Function db_nextframe

freebsd/i386/i386/db_trace.c:295–433

* Figure out the next frame up in the call stack. */

 * Figure out the next frame up in the call stack.
 */
static void
db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
{
	struct trapframe *tf;
	int frame_type;
	int eip, esp, ebp;
	db_expr_t offset;
	c_db_sym_t sym;
	const char *name;

	eip = db_get_value((int) &(*fp)->f_retaddr, 4, false);
	ebp = db_get_value((int) &(*fp)->f_frame, 4, false);

	/*
	 * Figure out frame type.  We look at the address just before
	 * the saved instruction pointer as the saved EIP is after the
	 * call function, and if the function being called is marked as
	 * dead (such as panic() at the end of dblfault_handler()), then
	 * the instruction at the saved EIP will be part of a different
	 * function (syscall() in this example) rather than the one that
	 * actually made the call.
	 */
	frame_type = NORMAL;

	if (eip >= PMAP_TRM_MIN_ADDRESS) {
		sym = db_search_symbol(eip - 1 - setidt_disp, DB_STGY_ANY,
		    &offset);
	} else {
		sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
	}
	db_symbol_values(sym, &name, NULL);
	if (name != NULL) {
		if (strcmp(name, "calltrap") == 0 ||
		    strcmp(name, "fork_trampoline") == 0)
			frame_type = TRAP;
		else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
		    strncmp(name, "Xapic_isr", 9) == 0) {
			frame_type = INTERRUPT;
		} else if (strcmp(name, "Xlcall_syscall") == 0 ||
		    strcmp(name, "Xint0x80_syscall") == 0)
			frame_type = SYSCALL;
		else if (strcmp(name, "dblfault_handler") == 0)
			frame_type = DOUBLE_FAULT;
		else if (strcmp(name, "Xtimerint") == 0 ||
		    strcmp(name, "Xxen_intr_upcall") == 0)
			frame_type = INTERRUPT;
		else if (strcmp(name, "Xcpustop") == 0 ||
		    strcmp(name, "Xrendezvous") == 0 ||
		    strcmp(name, "Xipi_intr_bitmap_handler") == 0) {
			/* No arguments. */
			frame_type = INTERRUPT;
		}
	}

	/*
	 * Normal frames need no special processing.
	 */
	if (frame_type == NORMAL) {