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      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