source: trunk/kernel/mm/page.h @ 606

Last change on this file since 606 was 606, checked in by alain, 6 years ago

Improve the FAT32 file system to support cat, rm, cp commands.
File size: 6.7 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 * TODO : the PG_BUFFER and PG_IO_ERR flags semantic is not defined [AG]
40 ************************************************************************************/
41
42#define PG_INIT             0x0001     // page descriptor has been initialised
43#define PG_RESERVED         0x0002     // cannot be allocated by PPM
44#define PG_FREE             0x0004     // page can be allocated by PPM
45#define PG_IO_ERR           0x0010     // mapper signals access error    TODO ??? [AG]
46#define PG_BUFFER           0x0020     // used in blockio.c              TODO ??? [AG]
47#define PG_DIRTY            0x0040     // page has been written
48#define PG_COW          0x0080     // page is copy-on-write
49
50/*************************************************************************************
51 * This structure defines a physical page descriptor.
52 * - The remote_busylock is used to allows any remote thread to atomically
53 *   test/modify the forks counter or the page flags.
54 * - The list entry is used to register the page in a free list or in dirty list.
55 * NOTE: Size is 48 bytes for a 32 bits core.
56 * TODO : the refcount use is not defined [AG]
57 ************************************************************************************/
58
59typedef struct page_s
60{
61    uint32_t          flags;          /*! flags defined above                  (4)  */
62    uint32_t          order;          /*! log2( number of small pages)         (4)  */
63    struct mapper_s * mapper;         /*! local pointer on associated mapper   (4)  */
64    uint32_t          index;          /*! page index in mapper                 (4)  */
65        list_entry_t      list;           /*! for both dirty pages and free pages  (8)  */
66        uint32_t          refcount;       /*! reference counter TODO ??? [AG]      (4)  */
67        uint32_t          forks;          /*! number of pending forks              (4)  */
68        remote_busylock_t lock;           /*! protect forks or flags modifs        (16) */
69}
70page_t;
71
72/*************************************************************************************
73 * This function initializes one page descriptor.
74 *************************************************************************************
75 * @ page    : pointer to page descriptor
76 ************************************************************************************/
77inline void page_init( page_t * page );
78
79/*************************************************************************************
80 * This function atomically set one or several flags in page descriptor flags.
81 *************************************************************************************
82 * @ page    : pointer to page descriptor.
83 * @ value   : all non zero bits in value will be set.
84 ************************************************************************************/
85inline void page_set_flag( page_t   * page,
86                           uint32_t   value );
87
88/*************************************************************************************
89 * This function atomically reset one or several flags in page descriptor flags.
90 *************************************************************************************
91 * @ page    : pointer to page descriptor.
92 * @ value   : all non zero bits in value will be cleared.
93 ************************************************************************************/
94inline void page_clear_flag( page_t   * page,
95                             uint32_t   value );
96
97/*************************************************************************************
98 * This function tests the value of one or several flags in page descriptor flags.
99 *************************************************************************************
100 * @ page    : pointer to page descriptor.
101 * @ value   : all non zero bits will be tested.
102 * @ returns true if at least one non zero bit in value is set / false otherwise.
103 ************************************************************************************/
104inline bool_t page_is_flag( page_t   * page,
105                            uint32_t   value );
106
107/*************************************************************************************
108 * This function resets to 0 all bytes in a given page.
109 *************************************************************************************
110 * @ page     : pointer on page descriptor.
111 ************************************************************************************/
112void page_zero( page_t * page );
113
114/*************************************************************************************
115 * This blocking function atomically increments the page refcount.
116 *************************************************************************************
117 * @ page     : pointer on page descriptor.
118 ************************************************************************************/
119inline void page_refcount_up( page_t * page );
120
121/*************************************************************************************
122 * This blocking function atomically decrements the page refcount.
123 *************************************************************************************
124 * @ page     : pointer on page descriptor.
125 ************************************************************************************/
126inline void page_refcount_down( page_t * page );
127
128/*************************************************************************************
129 * This function display the values contained in a page descriptor.
130 *************************************************************************************
131 * @ page     : pointer on page descriptor.
132 ************************************************************************************/
133void page_print( page_t * page );
134
135
136#endif  /* _PAGE_H_ */
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