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001 /* Copyright (C) 2004 David Decotigny 002 003 This program is free software; you can redistribute it and/or 004 modify it under the terms of the GNU General Public License 005 as published by the Free Software Foundation; either version 2 006 of the License, or (at your option) any later version. 007 008 This program is distributed in the hope that it will be useful, 009 but WITHOUT ANY WARRANTY; without even the implied warranty of 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 011 GNU General Public License for more details. 012 013 You should have received a copy of the GNU General Public License 014 along with this program; if not, write to the Free Software 015 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 016 USA. 017 */ 018 #ifndef _SOS_PAGING_H_ 019 #define _SOS_PAGING_H_ 020 021 /** 022 * @file paging.h 023 * 024 * MMU management routines (arch-dependent). Setup the MMU without 025 * identity-mapping physical<->virtual addresses over the whole 026 * physical address space: a single, restricted and known, area is 027 * identity-mapped, the remaining kernel/user space is not. To access 028 * and manage the MMU translation tables (PD/PT on x86), we rely on a 029 * particular configuration, called "mirroring", where the top-level 030 * translation table (PD on x86) maps itself at a known and fixed (virtual) 031 * address. The only assumption for this to be possible is that the 032 * structure of the translation table entries are compatible at the 033 * different levels of vadddr->paddr translation process (PDE and PTE 034 * on x86 are Ok). Credits go to Christophe Avoinne for that. 035 */ 036 037 #include <sos/types.h> 038 #include <sos/errno.h> 039 040 041 /** 042 * Basic SOS virtual memory organization 043 */ 044 /** Frontier between kernel and user space virtual addresses */ 045 #define SOS_PAGING_BASE_USER_ADDRESS (0x40000000) /* 1GB (must be 4MB-aligned) */ 046 #define SOS_PAGING_TOP_USER_ADDRESS (0xFFFFFFFF) /* 4GB - 1B */ 047 #define SOS_PAGING_USER_SPACE_SIZE (0xc0000000) /* 3GB */ 048 049 /** Length of the space reserved for the mirroring in the kernel 050 virtual space */ 051 #define SOS_PAGING_MIRROR_SIZE (1 << 22) /* 1 PD = 1024 Page Tables = 4MB */ 052 053 /** Virtual address where the mirroring takes place */ 054 #define SOS_PAGING_MIRROR_VADDR \ 055 (SOS_PAGING_BASE_USER_ADDRESS - SOS_PAGING_MIRROR_SIZE) 056 057 058 /** 059 * sos_paging_map flags 060 */ 061 /** Usual virtual memory access rights */ 062 #define SOS_VM_MAP_PROT_NONE 0 063 #define SOS_VM_MAP_PROT_READ (1<<0) 064 #define SOS_VM_MAP_PROT_WRITE (1<<1) 065 #define SOS_VM_MAP_PROT_EXEC (1<<2) /* Not supported on IA32 */ 066 067 /** Mapping a page may involve an physical page allocation (for a new 068 PT), hence may potentially block */ 069 #define SOS_VM_MAP_ATOMIC (1<<31) 070 071 072 /** 073 * Setup initial page directory structure where the kernel is 074 * identically-mapped, and the mirroring. This routine also 075 * identity-maps the BIOS and video areas, to allow some debugging 076 * text to be printed to the console. Finally, this routine installs 077 * the whole configuration into the MMU. 078 */ 079 sos_ret_t sos_paging_subsystem_setup(sos_paddr_t identity_mapping_base, 080 sos_paddr_t identity_mapping_top); 081 082 /** 083 * Map the given physical page at the given virtual address in the 084 * current address space. 085 * 086 * @note *IMPORTANT*: The physical page ppage_paddr *MUST* have been 087 * referenced by the caller through either a call to 088 * sos_physmem_ref_physpage_new() or sos_physmem_ref_physpage_at(). It 089 * would work if this were untrue, but this would be INCORRECT (it is 090 * expected that one is owning the page before mapping it, or 091 * otherwise the page could have been stolen by an interrupt or 092 * another thread). 