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/* -*- linux-c -*-
* Stack tracing functions
* Copyright (C) 2005, 2006 Red Hat Inc.
* Copyright (C) 2005 Intel Corporation.
*
* 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.
*/
#ifndef _STACK_C_
#define _STACK_C_
/** @file stack.c
* @brief Stack Tracing Functions
*/
/** @addtogroup stack Stack Tracing Functions
* Without frames the best that can be done here is to scan the stack and
* display everything that fits in the range of a valid IP. Things like function pointers
* on the stack will certainly result in bogus addresses in the backtrace.
*
* With debug info, we could get a proper backtrace, but it would be too slow to do
* during a probe. We can eventually make this a postprocessing feature.
*
* @{
*/
#include "sym.c"
#include "regs.h"
static int _stp_kta(unsigned long addr);
#if defined (__x86_64__)
#include "stack-x86_64.c"
#elif defined (__ia64__)
#include "stack-ia64.c"
#elif defined (__i386__)
#include "stack-i386.c"
#elif defined (__powerpc64__)
#include "stack-ppc64.c"
#else
#error "Unsupported architecture"
#endif
/* our copy of kernel_text_address() */
static int _stp_kta(unsigned long addr)
{
static unsigned long stext, etext, sinittext, einittext;
static int init = 0;
if (init == 0) {
init = 1;
etext = _stp_kallsyms_lookup_name("_etext");
stext = _stp_kallsyms_lookup_name("_stext");
sinittext = _stp_kallsyms_lookup_name("_sinittext");
einittext = _stp_kallsyms_lookup_name("_einittext");
}
if (addr >= stext && addr <= etext)
return 1;
if (addr >= sinittext && addr <= einittext)
return 1;
return 0;
}
/** Writes stack backtrace to a String
*
* @param str String
* @param regs A pointer to the struct pt_regs.
* @returns Same String as was input with trace info appended,
*/
String _stp_stack_sprint (String str, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
{
if (verbose) {
/* print the current address */
if (pi) {
_stp_string_cat(str, "Returning from: ");
_stp_symbol_sprint(str, (unsigned long)_stp_probe_addr_r(pi));
_stp_string_cat(str, "\nReturning to: ");
_stp_symbol_sprint(str, (unsigned long)_stp_ret_addr_r(pi));
} else
_stp_symbol_sprint (str, REG_IP(regs));
_stp_string_cat(str, "\n");
} else
_stp_sprintf (str, "%lx ", REG_IP(regs));
__stp_stack_sprint (str, regs, verbose, 0);
return str;
}
/** Prints the stack backtrace
* @param regs A pointer to the struct pt_regs.
*/
#define _stp_stack_print(regs,pi) (void)_stp_stack_sprint(_stp_stdout,regs,1,pi)
/** Writes stack backtrace to a String.
* Use this when calling from a jprobe.
* @param str String
* @returns Same String as was input with trace info appended,
* @sa _stp_stack_sprint()
*/
String _stp_stack_sprintj(String str)
{
unsigned long stack;
_stp_sprintf (str, "trace for %d (%s)\n", current->pid, current->comm);
/* __stp_stack_sprint (str, &stack, 1, 0); */
return str;
}
/** Prints the stack backtrace.
* Use this when calling from a jprobe.
* @sa _stp_stack_print()
*/
#define _stp_stack_printj() (void)_stp_stack_sprintj(_stp_stdout)
/** Writes the user stack backtrace to a String
* @param str String
* @returns Same String as was input with trace info appended,
* @note Currently limited to a depth of two. Works from jprobes and kprobes.
*/
String _stp_ustack_sprint (String str)
{
struct pt_regs *nregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) current->thread_info)) - 1;
#if BITS_PER_LONG == 64
_stp_sprintf (str, " 0x%016lx : [user]\n", REG_IP(nregs));
if (REG_SP(nregs))
_stp_sprintf (str, " 0x%016lx : [user]\n", *(unsigned long *)REG_SP(nregs));
#else
_stp_sprintf (str, " 0x%08lx : [user]\n", REG_IP(nregs));
if (REG_SP(nregs))
_stp_sprintf (str, " 0x%08lx : [user]\n", *(unsigned long *)REG_SP(nregs));
#endif
return str;
}
/** Prints the user stack backtrace
* @note Currently limited to a depth of two. Works from jprobes and kprobes.
*/
#define _stp_ustack_print() (void)_stp_ustack_sprint(_stp_stdout)
/** @} */
#endif /* _STACK_C_ */
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