source: trunk/hal/generic/hal_gpt.h @ 41

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1/*
2 * hal_gpt.h - Generic Page Table API definition.
3 *
4 * Authors  Alain Greiner (2016)
5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#ifndef _GPT_H_
25#define _GPT_H_
26
27#include <hal_types.h>
28
29/////////////////////////////////////////////////////////////////////////////////////////
30//           Generic Page Table Definition (implementation in hal_gpt.c)
31//
32// It is specified as a simple (one dimensional) array indexed by the VPN (vpn_t type),
33// even if implementations can use a more sophisticated organisation (two-levels or more).
34// - The number of entries (number of pages in a virtual space) is architecture
35//   dependent, and is defined as (CONFIG_USER_SPACE_SIZE / CONFIG_PPM_PAGE_SIZE).
36// - Each entry contains a Physical Page Number (ppn_t type), and a set of attributes,
37//   defined as masks on a 32 bits-vector.
38//
39// Any arch-specific implementation must implement this API.
40/////////////////////////////////////////////////////////////////////////////////////////
41
42/****  Forward declarations  ****/
43
44struct page_s;
45
46/****************************************************************************************
47 * These global variables define the masks for the Generic Page Table Entry attributes.
48 * The actual values must be defined in the implementation (hal_gpt.c file).
49 ***************************************************************************************/
50
51extern uint32_t  GPT_MAPPED;         /*! PTE is mapped                                 */
52extern uint32_t  GPT_SMALL;          /*! PTE is a small page                           */
53extern uint32_t  GPT_READABLE;       /*! PTE is readable                               */
54extern uint32_t  GPT_WRITABLE;       /*! PTE is writable                               */
55extern uint32_t  GPT_EXECUTABLE;     /*! PTE is executable                             */
56extern uint32_t  GPT_CACHABLE;       /*! PTE can be cached                             */
57extern uint32_t  GPT_USER;           /*! PTE is user accessible                        */
58extern uint32_t  GPT_DIRTY;          /*! PTE has been "recently" written               */
59extern uint32_t  GPT_ACCESSED;       /*! PTE has been "recently" accessed              */
60extern uint32_t  GPT_GLOBAL;         /*! PTE is kept in TLB at context switch          */
61extern uint32_t  GPT_COW;            /*! PTE must be copied on write                   */
62extern uint32_t  GPT_SWAP;           /*! PTE swapped on disk (not implemented yet)     */
63extern uint32_t  GPT_LOCKED;         /*! PTE is protected against concurrent access    */
64
65/****************************************************************************************
66 * This structure defines the Generic Page Table descriptor.
67 ***************************************************************************************/
68
69typedef struct gpt_s
70{
71        void           * ptr;    /*! pointer on GPT root (must be page aligned)            */
72        ppn_t            ppn;    /*! PPN of GPT root                                       */
73        struct page_s  * page;   /*! pointer on page descriptor for GPT root               */
74}
75gpt_t;
76
77
78/****************************************************************************************
79 * This function allocates physical memory for first level page table (PT1),
80 * and initializes the page table descriptor.
81 ****************************************************************************************
82 * @ gpt     : pointer on generic page table descriptor.
83 * @ returns 0 if success / returns ENOMEM if error.
84 ***************************************************************************************/
85error_t hal_gpt_create( gpt_t * gpt );
86
87/****************************************************************************************
88 * This function releases all memory dynamically allocated for a generic page table.
89 * For a multi-levels radix tree implementation, it includes all nodes in the tree.
90 * If the calling thread is running in the reference cluster, it checks that user PTE
91 * entries are unmapped, and releases the mapped physical pages.
92 * The kernel pages are not released.
93 ****************************************************************************************
94 * @ gpt     : pointer on generic page table descriptor.
95 ***************************************************************************************/
96void hal_gpt_destroy( gpt_t * gpt);
97
98/****************************************************************************************
99 * This function prints on the kernel terminal the content of a generic page table.
