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