(op_name, p , q-p);
op_name[q-p] = '\0';
if(line_has_label(p))
{
/* it is label */
label_t l;
l.name = op_name;
l.real_line = lines;
l.line = counter;
hash_add_item(&label_hash,str2hash(op_name),&l);
p = skip_label_wthie(q);
/* 获得字符串 */
q = get_opcode_token(p);
strncpy(op_name, p , q-p);
op_name[q-p] = '\0';
//printf("%s",op_name);
}
/* p now a opcode start q-p is opecode */
int op_index = verify_opcode(op_name,lines);
q = skip_wthie(q);
p = q;
/* now at rd */
switch(op_index)
{
#if 1
case ADD:
case SUB:
case MUL:
case DIV:
case MOD:
case AND:
case OR:
case NOT:
case XOR:
case LWORD:
case SWORD:
/* 获得字符串 */
q = get_reg_token(p);
strncpy(rd, p , q-p);
rd[q-p] = '\0';
q = skip_reg_wthie(q);
p = q;
q = get_reg_token(p);
strncpy(rs, p , q-p);
rs[q-p] = '\0';
q = skip_reg_wthie(q);
p = q;
q = get_reg_token(p);
strncpy(rt, p , q-p);
rt[q-p] = '\0';
rd_num = get_reg_index(rd,lines);
rs_num = get_reg_index(rs,lines);
rt_num = get_reg_index(rt,lines);
instruction[counter] = (op_index << 26) | (rd_num << 21) | (rs_num << 16)| (rt_num << 11);
break;
///C语言中的左移就是逻辑左移，而右移，
///对于无符号数来说就是逻辑右移，
///对有符号来说就是算术右移
///想要实现符号左移，比较麻烦一点，首先保存最高位，然后左移之后补上最高位。
case SLL:
case SLR:
case SAL:
case SAR:
case ADDI:
case ANDI: ///这里的立即数是0扩展的。
case ORI:
case XORI:
case LUI: ///哦，载入高16位数啊，靠，那么低位怎么载入呢？用ori
q = get_reg_token(p);
strncpy(rd, p , q-p);
rd[q-p] = '\0';
q = skip_reg_wthie(q);
p = q;
q = get_reg_token(p);
strncpy(rs, p , q-p);
rs[q-p] = '\0';
q = skip_reg_wthie(q);
p = q;
q = get_reg_token(p);
strncpy(imm, p , q-p);
imm[q-p] = '\0';
rd_num = get_reg_index(rd,lines);
rs_num = get_reg_index(rs,lines);
imm_num = atoi(imm);
if(imm_num > 32767 || imm_num < -32768)
{
printf("________\n");
printf("[ERROR 6] line: %d imm num is too lager or too smaller\n",lines);
}
instruction[counter] = (op_index << 26) | (rd_num << 21) | (rs_num << 16)| (imm_num & 0x0000ffff);
break;
case LESS:
case GREAT:
case LESSE:
case GREATE:
case LESSU:
case GREATU:
case LESSEU:
case GREATEU:
case EQUAL:
case UEQUAL:
q = get_reg_token(p);
strncpy(rd, p , q-p);
rd[q-p] = '\0';
q = skip_reg_wthie(q);
p = q;
q = get_reg_token(p);
strncpy(rs, p , q-p);
rs[q-p] = '\0';
q = skip_reg_wthie(q);
p = q;
q = get_reg_token(p);
strncpy(label, p , q-p);
label[q-p] = '\0';
rd_num = get_reg_index(rd,lines);
rs_num = get_reg_index(rs,lines);
var[var_count].name = malloc(strlen(label) + 1);
strcpy(var[var_count].name, label);
var[var_count].line = counter;
var_count++;
instruction[counter] = (op_index << 26) | (rd_num << 21) | (rs_num << 16) | 0x0;
break;
case JMP:
q = get_reg_token(p);
strncpy(label, p , q-p);
label[q-p] = '\0';
var[var_count].name = malloc(strlen(label) + 1);
strcpy(var[var_count].name, label);
var[var_count].line = counter;
var_count++;
instruction[counter] = (op_index << 26);
break;
/* 存储指令 */
case MOV:
q = get_reg_token(p);
strncpy(rd, p , q-p);
rd[q-p] = '\0';
q = skip_reg_wthie(q);
p = q;
q = get_reg_token(p);
strncpy(rs, p , q-p);
rs[q-p] = '\0';
rd_num = get_reg_index(rd,lines);
rs_num = get_reg_index(rs,lines);
instruction[counter] = (op_index << 26) | (rd_num << 21) | (rs_num << 16) | 0x0;
break;
default:
break;
#endif
}
counter++;
}
/* 第二趟汇编 */
struct blist * head;
for(int i = 0; i < var_count; i++)
{
if((head = hash_lookup_item(label_hash,str2hash(var[i].name),&var[i])) != NULL)
{
label_t * node = head->item;
int imm_2 = node->line - var[i].line;
if((instruction[var[i].line] >> 26) == JMP)
{
if(imm_2 > 33554431 || imm_2 < -33554432)
{
printf("[ERROR 7] line: %d imm num is too lager or too smaller\n",lines);
}
instruction[var[i].line] |= imm_2 & 0x03ffffff;
}
else
{
if(imm_2 > 32767 || imm_2 < -32768)
{
printf("[ERROR 6] line: %d imm num is too lager or too smaller\n",lines);
}
instruction[var[i].line] |= imm_2 & 0x0000ffff;
}
}
