VirtualBox

source: vbox/trunk/src/VBox/Runtime/r3/posix/system-page-size-posix.cpp@ 103795

Last change on this file since 103795 was 100307, checked in by vboxsync, 17 months ago

Runtime,Additions,HostDrivers: Provide API to query the host page size and associated parameters for architectures where the used page size can vary (like on linux.arm64 depending on the kernel config), bugref:10476

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1/* $Id: system-page-size-posix.cpp 100307 2023-06-28 10:17:34Z vboxsync $ */
2/** @file
3 * IPRT - RTSystemGetPageSize(), RTSystemGetPageShift(), RTSystemGetPageOffsetMask() and RTSystemPageAlignSize(), Posix ring-3.
4 */
5
6/*
7 * Copyright (C) 2023 Oracle and/or its affiliates.
8 *
9 * This file is part of VirtualBox base platform packages, as
10 * available from https://www.virtualbox.org.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation, in version 3 of the
15 * License.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, see <https://www.gnu.org/licenses>.
24 *
25 * The contents of this file may alternatively be used under the terms
26 * of the Common Development and Distribution License Version 1.0
27 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
28 * in the VirtualBox distribution, in which case the provisions of the
29 * CDDL are applicable instead of those of the GPL.
30 *
31 * You may elect to license modified versions of this file under the
32 * terms and conditions of either the GPL or the CDDL or both.
33 *
34 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
35 */
36
37
38/*********************************************************************************************************************************
39* Header Files *
40*********************************************************************************************************************************/
41#include <iprt/system.h>
42#include "internal/iprt.h"
43#include "internal/system.h"
44
45#include <iprt/asm.h>
46#include <iprt/assert.h>
47#include <iprt/errcore.h>
48
49#include <unistd.h>
50#include <errno.h>
51
52
53/*********************************************************************************************************************************
54* Global Variables *
55*********************************************************************************************************************************/
56/** The page size used in bytes. */
57static uint32_t g_cbPage = 0;
58/** The page shift in bits. */
59static uint32_t g_cPageShift = 0;
60/** The page offset mask. */
61static uintptr_t g_fPageOff = 0;
62
63
64DECLHIDDEN(int) rtSystemInitPageSize(void)
65{
66 long cbPage = sysconf(_SC_PAGESIZE);
67 if (cbPage == -1)
68 return RTErrConvertFromErrno(errno);
69
70 /* Some sanity check to fend of bogus values (should not happen). */
71 AssertReturn(cbPage == _4K || cbPage == _16K || cbPage == _64K,
72 VERR_NOT_SUPPORTED);
73
74 g_cbPage = (uint32_t)cbPage;
75 g_fPageOff = (uintptr_t)cbPage - 1;
76 g_cPageShift = ASMBitFirstSet(&g_cbPage, sizeof(uint32_t) * 8);
77 return VINF_SUCCESS;
78}
79
80
81RTDECL(uint32_t) RTSystemGetPageSize(void)
82{
83 Assert(g_cbPage > 0);
84 return g_cbPage;
85}
86
87
88RTDECL(uint32_t) RTSystemGetPageShift(void)
89{
90 Assert(g_cPageShift > 0);
91 return g_cPageShift;
92}
93
94
95RTDECL(uintptr_t) RTSystemGetPageOffsetMask(void)
96{
97 Assert(g_fPageOff > 0);
98 return g_fPageOff;
99}
100
101
102RTDECL(size_t) RTSystemPageAlignSize(size_t cb)
103{
104 Assert(g_cbPage > 0);
105 return RT_ALIGN_Z(cb, g_cbPage);
106}
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