093 * 094 * @param ppage_paddr The address of a physical page (page-aligned) 095 * @param vpage_vaddr The address of the virtual page (page-aligned) 096 * @param is_user_page TRUE when the page is available from user space 097 * @param flags A mask made of SOS_VM_* bits 098 * 099 * @note Unless the SOS_VM_MAP_ATOMIC bit is set in the flags, the 100 * function may potentially block, because a physical page may be 101 * allocated for a new PT. 102 */ 103 sos_ret_t sos_paging_map(sos_paddr_t ppage_paddr, 104 sos_vaddr_t vpage_vaddr, 105 sos_bool_t is_user_page, 106 sos_ui32_t flags); 107 108 /** 109 * Undo the mapping from vaddr to the underlying physical page (if any) 110 * @param vpage_vaddr The address of the virtual page (page-aligned) 111 * 112 * @return >= 0 when OK (the number of bytes of RAM unmapped), < 0 on error 113 */ 114 sos_ret_t sos_paging_unmap(sos_vaddr_t vpage_vaddr); 115 116 /** 117 * Undo the mapping from [vaddr .. vaddr + size[ to the underlying 118 * physical pages (if any) 119 * @param vpage_vaddr The address of the virtual page (page-aligned) 120 * @param size The size (in bytes) to unmap. MUST be page-aligned 121 */ 122 sos_ret_t sos_paging_unmap_interval(sos_vaddr_t base_vpage_vaddr, 123 sos_size_t size); 124 125 /** 126 * Return the page protection flags (SOS_VM_MAP_PROT_*) associated 127 * with the address, or SOS_VM_MAP_PROT_NONE when page is not mapped 128 */ 129 sos_ui32_t sos_paging_get_prot(sos_vaddr_t vaddr); 130 131 /** 132 * Change the page access rights 133 */ 134 sos_ret_t sos_paging_set_prot(sos_vaddr_t vaddr, 135 sos_ui32_t new_prot); 136 137 /** 138 * Change the access rights of the mapping from [vaddr .. vaddr + 139 * size[ to the underlying physical pages (if any) 140 * @param vpage_vaddr The address of the virtual page (page-aligned) 141 * @param size The size (in bytes) to unmap. MUST be page-aligned 142 */ 143 sos_ret_t sos_paging_set_prot_of_interval(sos_vaddr_t vaddr, 144 sos_size_t size, 145 sos_ui32_t new_prot); 146 147 /** 148 * Return the physical address of the given virtual address. Since page 149 * at physical addr 0 is not mapped, the NULL result means "page not 150 * mapped". 151 */ 152 sos_paddr_t sos_paging_get_paddr(sos_vaddr_t vaddr); 153 154 /** 155 * Tell whether the address is physically mapped 156 */ 157 #define sos_paging_check_present(vaddr) \ 158 (sos_paging_get_paddr(vaddr) != NULL) 159 160 161 /* ************************************************* 162 * Functions restricted to mm_context module 163 */ 164 165 166 /** 167 * Release the references to all the referenced pages (and PT on 168 * x86). On x86, this applies only to the USER pages and PT. 169 */ 170 sos_ret_t sos_paging_dispose(sos_vaddr_t vaddr_PD); 171 172 173 /** 174 * Copy the MMU configuration related to the kernel virtual area 175 */ 176 sos_ret_t sos_paging_copy_kernel_space(sos_vaddr_t dest_vaddr_PD, 177 sos_vaddr_t src_vaddr_PD); 178 179 180 /** 181 * Copy the MMU configuration related to the user virtual area 182 */ 183 sos_ret_t sos_paging_copy_user_space(sos_vaddr_t dest_vaddr_PD, 184 sos_vaddr_t src_vaddr_PD); 185 186 187 /** 188 * Prepare the *current* address space for COW on the given *private* 189 * mapping 190 */ 191 sos_ret_t sos_paging_prepare_COW(sos_uaddr_t base_address, 192 sos_size_t length); 193 194 195 /** 196 * Try to resolve the given page fault exception by a COW. 197 * 198 * @param uaddr The user-space address (of the current MMU context) of 199 * the faulting access 200 * 201 * @return TRUE if the page fault was a real COW and could be handled, 202 * FALSE if the page fault is not subject to COW (no physical mem 203 * mapped at this address). <0 in case the given address is subject to 204 * COW BUT could not be resolved due to runtime errors 205 */ 206 sos_ret_t sos_paging_try_resolve_COW(sos_uaddr_t uaddr); 207 208 209 /** 210 * Retrieve the current physical address of the PD 211 */ 212 sos_paddr_t sos_paging_get_current_PD_paddr(); 213 214 215 /** 216 * Change the current MMU configuration. 217 * 218 * @note DANGEROUS. Don't use it unless you know exactly what you're 219 * doing ! 220 */ 221 sos_ret_t sos_paging_set_current_PD_paddr(sos_paddr_t paddr_PD); 222 223 #endif /* _SOS_PAGING_H_ */
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