runtime/stack.c

   1 /*  -*- linux-c -*-
   2  * Stack tracing functions
   3  * Copyright (C) 2005, 2006, 2007 Red Hat Inc.
   4  * Copyright (C) 2005 Intel Corporation.
   5  *
   6  * This file is part of systemtap, and is free software.  You can
   7  * redistribute it and/or modify it under the terms of the GNU General
   8  * Public License (GPL); either version 2, or (at your option) any
   9  * later version.
  10  */
  11
  12 #ifndef _STACK_C_
  13 #define _STACK_C_
  14
  15 /** @file stack.c
  16  * @brief Stack Tracing Functions
  17  */
  18
  19 /** @addtogroup stack Stack Tracing Functions
  20  *
  21  * @{
  22  */
  23
  24 #include "sym.c"
  25 #include "regs.h"
  26
  27 #define MAXBACKTRACE 20
  28
  29 #if defined (__x86_64__)
  30 #include "stack-x86_64.c"
  31 #elif defined (__ia64__)
  32 #include "stack-ia64.c"
  33 #elif  defined (__i386__)
  34 #include "stack-i386.c"
  35 #elif defined (__powerpc64__)
  36 #include "stack-ppc64.c"
  37 #elif defined (__arm__)
  38 #include "stack-arm.c"
  39 #elif defined (__s390__) || defined (__s390x__)
  40 #include "stack-s390.c"
  41 #else
  42 #error "Unsupported architecture"
  43 #endif
  44
  45 /** Prints the stack backtrace
  46  * @param regs A pointer to the struct pt_regs.
  47  */
  48
  49 void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
  50 {
  51         if (verbose) {
  52                 /* print the current address */
  53                 if (pi) {
  54                         _stp_print("Returning from: ");
  55                         _stp_symbol_print((unsigned long)_stp_probe_addr_r(pi));
  56                         _stp_print("\nReturning to  : ");
  57                         _stp_symbol_print((unsigned long)_stp_ret_addr_r(pi));
  58                 } else {
  59                         _stp_print_char(' ');
  60                         _stp_symbol_print (REG_IP(regs));
  61                 }
  62                 _stp_print_char('\n');
  63         } else
  64                 _stp_printf ("%p ", (int64_t)REG_IP(regs));
  65         __stp_stack_print (regs, verbose, 0);
  66 }
  67
  68 /** Writes stack backtrace to a string
  69  *
  70  * @param str string
  71  * @param regs A pointer to the struct pt_regs.
  72  * @returns void
  73  */
  74 void _stp_stack_snprint (char *str, int size, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
  75 {
  76         /* To get a string, we use a simple trick. First flush the print buffer, */
  77         /* then call _stp_stack_print, then copy the result into the output string  */
  78         /* and clear the print buffer. */
  79         _stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
  80         _stp_print_flush();
  81         _stp_stack_print(regs, verbose, pi);
  82         strlcpy(str, pb->buf, size < (int)pb->len ? size : (int)pb->len);
  83         pb->len = 0;
  84 }
  85
  86
  87 /** Prints the user stack backtrace
  88  * @param str string
  89  * @returns Same string as was input with trace info appended,
  90  * @note Currently limited to a depth of two. Works from jprobes and kprobes.
  91  */
  92 #if 0
  93 void _stp_ustack_print (char *str)
  94 {
  95         struct pt_regs *nregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) current->thread_info)) - 1;
  96         _stp_printf ("%p : [user]\n", (int64_t)REG_IP(nregs));
  97         if (REG_SP(nregs))
  98                 _stp_printf ("%p : [user]\n", (int64_t)(*(unsigned long *)REG_SP(nregs)));
  99 }
 100 #endif /* 0 */
 101
 102 /** @} */
 103 #endif /* _STACK_C_ */