1/* $NetBSD: elf_support.h,v 1.1 2018/03/29 13:23:40 joerg Exp $ */
2
3/*-
4 * Copyright (c) 2000 Eduardo Horvath.
5 * Copyright (c) 2018 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29#ifndef _SPARC64_ELF_SUPPORT_H
30#define _SPARC64_ELF_SUPPORT_H
31
32#ifdef __arch64__
33/*
34 * Create a jump to the location `target` starting at `where`.
35 * This requires up to 6 instructions.
36 * The first instruction is written last as it replaces a branch
37 * in the PLT during lazy binding.
38 * The resulting code can trash %g1 and %g5.
39 */
40static inline void
41sparc_write_branch(void *where_, void *target)
42{
43 const unsigned int BAA = 0x30800000U; /* ba,a (offset / 4) */
44 const unsigned int SETHI = 0x03000000U; /* sethi %hi(0), %g1 */
45 const unsigned int JMP = 0x81c06000U; /* jmpl %g1+%lo(0), %g0 */
46 const unsigned int OR = 0x82106000U; /* or %g1, 0, %g1 */
47 const unsigned int XOR = 0x82186000U; /* xor %g1, 0, %g1 */
48 const unsigned int MOV71 = 0x8213e000U; /* or %o7, 0, %g1 */
49 const unsigned int MOV17 = 0x9e106000U; /* or %g1, 0, %o7 */
50 const unsigned int CALL = 0x40000000U; /* call 0 */
51 const unsigned int SLLX = 0x83287000U; /* sllx %g1, 0, %g1 */
52 const unsigned int NEG = 0x82200001U; /* neg %g1 */
53 const unsigned int SETHIG5 = 0x0b000000U; /* sethi %hi(0), %g5 */
54 const unsigned int ORG5 = 0x82104005U; /* or %g1, %g5, %g1 */
55
56 unsigned int *where = (unsigned int *)where_;
57 unsigned long value = (unsigned long)target;
58 unsigned long offset = value - (unsigned long)where;
59
60#define HIVAL(v, s) (((v) >> (s)) & 0x003fffffU)
61#define LOVAL(v, s) (((v) >> (s)) & 0x000003ffU)
62 if (offset + 0x800000 <= 0x7ffffc) {
63 /* Displacement is within 8MB, use a direct branch. */
64 where[0] = BAA | ((offset >> 2) & 0x3fffff);
65 __asm volatile("iflush %0+0" : : "r" (where));
66 return;
67 }
68
69 if (value <= 0xffffffffUL) {
70 /*
71 * The absolute address is a 32bit value.
72 * This can be encoded as:
73 * sethi %hi(value), %g1
74 * jmp %g1+%lo(value)
75 */
76 where[1] = JMP | LOVAL(value, 0);
77 __asm volatile("iflush %0+4" : : "r" (where));
78 where[0] = SETHI | HIVAL(value, 10);
79 __asm volatile("iflush %0+0" : : "r" (where));
80 return;
81 }
82
83 if (value >= 0xffffffff00000000UL) {
84 /*
85 * The top 32bit address range can be encoded as:
86 * sethi %hix(addr), %g1
87 * xor %g1, %lox(addr), %g1
88 * jmp %g1
89 */
90 where[2] = JMP;
91 where[1] = XOR | (value & 0x00003ff) | 0x1c00;
92 __asm volatile("iflush %0+4" : : "r" (where));
93 __asm volatile("iflush %0+8" : : "r" (where));
94 where[0] = SETHI | HIVAL(~value, 10);
95 __asm volatile("iflush %0+0" : : "r" (where));
96 return;
97 }
98
99 if ((offset + 4) + 0x80000000UL <= 0x100000000UL) {
100 /*
101 * Displacement of the second instruction is within
102 * +-2GB. This can use a direct call instruction:
103 * mov %o7, %g1
104 * call (value - .)
105 * mov %g1, %o7
106 */
107 where[1] = CALL | ((-(offset + 4)>> 2) & 0x3fffffffU);
108 where[2] = MOV17;
109 __asm volatile("iflush %0+4" : : "r" (where));
110 __asm volatile("iflush %0+8" : : "r" (where));
111 where[0] = MOV71;
112 __asm volatile("iflush %0+0" : : "r" (where));
113 return;
114 }
115
116 if (value < 0x100000000000UL) {
117 /*
118 * The absolute address is a 44bit value.
119 * This can be encoded as:
120 * sethi %h44(addr), %g1
121 * or %g1, %m44(addr), %g1
122 * sllx %g1, 12, %g1
123 * jmp %g1+%l44(addr)
124 */
125 where[1] = OR | (((value) >> 12) & 0x00001fff);
126 where[2] = SLLX | 12;
127 where[3] = JMP | LOVAL(value, 0);
128 __asm volatile("iflush %0+4" : : "r" (where));
129 __asm volatile("iflush %0+8" : : "r" (where));
130 __asm volatile("iflush %0+12" : : "r" (where));
131 where[0] = SETHI | HIVAL(value, 22);
132 __asm volatile("iflush %0+0" : : "r" (where));
133 return;
134 }
135
136 if (value > 0xfffff00000000000UL) {
137 /*
138 * The top 44bit address range can be encoded as:
139 * sethi %hi((-addr)>>12), %g1
140 * or %g1, %lo((-addr)>>12), %g1
141 * neg %g1
142 * sllx %g1, 12, %g1
143 * jmp %g1+(addr&0x0fff)
144 */
145 unsigned long neg = (-value)>>12;
146 where[1] = OR | (LOVAL(neg, 0)+1);
147 where[2] = NEG;
148 where[3] = SLLX | 12;
149 where[4] = JMP | (value & 0x0fff);
150 __asm volatile("iflush %0+4" : : "r" (where));
151 __asm volatile("iflush %0+8" : : "r" (where));
152 __asm volatile("iflush %0+12" : : "r" (where));
153 __asm volatile("iflush %0+16" : : "r" (where));
154 where[0] = SETHI | HIVAL(neg, 10);
155 __asm volatile("iflush %0+0" : : "r" (where));
156 return;
157 }
158
159 /*
160 * The general case of a 64bit address is encoded as:
161 * sethi %hh(addr), %g1
162 * sethi %lm(addr), %g5
163 * or %g1, %hm(addr), %g1
164 * sllx %g1, 32, %g1
165 * or %g1, %g5, %g1
166 * jmp %g1+%lo(addr)
167 */
168 where[1] = SETHIG5 | HIVAL(value, 10);
169 where[2] = OR | LOVAL(value, 32);
170 where[3] = SLLX | 32;
171 where[4] = ORG5;
172 where[5] = JMP | LOVAL(value, 0);
173 __asm volatile("iflush %0+4" : : "r" (where));
174 __asm volatile("iflush %0+8" : : "r" (where));
175 __asm volatile("iflush %0+12" : : "r" (where));
176 __asm volatile("iflush %0+16" : : "r" (where));
177 __asm volatile("iflush %0+20" : : "r" (where));
178 where[0] = SETHI | HIVAL(value, 42);
179 __asm volatile("iflush %0+0" : : "r" (where));
180#undef HIVAL
181#undef LOVAL
182}
183#else
184#include <sparc/elf_support.h>
185#endif
186#endif