static int get_frame_info(struct mips_frame_info *info)
{
union mips_instruction *ip = info->func;
int i, max_insns =
min(128UL, info->func_size / sizeof(union mips_instruction));
info->pc_offset = -1;
info->frame_size = 0;
for (i = 0; i < max_insns; i++, ip++) {
if (is_jal_jalr_jr_ins(ip))
break;
if (!info->frame_size) {
if (is_sp_move_ins(ip))
info->frame_size = - ip->i_format.simmediate;
continue;
}
if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
info->pc_offset =
ip->i_format.simmediate / sizeof(long);
break;
}
}
if (info->frame_size && info->pc_offset >= 0) /* nested */
return 0;
if (info->pc_offset < 0) /* leaf */
return 1;
/* prologue seems boggus... */
return -1;
}
static inline int unwind_user_frame(struct stackframe *old_frame,
const unsigned int max_instr_check)
{
struct stackframe new_frame = *old_frame;
off_t ra_offset = 0;
size_t stack_size = 0;
unsigned long addr;
if (old_frame->pc == 0 || old_frame->sp == 0 || old_frame->ra == 0)
return -9;
for (addr = new_frame.pc; (addr + max_instr_check > new_frame.pc)
&& (!ra_offset || !stack_size); --addr) {
union mips_instruction ip;
if (get_mem(addr, (unsigned long *) &ip))
return -11;
if (is_sp_move_ins(&ip)) {
int stack_adjustment = ip.i_format.simmediate;
if (stack_adjustment > 0)
/* This marks the end of the previous function,
which means we overran. */
break;
stack_size = (unsigned long) stack_adjustment;
} else if (is_ra_save_ins(&ip)) {
int ra_slot = ip.i_format.simmediate;
if (ra_slot < 0)
/* This shouldn't happen. */
break;
ra_offset = ra_slot;
} else if (is_end_of_function_marker(&ip))
break;
}
if (!ra_offset || !stack_size)
goto done;
if (ra_offset) {
new_frame.ra = old_frame->sp + ra_offset;
if (get_mem(new_frame.ra, &(new_frame.ra)))
return -13;
}
if (stack_size) {
new_frame.sp = old_frame->sp + stack_size;
if (get_mem(new_frame.sp, &(new_frame.sp)))
return -14;
}
if (new_frame.sp > old_frame->sp)
return -2;
done:
new_frame.pc = old_frame->ra;
*old_frame = new_frame;
return 0;
}
static int get_frame_info(struct mips_frame_info *info)
{
union mips_instruction *ip = info->func;
unsigned max_insns = info->func_size / sizeof(union mips_instruction);
unsigned i;
info->pc_offset = -1;
info->frame_size = 0;
if (!ip)
goto err;
if (max_insns == 0)
max_insns = 128U; /* */
max_insns = min(128U, max_insns);
for (i = 0; i < max_insns; i++, ip++) {
if (is_jal_jalr_jr_ins(ip))
break;
if (!info->frame_size) {
if (is_sp_move_ins(ip))
info->frame_size = - ip->i_format.simmediate;
continue;
}
if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
info->pc_offset =
ip->i_format.simmediate / sizeof(long);
break;
}
}
if (info->frame_size && info->pc_offset >= 0) /* */
return 0;
if (info->pc_offset < 0) /* */
return 1;
/* */
err:
return -1;
}