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The LXR Cross Referencer for SOS

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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_PHYSMEM_H_
019 #define _SOS_PHYSMEM_H_
020 
021 /**
022  * @file physmem.h
023  *
024  * Physical pages of memory
025  */
026 
027 #include <sos/errno.h>
028 #include <sos/types.h>
029 #include <sos/macros.h>
030 
031 /** The size of a physical page (arch-dependent) */
032 #define SOS_PAGE_SIZE  (4*1024)
033 
034 /** The corresponding shift */
035 #define SOS_PAGE_SHIFT 12 /* 4 kB = 2^12 B */
036 
037 /** The corresponding mask */
038 #define SOS_PAGE_MASK  ((1<<12) - 1)
039 
040 #define SOS_PAGE_ALIGN_INF(val) \
041   SOS_ALIGN_INF((val), SOS_PAGE_SIZE)
042 #define SOS_PAGE_ALIGN_SUP(val) \
043   SOS_ALIGN_SUP((val), SOS_PAGE_SIZE)
044 
045 
046 /**
047  * This is the reserved physical interval for the x86 video memory and
048  * BIOS area. In physmem.c, we have to mark this area as "used" in
049  * order to prevent from allocating it. And in paging.c, we'd better
050  * map it in virtual space if we really want to be able to print to
051  * the screen (for debugging purpose, at least): for this, the
052  * simplest is to identity-map this area in virtual space (note
053  * however that this mapping could also be non-identical).
054  */
055 #define BIOS_N_VIDEO_START 0xa0000
056 #define BIOS_N_VIDEO_END   0x100000
057 
058 
059 /**
060  * Initialize the physical memory subsystem, for the physical area [0,
061  * ram_size). This routine takes into account the BIOS and video
062  * areas, to prevent them from future allocations.
063  *
064  * @param ram_size The size of the RAM that will be managed by this subsystem
065  *
066  * @param kernel_core_base The lowest address for which the kernel
067  * assumes identity mapping (ie virtual address == physical address)
068  * will be stored here
069  *
070  * @param kernel_core_top The top address for which the kernel
071  * assumes identity mapping (ie virtual address == physical address)
072  * will be stored here
073  */
074 sos_ret_t sos_physmem_setup(sos_size_t ram_size,
075                             /* out */sos_paddr_t *kernel_core_base,
076                             /* out */sos_paddr_t *kernel_core_top);
077 
078 /**
079  * Retrieve the total number of pages, and the number of free pages
080  */
081 sos_ret_t sos_physmem_get_state(/* out */sos_count_t *total_ppages,
082                                 /* out */sos_count_t *used_ppages);
083 
084 
085 /**
086  * Get a free page.
087  *
088  * @return The (physical) address of the (physical) page allocated, or
089  * NULL when none currently available.
090  *
091  * @param can_block TRUE if the function is allowed to block
092  * @note The page returned has a reference count equal to 1.
093  */
094 sos_paddr_t sos_physmem_ref_physpage_new(sos_bool_t can_block);
095 
096 
097 /**
098  * Increment the reference count of a given physical page. Useful for
099  * VM code which tries to map a precise physical address.
100  *
101  * @return TRUE when the page was previously in use, FALSE when the
102  * page was previously in the free list, <0 when the page address is
103  * invalid.
104  */
105 sos_ret_t sos_physmem_ref_physpage_at(sos_paddr_t ppage_paddr);
106 
107 
108 /**
109  * Decrement the reference count of the given physical page. When this
110  * reference count reaches 0, the page is marked free, ie is available
111  * for future sos_physmem_get_physpage()
112  *
113  * @return FALSE when the page is still in use, TRUE when the page is now
114  * unreferenced, <0 when the page address is invalid
115  */
116 sos_ret_t sos_physmem_unref_physpage(sos_paddr_t ppage_paddr);
117 
118 
119 #include <sos/kmem_vmm.h>
120 
121 /**
122  * Return the kernel memory allocation range associated with the given
123  * physical page, or NULL when page has no associated range
124  */
125 struct sos_kmem_range* sos_physmem_get_kmem_range(sos_paddr_t ppage_paddr);
126 
127 
128 /**
129  * Set the kernel memory allocation range associated to the given
130  * physical page.
131  * @return error if page is invalid
132  */
133 sos_ret_t sos_physmem_set_kmem_range(sos_paddr_t ppage_paddr,
134                                      struct sos_kmem_range *range);
135 
136 #endif /* _SOS_PHYSMEM_H_ */

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