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/* -*- linux-c -*-
* x86_64 stack tracing functions
* Copyright (C) 2005-2008 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
/* DWARF unwinder failed. Just dump intereting addresses on kernel stack. */
#ifndef CONFIG_STACKTRACE
static void _stp_stack_print_fallback(unsigned long stack, int verbose, int levels)
{
unsigned long addr;
while (levels && stack & (THREAD_SIZE - 1)) {
if (unlikely(_stp_read_address(addr, (unsigned long *)stack, KERNEL_DS))) {
/* cannot access stack. give up. */
return;
}
if (_stp_func_print(addr, verbose, 0))
levels--;
stack++;
}
}
#endif
static void __stp_stack_print(struct pt_regs *regs, int verbose, int levels)
{
#ifdef STP_USE_DWARF_UNWINDER
// FIXME: large stack allocation
struct unwind_frame_info info;
arch_unw_init_frame_info(&info, regs);
while (levels && !arch_unw_user_mode(&info)) {
int ret = unwind(&info);
dbug_unwind(1, "ret=%d PC=%lx SP=%lx\n", ret, UNW_PC(&info), UNW_SP(&info));
if (ret == 0) {
_stp_func_print(UNW_PC(&info), verbose, 1);
levels--;
continue;
}
/* If an error happened or we hit a kretprobe trampoline, use fallback backtrace */
/* FIXME: is there a way to unwind across kretprobe trampolines? */
if (ret < 0 || (ret > 0 && UNW_PC(&info) == _stp_kretprobe_trampoline))
_stp_stack_print_fallback(UNW_SP(&info), verbose, levels);
break;
}
#else /* ! STP_USE_DWARF_UNWINDER */
_stp_stack_print_fallback(REG_SP(regs), verbose, levels);
#endif
}
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