source: trunk/kernel/mm/page.h @ 408

Last change on this file since 408 was 408, checked in by alain, 4 years ago

Fix several bugs in the fork() syscall.

File size: 9.1 KB
Line 
1/*
2 * page.h - physical page descriptor and related operations
3 *
4 * Authors Ghassan Almalles (2008,2009,2010,2011,2012)
5 *         Alain Greiner    (2016)
6 *
7 * Copyright (c) UPMC Sorbonne Universites
8 *
9 * This file is part of ALMOS-MKH.
10 *
11 * ALMOS-MKH is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; version 2.0 of the License.
14 *
15 * ALMOS-MKH is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
22 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#ifndef _PAGE_H_
26#define _PAGE_H_
27
28#include <kernel_config.h>
29#include <hal_types.h>
30#include <spinlock.h>
31#include <list.h>
32#include <slist.h>
33#include <xlist.h>
34
35/***   Forward declarations   ***/
36
37struct mapper_s;
38
39/*************************************************************************************
40 * This  defines the flags that can be attached to a physical page.
41 ************************************************************************************/
42
43#define PG_INIT             0x0001     // page descriptor has been initialised
44#define PG_RESERVED         0x0002     // cannot be allocated by PPM
45#define PG_FREE             0x0004     // page can be allocated by PPM
46#define PG_INLOAD           0x0008     // on-going load from disk
47#define PG_IO_ERR           0x0010     // mapper signals a read/write access error
48#define PG_BUFFER           0x0020     // used in blockio.c
49#define PG_DIRTY            0x0040     // page has been written
50#define PG_LOCKED       0x0080     // page is locked
51#define PG_COW          0x0100     // page is copy-on-write
52
53#define PG_ALL          0xFFFF     // All flags
54
55/*************************************************************************************
56 * This structure defines a physical page descriptor.
57 * Size is 64 bytes for a 32 bits core...
58 ************************************************************************************/
59
60typedef struct page_s
61{
62    uint32_t          flags;          /*! flags defined above                  (4)  */
63    uint32_t          order;          /*! log2( number of small pages)         (4)  */
64    struct mapper_s * mapper;         /*! local pointer on associated mapper   (4)  */
65    uint32_t          index;          /*! page index in mapper                 (4)  */
66        list_entry_t      list;           /*! for both dirty pages and free pages  (8)  */
67    xlist_entry_t     wait_root;      /*! root of list of waiting threads      (16) */
68        uint32_t          refcount;       /*! reference counter                    (4)  */
69        uint32_t          fork_nr;        /*! number of pending forks              (4)  */
70        spinlock_t        lock;           /*! only used to set the PG_LOCKED flag  (16) */
71}
72page_t;
73
74/*************************************************************************************
75 * This function initializes one page descriptor.
76 *************************************************************************************
77 * @ page    : pointer to page descriptor
78 ************************************************************************************/
79inline void page_init( page_t * page );
80
81/*************************************************************************************
82 * This function atomically set one or several flags in page descriptor flags.
83 *************************************************************************************
84 * @ page    : pointer to page descriptor.
85 * @ value   : all non zero bits in value will be set.
86 ************************************************************************************/
87inline void page_set_flag( page_t   * page,
88                           uint32_t   value );
89
90/*************************************************************************************
91 * This function atomically reset one or several flags in page descriptor flags.
92 *************************************************************************************
93 * @ page    : pointer to page descriptor.
94 * @ value   : all non zero bits in value will be cleared.
95 ************************************************************************************/
96inline void page_clear_flag( page_t   * page,
97                             uint32_t   value );
98
99/*************************************************************************************
100 * This function tests the value of one or several flags in page descriptor flags.
101 *************************************************************************************
102 * @ page    : pointer to page descriptor.
103 * @ value   : all non zero bits will be tested.
104 * @ returns true if at least one non zero bit in value is set / false otherwise.
105 ************************************************************************************/
106inline bool_t page_is_flag( page_t   * page,
107                            uint32_t   value );
108
109/*************************************************************************************
110 * This function synchronizes (i.e. update the disk) all dirty pages in a cluster.
111 * It scans the PPM dirty list, that should be empty when this operation is completed.
112 ************************************************************************************/
113void sync_all_pages();
114
115/*************************************************************************************
116 * This function sets the PG_DIRTY flag in the page descriptor,
117 * and registers the page in the dirty list in PPM.
118 *************************************************************************************
119 * @ page     : pointer on page descriptor.
120 * @ returns true if page was not dirty / returns false if page was dirty
121 ************************************************************************************/
122bool_t page_do_dirty( page_t * page );
123
124/*************************************************************************************
125 * This function resets the PG_DIRTY flag in the page descriptor,
126 * and removes the page from the dirty list in PPM.
127 *************************************************************************************
128 * @ page     : pointer on page descriptor.
129 * @ returns true if page was dirty / returns false if page was not dirty
130 ************************************************************************************/
131bool_t page_undo_dirty( page_t * page );
132
133/*************************************************************************************
134 * This function resets to 0 all bytes in a given page.
135 *************************************************************************************
136 * @ page     : pointer on page descriptor.
137 ************************************************************************************/
138void page_zero( page_t * page );
139
140/*************************************************************************************
141 * This blocking function set the PG_LOCKED flag on the page.
142 * It deschedule if the page has already been locked by another thread,
143 * and returns only when the flag has been successfully set.
144 *************************************************************************************
145 * @ page     : pointer on page descriptor.
146 ************************************************************************************/
147void page_lock( page_t * page );
148
149/*************************************************************************************
150 * This blocking function resets the PG_LOCKED flag on the page, if there is no
151 * other waiting thread. If there is waiting thread(s), it activates the first
152 * waiting thread without modifying the PG_LOCKED flag.
153 *************************************************************************************
154 * @ page     : pointer on page descriptor.
155 ************************************************************************************/
156void page_unlock( page_t * page );
157
158/*************************************************************************************
159 * This blocking function atomically increments the page refcount.
160 *************************************************************************************
161 * @ page     : pointer on page descriptor.
162 ************************************************************************************/
163inline void page_refcount_up( page_t * page );
164
165/*************************************************************************************
166 * This blocking function atomically decrements the page refcount.
167 *************************************************************************************
168 * @ page     : pointer on page descriptor.
169 ************************************************************************************/
170inline void page_refcount_down( page_t * page );
171
172/*************************************************************************************
173 * This function display the values contained in a page descriptor.
174 *************************************************************************************
175 * @ page     : pointer on page descriptor.
176 ************************************************************************************/
177void page_print( page_t * page );
178
179
180#endif  /* _PAGE_H_ */
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