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
41dt_regset_t *
42dt_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
62void
63dt_regset_destroy(dt_regset_t *drp)
64{
65	free(drp->dr_bitmap);
66	free(drp);
67}
68
69void
70dt_regset_reset(dt_regset_t *drp)
71{
72	bzero(drp->dr_bitmap, sizeof (ulong_t) * BT_BITOUL(drp->dr_size));
73}
74
75void
76dt_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
94int
95dt_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
126void
127dt_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