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001 /* Copyright (C) 2004 David Decotigny 002 Copyright (C) 2000 The KOS Team 003 004 This program is free software; you can redistribute it and/or 005 modify it under the terms of the GNU General Public License 006 as published by the Free Software Foundation; either version 2 007 of the License, or (at your option) any later version. 008 009 This program is distributed in the hope that it will be useful, 010 but WITHOUT ANY WARRANTY; without even the implied warranty of 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 012 GNU General Public License for more details. 013 014 You should have received a copy of the GNU General Public License 015 along with this program; if not, write to the Free Software 016 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 017 USA. 018 */ 019 #ifndef _SOS_PHYSMEM_H_ 020 #define _SOS_PHYSMEM_H_ 021 022 /** 023 * @file physmem.h 024 * 025 * Physical pages of memory 026 */ 027 028 #include <sos/errno.h> 029 #include <sos/types.h> 030 #include <sos/macros.h> 031 032 /** The size of a physical page (arch-dependent) */ 033 #define SOS_PAGE_SIZE (4*1024) 034 035 /** The corresponding shift */ 036 #define SOS_PAGE_SHIFT 12 /* 4 kB = 2^12 B */ 037 038 /** The corresponding mask */ 039 #define SOS_PAGE_MASK ((1<<12) - 1) 040 041 #define SOS_PAGE_ALIGN_INF(val) \ 042 SOS_ALIGN_INF((val), SOS_PAGE_SIZE) 043 #define SOS_PAGE_ALIGN_SUP(val) \ 044 SOS_ALIGN_SUP((val), SOS_PAGE_SIZE) 045 #define SOS_IS_PAGE_ALIGNED(val) \ 046 SOS_IS_ALIGNED((val), SOS_PAGE_SIZE) 047 048 /** 049 * This is the reserved physical interval for the x86 video memory and 050 * BIOS area. In physmem.c, we have to mark this area as "nonfree" in 051 * order to prevent from allocating it. And in paging.c, we'd better 052 * map it in virtual space if we really want to be able to print to 053 * the screen (for debugging purpose, at least): for this, the 054 * simplest is to identity-map this area in virtual space (note 055 * however that this mapping could also be non-identical). 056 */ 057 #define BIOS_N_VIDEO_START 0xa0000 058 #define BIOS_N_VIDEO_END 0x100000 059 060 061 /** 062 * Initialize the physical memory subsystem, for the physical area [0, 063 * ram_size). This routine takes into account the BIOS and video 064 * areas, to prevent them from future allocations. 065 * 066 * @param ram_size The size of the RAM that will be managed by this subsystem 067 * 068 * @param kernel_core_base The lowest address for which the kernel 069 * assumes identity mapping (ie virtual address == physical address) 070 * will be stored here 071 * 072 * @param kernel_core_top The top address for which the kernel 073 * assumes identity mapping (ie virtual address == physical address) 074 * will be stored here 075 */ 076 sos_ret_t sos_physmem_subsystem_setup(sos_size_t ram_size, 077 /* out */sos_paddr_t *kernel_core_base, 078 /* out */sos_paddr_t *kernel_core_top); 079 080 /** 081 * Retrieve the total number of pages, and the number of free pages 082 */ 083 sos_ret_t sos_physmem_get_state(/* out */sos_count_t *total_ppages, 084 /* out */sos_count_t *nonfree_ppages); 085 086 087 /** 088 * Get a free page. 089 * 090 * @return The (physical) address of the (physical) page allocated, or 091 * NULL when none currently available. 092 * 093 * @param can_block TRUE if the function is allowed to block 094 * @note The page returned has a reference count equal to 1. 095 */ 096 sos_paddr_t sos_physmem_ref_physpage_new(sos_bool_t can_block); 097 098 099 /** 100 * Increment the reference count of a given physical page. Useful for 101 * VM code which tries to map a precise physical address. 102 * 103 * @param ppage_paddr Physical address of the page (MUST be page-aligned) 104 * 105 * @return TRUE when the page was previously referenced, FALSE when 106 * the page was previously unreferenced, <0 when the page address is 107 * invalid. 108 */ 109 sos_ret_t sos_physmem_ref_physpage_at(sos_paddr_t ppage_paddr); 110 111 112 /** 113 * Decrement the reference count of the given physical page. When the 114 * reference count of the page reaches 0, the page is marked free, ie 115 * is available for future sos_physmem_ref_physpage_new() 116 * 117 * @param ppage_paddr Physical address of the page (MUST be page-aligned) 118 * 119 * @return FALSE when the page is still referenced, TRUE when the page 120 * is now unreferenced, <0 when the page address is invalid 121 */ 122 sos_ret_t sos_physmem_unref_physpage(sos_paddr_t ppage_paddr); 123 124 125 /** 126 * Return the reference count of the given page 127 * 128 * @return >= 0 (the referebce count of the page) if the physical 129 * address is valid, or an error status 130 */ 131 sos_ret_t sos_physmem_get_physpage_refcount(sos_paddr_t ppage_paddr); 132 133 134 135 /* 136 * In some cases (Page Tables on x86 for example), the physical pages 137 * might contain a set of slots available for "allocation" (x86 138 * example: a PT contains a set of PTE). We provide here a set of 139 * functions to manage a per-page additional counter that holds this 140 * number of slots currently in use in the page. 141 * 142 * A newly allocated physical page has a occupation count of 0. 143 * 144 * The management of this counter is up to the subsystem that manages 145 * the page (mainly: paging), however a simple set of rules applies: 146 * - it can only be incremented/decremented if the page is referenced 147 * - when it reaches 0, no automatic action is undertaken 148 * The first rule means in particular that a page whose reference 149 * count reaches 0 (=> being freed) cannot have a occupation_cnt 150 * value > 0 ! The system will be HALTED if this ever happens 151 */ 152 153 154 /** 155 * Increment the occupation count of the given physical page. 156 * 157 * @param ppage_paddr Physical address of the page (MUST be page-aligned) 158 * 159 * @return TRUE when the occupation count was previously NON-ZERO, FALSE 160 * when this occupation count was 0, <0 when the page address is invalid. 161 * 162 * @note the page MUST be marked as REFERENCED by somebody ! 163 */ 164 sos_ret_t sos_physmem_inc_physpage_occupation(sos_paddr_t ppage_paddr); 165 166 167 /** 168 * Decrement the occupation count of the given physical page. 169 * 170 * @param ppage_paddr Physical address of the page (MUST be page-aligned) 171 * 172 * @return FALSE when the occupation count is still NON-ZERO, TRUE when the 173 * page now is ZERO, <0 when the page address is invalid 174 * 175 * @note the page MUST be marked as REFERENCED by somebody ! 176 */ 177 sos_ret_t sos_physmem_dec_physpage_occupation(sos_paddr_t ppage_paddr); 178 179 180 #include <sos/kmem_vmm.h> 181 182 /** 183 * Return the kernel memory allocation range associated with the given 184 * physical page, or NULL when page has no associated range 185 * 186 * @param ppage_paddr Physical address of the page (MUST be page-aligned) 187 */ 188 struct sos_kmem_range* sos_physmem_get_kmem_range(sos_paddr_t ppage_paddr); 189 190 191 /** 192 * Set the kernel memory allocation range associated to the given 193 * physical page. 194 * 195 * @param ppage_paddr Physical address of the page (MUST be page-aligned) 196 * 197 * @return error if page is invalid 198 */ 199 sos_ret_t sos_physmem_set_kmem_range(sos_paddr_t ppage_paddr, 200 struct sos_kmem_range *range); 201 202 #endif /* _SOS_PHYSMEM_H_ */
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