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 http://www.opensolaris.org/os/licensing. 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 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #ifndef _SYS_HOLD_PAGE_H 27 #define _SYS_HOLD_PAGE_H 28 29 #pragma ident "%Z%%M% %I% %E% SMI" 30 31 #ifdef __cplusplus 32 extern "C" { 33 #endif 34 35 #include <sys/types.h> 36 #include <vm/page.h> 37 38 /* 39 * swrand generates entropy by mapping different pages in the system. This 40 * can create problems for some hypervisors, as certain pages may be removed 41 * from the system at any time. The following interfaces allow swrand to 42 * check the validity and make sure a page is not given away while it is mapped. 43 * 44 * int plat_hold_page(pfn_t pfn, int lock, page_t **pp_ret) 45 * 46 * If lock is PLAT_HOLD_NO_LOCK, simply check if the page pfn is valid 47 * in the system. If the page is valid, PLAT_HOLD_OK will be returned. 48 * pp_ret is ignored if lock is PLAT_HOLD_NO_LOCK. 49 * 50 * If lock is PLAT_HOLD_LOCK, in addition to the above, attempt to lock 51 * the page exclusively. Again, if the lock is successful, the page 52 * pointer will be put in pp_ret, and PLAT_HOLD_OK will be returned. 53 * pp_ret must be passed to a later call to plat_release_page. If the 54 * page wasn't found, or the lock couldn't be grabbed, the return value 55 * will be PLAT_HOLD_FAIL. 56 * 57 * void plat_release_page(page_t *pp) 58 * 59 * Unlock the page pp. Should only be called after a previous, 60 * successful call to plat_hold_page(pfn, PLAT_HOLD_LOCK, &pp); 61 */ 62 63 #define PLAT_HOLD_NO_LOCK 0 64 #define PLAT_HOLD_LOCK 1 65 66 #define PLAT_HOLD_OK 0 67 #define PLAT_HOLD_FAIL 1 68 69 extern int plat_hold_page(pfn_t, int, page_t **); 70 extern void plat_release_page(page_t *); 71 72 #ifdef __cplusplus 73 } 74 #endif 75 76 #endif /* _SYS_HOLD_PAGE_H */ 77