100 ****************************************************************************************
101 * @ gpt     : pointer on generic page table descriptor.
102 ***************************************************************************************/
103void hal_gpt_print( gpt_t * gpt);
104
105/****************************************************************************************
106 * This blocking function gets a lock on a PTE (Page Table Entry) identified
107 * by its VPN, and returns only when the PTE has been successfully locked.
108 * If the target PTE is not present, it allocates and maps a physical page.
109 * A big page cannot be locked.
110 ****************************************************************************************
111 * @ gpt     : pointer on the generic page table
112 * @ vpn     : virtual page number of the target PTE.
113 * @ returns 0 if success / return ENOMEM or EINVAL if error.
114 ***************************************************************************************/
115error_t hal_gpt_lock_pte( gpt_t * gpt,
116                          vpn_t   vpn );
117
118/****************************************************************************************
119 * This function releases the lock on a PTE identified by its VPN.
120 ****************************************************************************************
121 * @ gpt     : pointer on the generic page table
122 * @ vpn     : virtual page number of the target PTE.
123 * @ returns 0 if success / returns EINVAL if error.
124 ***************************************************************************************/
125error_t hal_gpt_unlock_pte( gpt_t * gpt,
126                            vpn_t   vpn );
127
128/****************************************************************************************
129 * This function maps a page table entry identified by its VPN, from values defined
130 * by the ppn and attr arguments. It allocates physical memory for the local generic
131 * page table itself if required.
132 ****************************************************************************************
133 * @ gpt       : [in] pointer on the page table
134 * @ vpn       : [in] virtual page number
135 * @ ppn       : [in] physical page number
136 * @ attr      : [in] generic attributes
137 * @ returns 0 if success / returns ENOMEM if error
138 ***************************************************************************************/
139error_t hal_gpt_set_pte( gpt_t    * gpt,
140                         vpn_t      vpn,
141                         ppn_t      ppn,
142                         uint32_t   attr );
143
144/****************************************************************************************
145 * This function unmaps a page table entry identified by its VPN.
146 * If the calling thread is running in the reference cluster, it sends a broadcast RPC
147 * to update all other page table copies.
148 ****************************************************************************************
149 * @ gpt       : [in] pointer on the page table
150 * @ vpn       : [in] virtual page number
151 ***************************************************************************************/
152void hal_gpt_reset_pte( gpt_t * gpt,
153                        vpn_t   vpn );
154
155/****************************************************************************************
156 * This function returns in the ppn and attr arguments the value of a page table
157 * entry identified by its VPN.  It returns attr == 0 if the page is not mapped.
158 ****************************************************************************************
159 * @ gpt       : [in]  pointer on the page table
160 * @ vpn       : [in]  virtual page number
161 * @ attr      : [out] generic attributes
162 * @ ppn       : [out] physical page number
163 ***************************************************************************************/
164void hal_gpt_get_pte( gpt_t    * gpt,
165                      vpn_t      vpn,
166                      uint32_t * attr,
167                      ppn_t    * ppn );
168
169/****************************************************************************************
170 * This function copies all valid entries from the source <src_gpt> to the <dst_pgt>.
171 * The <src_gpt> and the <dst_gpt> point on the same physical pages.
172 * If the <cow> argument is true, the GPT_WRITABLE attribute is reset for all writable
173 * entries in both <src_gpt> and <dst_gpt>, and the PG_COW flag is registered in all
174 * writable physical page descriptors, to support the Copy-On-Write mechanism.
175 ****************************************************************************************
176 * @ dst_gpt   : [in]  pointer on the destination GPT.
177 * @ src_gpt   : [in]  pointer on the source GPT.
178 * @ cow       : [in]  activate the COPY-On-Write mechanism if true.
179 ***************************************************************************************/
180error_t hal_gpt_copy( gpt_t    * dst_gpt,
181                      gpt_t    * src_gpt,
182                      bool_t     cow );
183
184
185#endif  /* _GPT_H_ */
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