Function unwind_frame

libcpu/arm/cortex-a/backtrace.c:381–480

* Unwind a single frame starting with *sp for the symbol at *pc. It * updates the *pc and *sp with the new values. */

 * updates the *pc and *sp with the new values.
 */
int unwind_frame(struct stackframe *frame, const struct unwind_idx **origin_idx, const struct unwind_idx exidx_start[], const struct unwind_idx exidx_end[])
{
    unsigned long low;
    const struct unwind_idx *idx;
    struct unwind_ctrl_block ctrl;
    struct rt_thread *rt_c_thread;

    /* store the highest address on the stack to avoid crossing it*/
    low = frame->sp;
    rt_c_thread = rt_thread_self();
    ctrl.sp_high = (unsigned long)((char*)rt_c_thread->stack_addr + rt_c_thread->stack_size);

    LOG_D("%s(pc = %08lx lr = %08lx sp = %08lx)", __func__,
            frame->pc, frame->lr, frame->sp);

    idx = unwind_find_idx(frame->pc, origin_idx, exidx_start, exidx_end);
    if (!idx)
    {
        LOG_W("unwind: Index not found %08lx", frame->pc);
        return -URC_FAILURE;
    }

#ifdef RT_BACKTRACE_FUNCTION_NAME
    {
        char *fun_name;
        fun_name = unwind_get_function_name((void *)prel31_to_addr(&idx->addr_offset));
        if (fun_name)
        {
            rt_kprintf("0x%08x @ %s\n", frame->pc, fun_name);
        }
    }
#endif

    ctrl.vrs[FP] = frame->fp;
    ctrl.vrs[SP] = frame->sp;
    ctrl.vrs[LR] = frame->lr;
    ctrl.vrs[PC] = 0;

    if (idx->insn == 1)
        /* can't unwind */
        return -URC_FAILURE;
    else if ((idx->insn & 0x80000000) == 0)
        /* prel31 to the unwind table */
        ctrl.insn = (unsigned long *)prel31_to_addr(&idx->insn);
    else if ((idx->insn & 0xff000000) == 0x80000000)
        /* only personality routine 0 supported in the index */
        ctrl.insn = &idx->insn;
    else
    {
        LOG_W("unwind: Unsupported personality routine %08lx in the index at %x",
                idx->insn, idx);
        return -URC_FAILURE;
    }

    /* check the personality routine */
    if ((*ctrl.insn & 0xff000000) == 0x80000000)
    {
        ctrl.byte = 2;