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  */
31 
32 #include <sys/types.h>
33 #include <sys/bitmap.h>
34 #include <assert.h>
35 #include <strings.h>
36 #include <stdlib.h>
37 
38 #include <dt_regset.h>
39 #include <dt_impl.h>
40 
41 dt_regset_t *
dt_regset_create(ulong_t nregs)42 dt_regset_create(ulong_t nregs)
43 {
44 	ulong_t n = BT_BITOUL(nregs);
45 	dt_regset_t *drp = malloc(sizeof (dt_regset_t));
46 
47 	if (drp == NULL)
48 		return (NULL);
49 
50 	drp->dr_bitmap = malloc(sizeof (ulong_t) * n);
51 	drp->dr_size = nregs;
52 
53 	if (drp->dr_bitmap == NULL) {
54 		dt_regset_destroy(drp);
55 		return (NULL);
56 	}
57 
58 	bzero(drp->dr_bitmap, sizeof (ulong_t) * n);
59 	return (drp);
60 }
61 
62 void
dt_regset_destroy(dt_regset_t * drp)63 dt_regset_destroy(dt_regset_t *drp)
64 {
65 	free(drp->dr_bitmap);
66 	free(drp);
67 }
68 
69 void
dt_regset_reset(dt_regset_t * drp)70 dt_regset_reset(dt_regset_t *drp)
71 {
72 	bzero(drp->dr_bitmap, sizeof (ulong_t) * BT_BITOUL(drp->dr_size));
73 }
74 
75 void
dt_regset_assert_free(dt_regset_t * drp)76 dt_regset_assert_free(dt_regset_t *drp)
77 {
78 	int reg;
79 	boolean_t fail = B_FALSE;
80 	for (reg = 0; reg < drp->dr_size; reg++) {
81 		if (BT_TEST(drp->dr_bitmap, reg) != 0)  {
82 			dt_dprintf("%%r%d was left allocated\n", reg);
83 			fail = B_TRUE;
84 		}
85 	}
86 
87 	/*
88 	 * We set this during dtest runs to check for register leaks.
89 	 */
90 	if (fail && getenv("DTRACE_DEBUG_REGSET") != NULL)
91 		abort();
92 }
93 
94 int
dt_regset_alloc(dt_regset_t * drp)95 dt_regset_alloc(dt_regset_t *drp)
96 {
97 	ulong_t nbits = drp->dr_size - 1;
98 	ulong_t maxw = nbits >> BT_ULSHIFT;
99 	ulong_t wx;
100 
101 	for (wx = 0; wx <= maxw; wx++) {
102 		if (drp->dr_bitmap[wx] != ~0UL)
103 			break;
104 	}
105 
106 	if (wx <= maxw) {
107 		ulong_t maxb = (wx == maxw) ? nbits & BT_ULMASK : BT_NBIPUL - 1;
108 		ulong_t word = drp->dr_bitmap[wx];
109 		ulong_t bit, bx;
110 		int reg;
111 
112 		for (bit = 1, bx = 0; bx <= maxb; bx++, bit <<= 1) {
113 			if ((word & bit) == 0) {
114 				reg = (int)((wx << BT_ULSHIFT) | bx);
115 				BT_SET(drp->dr_bitmap, reg);
116 				return (reg);
117 			}
118 		}
119 	}
120 
121 	xyerror(D_NOREG, "Insufficient registers to generate code");
122 	/*NOTREACHED*/
123 	return (-1);
124 }
125 
126 void
dt_regset_free(dt_regset_t * drp,int reg)127 dt_regset_free(dt_regset_t *drp, int reg)
128 {
129 	assert(reg >= 0 && reg < drp->dr_size);
130 	assert(BT_TEST(drp->dr_bitmap, reg) != 0);
131 	BT_CLEAR(drp->dr_bitmap, reg);
132 }
133