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 #define MAXBACKTRACE 20
  29
  30 #if defined (__x86_64__)
  31 #include "stack-x86_64.c"
  32 #elif defined (__ia64__)
  33 #include "stack-ia64.c"
  34 #elif  defined (__i386__)
  35 #include "stack-i386.c"
  36 #elif defined (__powerpc64__)
  37 #include "stack-ppc64.c"
  38 #elif defined (__s390__) || defined (__s390x__)
  39 #include "stack-s390.c"
  40 #else
  41 #error "Unsupported architecture"
  42 #endif
  43
  44
  45 /* our copy of kernel_text_address() */
  46 static int _stp_kta(unsigned long addr)
  47 {
  48         static unsigned long stext, etext, sinittext, einittext;
  49         static int init = 0;
  50
  51         if (init == 0) {
  52                 init = 1;
  53                 etext = _stp_kallsyms_lookup_name("_etext");
  54                 stext = _stp_kallsyms_lookup_name("_stext");
  55                 sinittext = _stp_kallsyms_lookup_name("_sinittext");
  56                 einittext = _stp_kallsyms_lookup_name("_einittext");
  57         }
  58
  59         if (addr >= stext && addr <= etext)
  60                 return 1;
  61
  62         if (addr >= sinittext && addr <= einittext)
  63                 return 1;
  64
  65         return 0;
  66 }
  67
  68 /** Prints the stack backtrace
  69  * @param regs A pointer to the struct pt_regs.
  70  */
  71
  72 void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
  73 {
  74         if (verbose) {
  75                 /* print the current address */
  76                 if (pi) {
  77                         _stp_print("Returning from: ");
  78                         _stp_symbol_print((unsigned long)_stp_probe_addr_r(pi));
  79                         _stp_print("\nReturning to  : ");
  80                         _stp_symbol_print((unsigned long)_stp_ret_addr_r(pi));
  81                 } else {
  82                         _stp_print_char(' ');
  83                         _stp_symbol_print (REG_IP(regs));
  84                 }
  85                 _stp_print_char('\n');
  86         } else
  87                 _stp_printf ("%p ", REG_IP(regs));
  88         __stp_stack_print (regs, verbose, 0);
  89 }
  90
  91 /** Writes stack backtrace to a string
  92  *
  93  * @param str string
  94  * @param regs A pointer to the struct pt_regs.
  95  * @returns void
  96  */
  97 void _stp_stack_snprint (char *str, int size, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
  98 {
  99         /* To get a string, we use a simple trick. First flush the print buffer, */
 100         /* then call _stp_stack_print, then copy the result into the output string  */
 101         /* and clear the print buffer. */
 102         _stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
 103         _stp_print_flush();
 104         _stp_stack_print(regs, verbose, pi);
 105         strlcpy(str, pb->buf, size < pb->len ? size : pb->len);
 106         pb->len = 0;
 107 }
 108
 109
 110 /** Prints the user stack backtrace
 111  * @param str string
 112  * @returns Same string as was input with trace info appended,
 113  * @note Currently limited to a depth of two. Works from jprobes and kprobes.
 114  */
 115 #if 0
 116 void _stp_ustack_print (char *str)
 117 {
 118         struct pt_regs *nregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) current->thread_info)) - 1;
 119         _stp_printf ("%p : [user]\n", REG_IP(nregs));
 120         if (REG_SP(nregs))
 121                 _stp_printf ("%p : [user]\n", *(unsigned long *)REG_SP(nregs));
 122 }
 123 #endif /* 0 */
 124
 125 /** @} */
 126 #endif /* _STACK_C_ */