1*2d65afd2Sjoerg /* $NetBSD: elf_support.h,v 1.1 2018/03/29 13:23:39 joerg Exp $ */
2*2d65afd2Sjoerg
3*2d65afd2Sjoerg /*-
4*2d65afd2Sjoerg * Copyright (c) 2018 The NetBSD Foundation, Inc.
5*2d65afd2Sjoerg * All rights reserved.
6*2d65afd2Sjoerg *
7*2d65afd2Sjoerg * Redistribution and use in source and binary forms, with or without
8*2d65afd2Sjoerg * modification, are permitted provided that the following conditions
9*2d65afd2Sjoerg * are met:
10*2d65afd2Sjoerg * 1. Redistributions of source code must retain the above copyright
11*2d65afd2Sjoerg * notice, this list of conditions and the following disclaimer.
12*2d65afd2Sjoerg * 2. Redistributions in binary form must reproduce the above copyright
13*2d65afd2Sjoerg * notice, this list of conditions and the following disclaimer in the
14*2d65afd2Sjoerg * documentation and/or other materials provided with the distribution.
15*2d65afd2Sjoerg *
16*2d65afd2Sjoerg * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17*2d65afd2Sjoerg * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18*2d65afd2Sjoerg * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19*2d65afd2Sjoerg * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20*2d65afd2Sjoerg * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21*2d65afd2Sjoerg * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22*2d65afd2Sjoerg * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23*2d65afd2Sjoerg * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24*2d65afd2Sjoerg * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25*2d65afd2Sjoerg * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26*2d65afd2Sjoerg * POSSIBILITY OF SUCH DAMAGE.
27*2d65afd2Sjoerg */
28*2d65afd2Sjoerg #ifndef _SPARC_ELF_SUPPORT_H
29*2d65afd2Sjoerg #define _SPARC_ELF_SUPPORT_H
30*2d65afd2Sjoerg
31*2d65afd2Sjoerg static inline void
sparc_write_branch(void * where_,void * target)32*2d65afd2Sjoerg sparc_write_branch(void *where_, void *target)
33*2d65afd2Sjoerg {
34*2d65afd2Sjoerg const unsigned int BAA = 0x30800000U; /* ba,a (offset / 4) */
35*2d65afd2Sjoerg const unsigned int SETHI = 0x03000000U; /* sethi %hi(0), %g1 */
36*2d65afd2Sjoerg const unsigned int JMP = 0x81c06000U; /* jmpl %g1+%lo(0), %g0 */
37*2d65afd2Sjoerg
38*2d65afd2Sjoerg unsigned int *where = (unsigned int *)where_;
39*2d65afd2Sjoerg unsigned long value = (unsigned long)target;
40*2d65afd2Sjoerg unsigned long offset = value - (unsigned long)where;
41*2d65afd2Sjoerg
42*2d65afd2Sjoerg #define HIVAL(v, s) (((v) >> (s)) & 0x003fffffU)
43*2d65afd2Sjoerg #define LOVAL(v, s) (((v) >> (s)) & 0x000003ffU)
44*2d65afd2Sjoerg if (offset + 0x800000 <= 0x7ffffc) {
45*2d65afd2Sjoerg /* Displacement is within 8MB, use a direct branch. */
46*2d65afd2Sjoerg where[0] = BAA | ((offset >> 2) & 0x3fffff);
47*2d65afd2Sjoerg __asm volatile("iflush %0+0" : : "r" (where));
48*2d65afd2Sjoerg return;
49*2d65afd2Sjoerg }
50*2d65afd2Sjoerg
51*2d65afd2Sjoerg /*
52*2d65afd2Sjoerg * The absolute address is a 32bit value.
53*2d65afd2Sjoerg * This can be encoded as:
54*2d65afd2Sjoerg * sethi %hi(value), %g1
55*2d65afd2Sjoerg * jmp %g1+%lo(value)
56*2d65afd2Sjoerg */
57*2d65afd2Sjoerg where[1] = JMP | LOVAL(value, 0);
58*2d65afd2Sjoerg __asm volatile("iflush %0+4" : : "r" (where));
59*2d65afd2Sjoerg where[0] = SETHI | HIVAL(value, 10);
60*2d65afd2Sjoerg __asm volatile("iflush %0+0" : : "r" (where));
61*2d65afd2Sjoerg #undef HIVAL
62*2d65afd2Sjoerg #undef LOVAL
63*2d65afd2Sjoerg }
64*2d65afd2Sjoerg #endif
65