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/* -*- linux-c -*-
* i386 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.
*/
static int _stp_valid_stack_ptr(unsigned long context, unsigned long p)
{
return p > context && p < context + THREAD_SIZE - 3;
}
/* DWARF unwinder failed. Just dump intereting addresses on kernel stack. */
static void _stp_stack_print_fallback(unsigned long context, unsigned long stack, int verbose)
{
unsigned long addr;
while (_stp_valid_stack_ptr(context, stack)) {
if (unlikely(_stp_read_address(addr, (unsigned long *)stack, KERNEL_DS))) {
/* cannot access stack. give up. */
return;
}
_stp_func_print(addr, verbose, 0);
stack++;
}
}
static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels)
{
unsigned long *stack = (unsigned long *)®_SP(regs);
unsigned long context = (unsigned long)stack & ~(THREAD_SIZE - 1);
#ifdef CONFIG_FRAME_POINTER
/* FIXME: need to use _stp_func_print() and safe copy */
unsigned long addr;
#ifdef STAPCONF_X86_UNIREGS
unsigned long ebp = regs->bp;
#else
unsigned long ebp = regs->ebp;
#endif /* STAPCONF_X86_UNIREGS */
while (_stp_valid_stack_ptr(context, (unsigned long)ebp)) {
if (unlikely(_stp_read_address(addr, (unsigned long *)(ebp + 4), KERNEL_DS))) {
/* cannot access stack. give up. */
return;
}
if (verbose) {
_stp_print_char(' ');
_stp_symbol_print (addr);
_stp_print_char('\n');
} else
_stp_printf ("0x%08lx ", addr);
ebp = *(unsigned long *)ebp;
}
#else
struct unwind_frame_info info;
arch_unw_init_frame_info(&info, regs);
while (!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);
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);
break;
}
#endif /* CONFIG_FRAME_POINTER */
}
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