1 /* Return backtrace of current program state. 64 bit S/390 version.
2 Copyright (C) 2001-2015 Free Software Foundation, Inc.
3 Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
20 #include <bits/libc-lock.h>
28 /* This is a global variable set at program start time. It marks the
29 highest used stack address. */
30 extern void *__libc_stack_end
;
33 /* This is the stack layout we see for every non-leaf function.
35 %r15 -> +------------------+
39 80 | save area r6-r15 | 48
40 16 | save area f4,f6 | 128
43 r14 in the save area holds the return address.
63 static _Unwind_Reason_Code (*unwind_backtrace
) (_Unwind_Trace_Fn
, void *);
64 static _Unwind_Ptr (*unwind_getip
) (struct _Unwind_Context
*);
69 void *handle
= __libc_dlopen ("libgcc_s.so.1");
74 unwind_backtrace
= __libc_dlsym (handle
, "_Unwind_Backtrace");
75 unwind_getip
= __libc_dlsym (handle
, "_Unwind_GetIP");
76 if (unwind_getip
== NULL
)
77 unwind_backtrace
= NULL
;
81 __backchain_backtrace (void **array
, int size
)
83 /* We assume that all the code is generated with frame pointers set. */
87 asm ("LGR %0,%%r15" : "=d" (stack
) );
88 /* We skip the call to this function, it makes no sense to record it. */
89 stack
= (struct layout
*) stack
->back_chain
;
92 if (stack
== NULL
|| (void *) stack
> __libc_stack_end
)
93 /* This means the address is out of range. Note that for the
94 toplevel we see a frame pointer with value NULL which clearly is
98 array
[cnt
++] = (void *) stack
->save_grps
[8];
100 stack
= (struct layout
*) stack
->back_chain
;
106 # define unwind_backtrace _Unwind_Backtrace
107 # define unwind_getip _Unwind_GetIP
110 static _Unwind_Reason_Code
111 backtrace_helper (struct _Unwind_Context
*ctx
, void *a
)
113 struct trace_arg
*arg
= a
;
115 /* We are first called with address in the __backtrace function.
118 arg
->array
[arg
->cnt
] = (void *) unwind_getip (ctx
);
119 if (++arg
->cnt
== arg
->size
)
120 return _URC_END_OF_STACK
;
121 return _URC_NO_REASON
;
125 __backtrace (void **array
, int size
)
127 struct trace_arg arg
= { .array
= array
, .size
= size
, .cnt
= -1 };
133 __libc_once_define (static, once
);
135 __libc_once (once
, init
);
137 if (unwind_backtrace
== NULL
)
138 return __backchain_backtrace (array
, size
);
141 unwind_backtrace (backtrace_helper
, &arg
);
143 return arg
.cnt
!= -1 ? arg
.cnt
: 0;
146 weak_alias (__backtrace
, backtrace
)
147 libc_hidden_def (__backtrace
)