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 static int _stp_kta(unsigned long addr);
  27
  28 #if defined (__x86_64__)
  29 #include "stack-x86_64.c"
  30 #elif defined (__ia64__)
  31 #include "stack-ia64.c"
  32 #elif  defined (__i386__)
  33 #include "stack-i386.c"
  34 #elif defined (__powerpc64__)
  35 #include "stack-ppc64.c"
  36 #elif defined (__s390__) || defined (__s390x__)
  37 #include "stack-s390.c"
  38 #else
  39 #error "Unsupported architecture"
  40 #endif
  41
  42
  43 /* our copy of kernel_text_address() */
  44 static int _stp_kta(unsigned long addr)
  45 {
  46         static unsigned long stext, etext, sinittext, einittext;
  47         static int init = 0;
  48
  49         if (init == 0) {
  50                 init = 1;
  51                 etext = _stp_kallsyms_lookup_name("_etext");
  52                 stext = _stp_kallsyms_lookup_name("_stext");
  53                 sinittext = _stp_kallsyms_lookup_name("_sinittext");
  54                 einittext = _stp_kallsyms_lookup_name("_einittext");
  55         }
  56
  57         if (addr >= stext && addr <= etext)
  58                 return 1;
  59
  60         if (addr >= sinittext && addr <= einittext)
  61                 return 1;
  62
  63         return 0;
  64 }
  65
  66 /** Prints the stack backtrace
  67  * @param regs A pointer to the struct pt_regs.
  68  */
  69
  70 void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
  71 {
  72         if (verbose) {
  73                 /* print the current address */
  74                 if (pi) {
  75                         _stp_print("Returning from: ");
  76                         _stp_symbol_print((unsigned long)_stp_probe_addr_r(pi));
  77                         _stp_print("\nReturning to  : ");
  78                         _stp_symbol_print((unsigned long)_stp_ret_addr_r(pi));
  79                 } else {
  80                         _stp_print_char(' ');
  81                         _stp_symbol_print (REG_IP(regs));
  82                 }
  83                 _stp_print_char('\n');
  84         } else
  85                 _stp_printf ("%p ", REG_IP(regs));
  86         __stp_stack_print (regs, verbose, 0);
  87 }
  88
  89 /** Writes stack backtrace to a string
  90  *
  91  * @param str string
  92  * @param regs A pointer to the struct pt_regs.
  93  * @returns void
  94  */
  95 void _stp_stack_snprint (char *str, int size, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
  96 {
  97         /* To get a string, we use a simple trick. First flush the print buffer, */
  98         /* then call _stp_stack_print, then copy the result into the output string  */
  99         /* and clear the print buffer. */
 100         _stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
 101         _stp_print_flush();
 102         _stp_stack_print(regs, verbose, pi);
 103         strlcpy(str, pb->buf, size < pb->len ? size : pb->len);
 104         pb->len = 0;
 105 }
 106
 107
 108 /** Prints the user stack backtrace
 109  * @param str string
 110  * @returns Same string as was input with trace info appended,
 111  * @note Currently limited to a depth of two. Works from jprobes and kprobes.
 112  */
 113 #if 0
 114 void _stp_ustack_print (char *str)
 115 {
 116         struct pt_regs *nregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) current->thread_info)) - 1;
 117         _stp_printf ("%p : [user]\n", REG_IP(nregs));
 118         if (REG_SP(nregs))
 119                 _stp_printf ("%p : [user]\n", *(unsigned long *)REG_SP(nregs));
 120 }
 121 #endif /* 0 */
 122
 123 /** @} */
 124 #endif /* _STACK_C_ */