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 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <sys/stropts.h> 30 #include <sys/isa_defs.h> 31 #include <sys/nvpair.h> 32 #include <sys/sysmacros.h> 33 #if defined(_KERNEL) && !defined(_BOOT) 34 #include <sys/varargs.h> 35 #else 36 #include <stdarg.h> 37 #include <strings.h> 38 #endif 39 40 /* 41 * This allocator is very simple. 42 * - it uses a pre-allocated buffer for memory allocations. 43 * - it does _not_ free memory in the pre-allocated buffer. 44 * 45 * The reason for the selected implemention is simplicity. 46 * This allocator is designed for the usage in interrupt context when 47 * the caller may not wait for free memory. 48 */ 49 50 /* pre-allocated buffer for memory allocations */ 51 typedef struct nvbuf { 52 uintptr_t nvb_buf; /* address of pre-allocated buffer */ 53 uintptr_t nvb_lim; /* limit address in the buffer */ 54 uintptr_t nvb_cur; /* current address in the buffer */ 55 } nvbuf_t; 56 57 /* 58 * Initialize the pre-allocated buffer allocator. The caller needs to supply 59 * 60 * buf address of pre-allocated buffer 61 * bufsz size of pre-allocated buffer 62 * 63 * nv_fixed_init() calculates the remaining members of nvbuf_t. 64 */ 65 static int 66 nv_fixed_init(nv_alloc_t *nva, va_list valist) 67 { 68 uintptr_t base = va_arg(valist, uintptr_t); 69 uintptr_t lim = base + va_arg(valist, size_t); 70 nvbuf_t *nvb = (nvbuf_t *)P2ROUNDUP(base, sizeof (uintptr_t)); 71 72 if (base == NULL || (uintptr_t)&nvb[1] > lim) 73 return (EINVAL); 74 75 nvb->nvb_buf = (uintptr_t)&nvb[0]; 76 nvb->nvb_cur = (uintptr_t)&nvb[1]; 77 nvb->nvb_lim = lim; 78 nva->nva_arg = nvb; 79 80 return (0); 81 } 82 83 static void * 84 nv_fixed_alloc(nv_alloc_t *nva, size_t size) 85 { 86 nvbuf_t *nvb = nva->nva_arg; 87 uintptr_t new = nvb->nvb_cur; 88 89 if (size == 0 || new + size > nvb->nvb_lim) 90 return (NULL); 91 92 nvb->nvb_cur = P2ROUNDUP(new + size, sizeof (uintptr_t)); 93 94 return ((void *)new); 95 } 96 97 /*ARGSUSED*/ 98 static void 99 nv_fixed_free(nv_alloc_t *nva, void *buf, size_t size) 100 { 101 /* don't free memory in the pre-allocated buffer */ 102 } 103 104 static void 105 nv_fixed_reset(nv_alloc_t *nva) 106 { 107 nvbuf_t *nvb = nva->nva_arg; 108 109 nvb->nvb_cur = (uintptr_t)&nvb[1]; 110 } 111 112 const nv_alloc_ops_t nv_fixed_ops_def = { 113 nv_fixed_init, /* nv_ao_init() */ 114 NULL, /* nv_ao_fini() */ 115 nv_fixed_alloc, /* nv_ao_alloc() */ 116 nv_fixed_free, /* nv_ao_free() */ 117 nv_fixed_reset /* nv_ao_reset() */ 118 }; 119 120 const nv_alloc_ops_t *nv_fixed_ops = &nv_fixed_ops_def; 121