xref: /freebsd/cddl/contrib/opensolaris/lib/libdtrace/common/dt_regset.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 
23 /*
24  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
25  * Use is subject to license terms.
26  */
27 
28 /*
29  * Copyright (c) 2012 by Delphix. All rights reserved.
30  * Copyright (c) 2016 Pedro Giffuni.  All rights reserved.
31  */
32 
33 #include <sys/types.h>
34 #include <sys/bitmap.h>
35 #include <assert.h>
36 #include <strings.h>
37 #include <stdlib.h>
38 
39 #include <dt_regset.h>
40 #include <dt_impl.h>
41 
42 dt_regset_t *
43 dt_regset_create(ulong_t nregs)
44 {
45 	ulong_t n = BT_BITOUL(nregs);
46 	dt_regset_t *drp = malloc(sizeof (dt_regset_t));
47 
48 	if (drp == NULL)
49 		return (NULL);
50 
51 	drp->dr_bitmap = calloc(n, sizeof (ulong_t));
52 
53 	if (drp->dr_bitmap == NULL) {
54 		dt_regset_destroy(drp);
55 		return (NULL);
56 	}
57 
58 	drp->dr_size = nregs;
59 
60 	return (drp);
61 }
62 
63 void
64 dt_regset_destroy(dt_regset_t *drp)
65 {
66 	free(drp->dr_bitmap);
67 	free(drp);
68 }
69 
70 void
71 dt_regset_reset(dt_regset_t *drp)
72 {
73 	bzero(drp->dr_bitmap, sizeof (ulong_t) * BT_BITOUL(drp->dr_size));
74 }
75 
76 void
77 dt_regset_assert_free(dt_regset_t *drp)
78 {
79 	int reg;
80 	boolean_t fail = B_FALSE;
81 	for (reg = 0; reg < drp->dr_size; reg++) {
82 		if (BT_TEST(drp->dr_bitmap, reg) != 0)  {
83 			dt_dprintf("%%r%d was left allocated\n", reg);
84 			fail = B_TRUE;
85 		}
86 	}
87 
88 	/*
89 	 * We set this during dtest runs to check for register leaks.
90 	 */
91 	if (fail && getenv("DTRACE_DEBUG_REGSET") != NULL)
92 		abort();
93 }
94 
95 int
96 dt_regset_alloc(dt_regset_t *drp)
97 {
98 	ulong_t nbits = drp->dr_size - 1;
99 	ulong_t maxw = nbits >> BT_ULSHIFT;
100 	ulong_t wx;
101 
102 	for (wx = 0; wx <= maxw; wx++) {
103 		if (drp->dr_bitmap[wx] != ~0UL)
104 			break;
105 	}
106 
107 	if (wx <= maxw) {
108 		ulong_t maxb = (wx == maxw) ? nbits & BT_ULMASK : BT_NBIPUL - 1;
109 		ulong_t word = drp->dr_bitmap[wx];
110 		ulong_t bit, bx;
111 		int reg;
112 
113 		for (bit = 1, bx = 0; bx <= maxb; bx++, bit <<= 1) {
114 			if ((word & bit) == 0) {
115 				reg = (int)((wx << BT_ULSHIFT) | bx);
116 				BT_SET(drp->dr_bitmap, reg);
117 				return (reg);
118 			}
119 		}
120 	}
121 
122 	xyerror(D_NOREG, "Insufficient registers to generate code");
123 	/*NOTREACHED*/
124 	return (-1);
125 }
126 
127 void
128 dt_regset_free(dt_regset_t *drp, int reg)
129 {
130 	assert(reg >= 0 && reg < drp->dr_size);
131 	assert(BT_TEST(drp->dr_bitmap, reg) != 0);
132 	BT_CLEAR(drp->dr_bitmap, reg);
133 }
134