dt_regset.c revision 297129 
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
42dt_regset_t *
43dt_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
63void
64dt_regset_destroy(dt_regset_t *drp)
65{
66	free(drp->dr_bitmap);
67	free(drp);
68}
69
70void
71dt_regset_reset(dt_regset_t *drp)
72{
73	bzero(drp->dr_bitmap, sizeof (ulong_t) * BT_BITOUL(drp->dr_size));
74}
75
76void
77dt_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
95int
96dt_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
127void
128dt_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