xref: /freebsd/libexec/rtld-elf/amd64/rtld_machdep.h (revision b601c69bdbe8755d26570261d7fd4c02ee4eff74)
1 /*-
2  * Copyright (c) 1999, 2000 John D. Polstra.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #ifndef RTLD_MACHDEP_H
30 #define RTLD_MACHDEP_H	1
31 
32 /* Return the address of the .dynamic section in the dynamic linker. */
33 #define rtld_dynamic(obj) \
34     ((const Elf_Dyn *)((obj)->relocbase + (Elf_Addr)&_DYNAMIC))
35 
36 /* Fixup the jump slot at "where" to transfer control to "target". */
37 #define reloc_jmpslot(where, target)			\
38     do {						\
39 	dbg("reloc_jmpslot: *%p = %p", (void *)(where),	\
40 	  (void *)(target));				\
41 	(*(Elf_Addr *)(where) = (Elf_Addr)(target));	\
42     } while (0)
43 
44 static inline void
45 atomic_decr_int(volatile int *p)
46 {
47     __asm __volatile ("lock; decl %0" : "=m"(*p) : "0"(*p) : "cc");
48 }
49 
50 static inline void
51 atomic_incr_int(volatile int *p)
52 {
53     __asm __volatile ("lock; incl %0" : "=m"(*p) : "0"(*p) : "cc");
54 }
55 
56 static inline void
57 atomic_add_int(volatile int *p, int val)
58 {
59     __asm __volatile ("lock; addl %1, %0"
60 	: "=m"(*p)
61 	: "ri"(val), "0"(*p)
62 	: "cc");
63 }
64 
65 #endif
66