source: trunk/kernel/mm/page.h @ 621

Last change on this file since 621 was 612, checked in by alain, 6 years ago

Fix several bugs in vfs.c, fatfs.c, and devfs.c to support
the <.> and <..> directory entries.
File size: 6.5 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_kernel_types.h>
30#include <remote_busylock.h>
31#include <list.h>
32
33/***   Forward declarations   ***/
34
35struct mapper_s;
36
37/*************************************************************************************
38 * This  defines the flags that can be attached to a physical page.
39 ************************************************************************************/
40
41#define PG_INIT             0x0001     // page descriptor has been initialised
42#define PG_RESERVED         0x0002     // cannot be allocated by PPM
43#define PG_FREE             0x0004     // page can be allocated by PPM
44#define PG_DIRTY            0x0040     // page has been written
45#define PG_COW          0x0080     // page is copy-on-write
46
47/*************************************************************************************
48 * This structure defines a physical page descriptor.
49 * - The remote_busylock is used to allows any remote thread to atomically
50 *   test/modify the forks counter or the page flags.
51 * - The list entry is used to register the page in a free list or in dirty list.
52 * NOTE: Size is 48 bytes for a 32 bits core.
53 * TODO : the refcount use is not defined [AG]
54 ************************************************************************************/
55
56typedef struct page_s
57{
58    uint32_t          flags;          /*! flags defined above                  (4)  */
59    uint32_t          order;          /*! log2( number of small pages)         (4)  */
60    struct mapper_s * mapper;         /*! local pointer on associated mapper   (4)  */
61    uint32_t          index;          /*! page index in mapper                 (4)  */
62        list_entry_t      list;           /*! for both dirty pages and free pages  (8)  */
63        uint32_t          refcount;       /*! reference counter TODO ??? [AG]      (4)  */
64        uint32_t          forks;          /*! number of pending forks              (4)  */
65        remote_busylock_t lock;           /*! protect forks or flags modifs        (16) */
66}
67page_t;
68
69/*************************************************************************************
70 * This function initializes one page descriptor.
71 *************************************************************************************
72 * @ page    : pointer to page descriptor
73 ************************************************************************************/
74inline void page_init( page_t * page );
75
76/*************************************************************************************
77 * This function atomically set one or several flags in page descriptor flags.
78 *************************************************************************************
79 * @ page    : pointer to page descriptor.
80 * @ value   : all non zero bits in value will be set.
81 ************************************************************************************/
82inline void page_set_flag( page_t   * page,
83                           uint32_t   value );
84
85/*************************************************************************************
86 * This function atomically reset one or several flags in page descriptor flags.
87 *************************************************************************************
88 * @ page    : pointer to page descriptor.
89 * @ value   : all non zero bits in value will be cleared.
90 ************************************************************************************/
91inline void page_clear_flag( page_t   * page,
92                             uint32_t   value );
93
94/*************************************************************************************
95 * This function tests the value of one or several flags in page descriptor flags.
96 *************************************************************************************
97 * @ page    : pointer to page descriptor.
98 * @ value   : all non zero bits will be tested.
99 * @ returns true if at least one non zero bit in value is set / false otherwise.
100 ************************************************************************************/
101inline bool_t page_is_flag( page_t   * page,
102                            uint32_t   value );
103
104/*************************************************************************************
105 * This function resets to 0 all bytes in a given page.
106 *************************************************************************************
107 * @ page     : pointer on page descriptor.
108 ************************************************************************************/
109void page_zero( page_t * page );
110
111/*************************************************************************************
112 * This blocking function atomically increments the page refcount.
113 *************************************************************************************
114 * @ page     : pointer on page descriptor.
115 ************************************************************************************/
116inline void page_refcount_up( page_t * page );
117
118/*************************************************************************************
119 * This blocking function atomically decrements the page refcount.
120 *************************************************************************************
121 * @ page     : pointer on page descriptor.
122 ************************************************************************************/
123inline void page_refcount_down( page_t * page );
124
125/*************************************************************************************
126 * This function display the values contained in a page descriptor.
127 *************************************************************************************
128 * @ page     : pointer on page descriptor.
129 ************************************************************************************/
130void page_print( page_t * page );
131
132
133#endif  /* _PAGE_H_ */
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