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 (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or https://opensource.org/licenses/CDDL-1.0. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #include <sys/isa_defs.h> 28 #include <sys/nvpair.h> 29 #include <sys/sysmacros.h> 30 31 /* 32 * This allocator is very simple. 33 * - it uses a pre-allocated buffer for memory allocations. 34 * - it does _not_ free memory in the pre-allocated buffer. 35 * 36 * The reason for the selected implementation is simplicity. 37 * This allocator is designed for the usage in interrupt context when 38 * the caller may not wait for free memory. 39 */ 40 41 /* pre-allocated buffer for memory allocations */ 42 typedef struct nvbuf { 43 uintptr_t nvb_buf; /* address of pre-allocated buffer */ 44 uintptr_t nvb_lim; /* limit address in the buffer */ 45 uintptr_t nvb_cur; /* current address in the buffer */ 46 } nvbuf_t; 47 48 /* 49 * Initialize the pre-allocated buffer allocator. The caller needs to supply 50 * 51 * buf address of pre-allocated buffer 52 * bufsz size of pre-allocated buffer 53 * 54 * nv_fixed_init() calculates the remaining members of nvbuf_t. 55 */ 56 static int 57 nv_fixed_init(nv_alloc_t *nva, va_list valist) 58 { 59 uintptr_t base = va_arg(valist, uintptr_t); 60 uintptr_t lim = base + va_arg(valist, size_t); 61 nvbuf_t *nvb = (nvbuf_t *)P2ROUNDUP(base, sizeof (uintptr_t)); 62 63 if (base == 0 || (uintptr_t)&nvb[1] > lim) 64 return (EINVAL); 65 66 nvb->nvb_buf = (uintptr_t)&nvb[0]; 67 nvb->nvb_cur = (uintptr_t)&nvb[1]; 68 nvb->nvb_lim = lim; 69 nva->nva_arg = nvb; 70 71 return (0); 72 } 73 74 static void * 75 nv_fixed_alloc(nv_alloc_t *nva, size_t size) 76 { 77 nvbuf_t *nvb = nva->nva_arg; 78 uintptr_t new = nvb->nvb_cur; 79 80 if (size == 0 || new + size > nvb->nvb_lim) 81 return (NULL); 82 83 nvb->nvb_cur = P2ROUNDUP(new + size, sizeof (uintptr_t)); 84 85 return ((void *)new); 86 } 87 88 static void 89 nv_fixed_free(nv_alloc_t *nva, void *buf, size_t size) 90 { 91 /* don't free memory in the pre-allocated buffer */ 92 (void) nva, (void) buf, (void) size; 93 } 94 95 static void 96 nv_fixed_reset(nv_alloc_t *nva) 97 { 98 nvbuf_t *nvb = nva->nva_arg; 99 100 nvb->nvb_cur = (uintptr_t)&nvb[1]; 101 } 102 103 static const nv_alloc_ops_t nv_fixed_ops_def = { 104 .nv_ao_init = nv_fixed_init, 105 .nv_ao_fini = NULL, 106 .nv_ao_alloc = nv_fixed_alloc, 107 .nv_ao_free = nv_fixed_free, 108 .nv_ao_reset = nv_fixed_reset 109 }; 110 111 const nv_alloc_ops_t *const nv_fixed_ops = &nv_fixed_ops_def; 112 113 #if defined(_KERNEL) 114 EXPORT_SYMBOL(nv_fixed_ops); 115 #endif 116