1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
/*
* Copyright (c) 2006 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/mman.h>
#include <stdio.h>
#include <string.h>
/* Supported long branch types */
#define Call 1
#define Cond 2
/* Supported predicates */
#define False 1
#define True 2
/* Supported variations */
#define Backward 1
#define Forward 2
#if TYPE == 0 || PRED == 0 || VAR == 0
#error Define TYPE, PRED and/or VAR
#endif
union bundle {
unsigned char bytes[16];
long double _align;
};
/*
* Machine code of a bundle containing a long branch. The predicate of the
* long branch is the result of the compare in the first slot.
* The assembly of the bundle is:
* { .mlx
* cmp.eq p0,p15= <PREDICATE>,r0
* (p15) brl.few <TARGET> ;;
* }
* the predicate is written to bit 18:1
* The branch target is written to bits 100:20, 48:39 and 123:1
*/
unsigned char mc_brl_cond[16] = {
0x05, 0x00, 0x00, 0x00, 0x0f, 0x39,
0x00, 0x00, 0x00, 0x00, 0x80, 0x07,
0x00, 0x00, 0x00, 0xc0
};
/*
* Machine code of the epilogue of a typical function returning an integer.
* The assembly of the epilogue is:
* { .mib
* nop.m 0
* addl r8 = <RETVAL>, r0
* br.ret.sptk.few b0 ;;
* }
* The return value is written to bits 59:7, 73:9, 68:5, and 82:1.
*/
unsigned char mc_epilogue[16] = {
0x11, 0x00, 0x00, 0x00, 0x01, 0x00,
0x80, 0x00, 0x00, 0x00, 0x48, 0x80,
0x00, 0x00, 0x84, 0x00
};
void
mc_patch(union bundle *b, unsigned long val, int start, int len)
{
unsigned long mask;
int bit, byte, run;
byte = start >> 3;
bit = start & 7;
while (len) {
run = ((len > (8 - bit)) ? (8 - bit) : len);
mask = (1UL << run) - 1UL;
b->bytes[byte] |= (val & mask) << bit;
val >>= run;
len -= run;
byte++;
bit = 0;
}
}
void
assemble_brl_cond(union bundle *b, int pred, unsigned long tgt)
{
unsigned long iprel;
iprel = tgt - (unsigned long)b;
memcpy(b->bytes, mc_brl_cond, sizeof(mc_brl_cond));
mc_patch(b, pred ? 1 : 0, 18, 1);
mc_patch(b, iprel >> 4, 100, 20);
mc_patch(b, iprel >> 24, 48, 39);
mc_patch(b, iprel >> 63, 123, 1);
}
void
assemble_epilogue(union bundle *b, int retval)
{
memcpy(b->bytes, mc_epilogue, sizeof(mc_epilogue));
mc_patch(b, retval, 59, 7);
mc_patch(b, retval >> 7, 73, 9);
mc_patch(b, retval >> 16, 68, 5);
mc_patch(b, retval >> 21, 82, 1);
}
int
doit(void *addr)
{
asm("mov b6 = %0; br.sptk b6;;" :: "r"(addr));
return 1;
}
int
test_cond(int pred, union bundle *src, union bundle *dst)
{
assemble_epilogue(dst, pred ? 0 : 2);
assemble_brl_cond(src, pred ? 1 : 0, (unsigned long)dst);
assemble_epilogue(src + 1, !pred ? 0 : 2);
return doit(src);
}
int
main()
{
static union bundle blob_low[2];
union bundle *blob_high;
void *addr;
addr = (void *)0x7FFFFFFF00000000L;
blob_high = mmap(addr, 32, PROT_EXEC | PROT_READ | PROT_WRITE,
MAP_ANON, -1, 0L);
if (blob_high != addr)
printf("NOTICE: blob_high is at %p, not at %p\n", blob_high,
addr);
#if TYPE == Call
return (test_call(blob_high, blob_low));
#elif TYPE == Cond
#if VAR == Forward
return (test_cond(PRED - 1, blob_low, blob_high));
#elif VAR == Backward
return (test_cond(PRED - 1, blob_high, blob_low));
#else
return (1);
#endif
#else
return (1);
#endif
}
|
