116 lines
3 KiB
C
116 lines
3 KiB
C
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/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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#include <sys/isa_defs.h>
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#include <sys/nvpair.h>
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#include <sys/sysmacros.h>
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/*
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* This allocator is very simple.
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* - it uses a pre-allocated buffer for memory allocations.
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* - it does _not_ free memory in the pre-allocated buffer.
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*
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* The reason for the selected implementation is simplicity.
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* This allocator is designed for the usage in interrupt context when
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* the caller may not wait for free memory.
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*/
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/* pre-allocated buffer for memory allocations */
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typedef struct nvbuf {
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uintptr_t nvb_buf; /* address of pre-allocated buffer */
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uintptr_t nvb_lim; /* limit address in the buffer */
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uintptr_t nvb_cur; /* current address in the buffer */
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} nvbuf_t;
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/*
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* Initialize the pre-allocated buffer allocator. The caller needs to supply
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*
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* buf address of pre-allocated buffer
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* bufsz size of pre-allocated buffer
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*
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* nv_fixed_init() calculates the remaining members of nvbuf_t.
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*/
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static int
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nv_fixed_init(nv_alloc_t *nva, va_list valist)
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{
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uintptr_t base = va_arg(valist, uintptr_t);
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uintptr_t lim = base + va_arg(valist, size_t);
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nvbuf_t *nvb = (nvbuf_t *)P2ROUNDUP(base, sizeof (uintptr_t));
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if (base == 0 || (uintptr_t)&nvb[1] > lim)
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return (EINVAL);
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nvb->nvb_buf = (uintptr_t)&nvb[0];
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nvb->nvb_cur = (uintptr_t)&nvb[1];
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nvb->nvb_lim = lim;
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nva->nva_arg = nvb;
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return (0);
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}
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static void *
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nv_fixed_alloc(nv_alloc_t *nva, size_t size)
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{
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nvbuf_t *nvb = nva->nva_arg;
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uintptr_t new = nvb->nvb_cur;
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if (size == 0 || new + size > nvb->nvb_lim)
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return (NULL);
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nvb->nvb_cur = P2ROUNDUP(new + size, sizeof (uintptr_t));
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return ((void *)new);
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}
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/*ARGSUSED*/
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static void
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nv_fixed_free(nv_alloc_t *nva, void *buf, size_t size)
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{
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/* don't free memory in the pre-allocated buffer */
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}
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static void
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nv_fixed_reset(nv_alloc_t *nva)
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{
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nvbuf_t *nvb = nva->nva_arg;
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nvb->nvb_cur = (uintptr_t)&nvb[1];
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}
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const nv_alloc_ops_t nv_fixed_ops_def = {
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.nv_ao_init = nv_fixed_init,
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.nv_ao_fini = NULL,
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.nv_ao_alloc = nv_fixed_alloc,
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.nv_ao_free = nv_fixed_free,
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.nv_ao_reset = nv_fixed_reset
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};
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const nv_alloc_ops_t *nv_fixed_ops = &nv_fixed_ops_def;
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#if defined(_KERNEL)
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EXPORT_SYMBOL(nv_fixed_ops);
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#endif
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