206 lines
6.7 KiB
C
206 lines
6.7 KiB
C
/* Copyright (C) 2004 David Decotigny
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Copyright (C) 2000 The KOS Team
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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USA.
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*/
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#ifndef _SOS_PHYSMEM_H_
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#define _SOS_PHYSMEM_H_
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/**
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* @file physmem.h
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*
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* Physical pages of memory
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*/
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#include <sos/errno.h>
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#include <sos/types.h>
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#include <sos/macros.h>
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/** The size of a physical page (arch-dependent) */
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#define SOS_PAGE_SIZE (4*1024)
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/** The corresponding shift */
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#define SOS_PAGE_SHIFT 12 /* 4 kB = 2^12 B */
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/** The corresponding mask */
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#define SOS_PAGE_MASK ((1<<12) - 1)
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#define SOS_PAGE_ALIGN_INF(val) \
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SOS_ALIGN_INF((val), SOS_PAGE_SIZE)
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#define SOS_PAGE_ALIGN_SUP(val) \
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SOS_ALIGN_SUP((val), SOS_PAGE_SIZE)
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#define SOS_IS_PAGE_ALIGNED(val) \
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SOS_IS_ALIGNED((val), SOS_PAGE_SIZE)
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/**
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* This is the reserved physical interval for the x86 video memory and
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* BIOS area. In physmem.c, we have to mark this area as "nonfree" in
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* order to prevent from allocating it. And in paging.c, we'd better
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* map it in virtual space if we really want to be able to print to
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* the screen (for debugging purpose, at least): for this, the
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* simplest is to identity-map this area in virtual space (note
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* however that this mapping could also be non-identical).
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*/
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#define BIOS_N_VIDEO_START 0xa0000
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#define BIOS_N_VIDEO_END 0x100000
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/**
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* Initialize the physical memory subsystem, for the physical area [0,
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* ram_size). This routine takes into account the BIOS and video
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* areas, to prevent them from future allocations.
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*
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* @param ram_size The size of the RAM that will be managed by this subsystem
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*
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* @param kernel_core_base The lowest address for which the kernel
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* assumes identity mapping (ie virtual address == physical address)
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* will be stored here
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*
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* @param kernel_core_top The top address for which the kernel
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* assumes identity mapping (ie virtual address == physical address)
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* will be stored here
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*/
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sos_ret_t sos_physmem_subsystem_setup(sos_size_t ram_size,
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/* out */sos_paddr_t *kernel_core_base,
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/* out */sos_paddr_t *kernel_core_top);
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/**
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* Retrieve the total number of pages, and the number of free pages
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*
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* @note both parameters may be NULL
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*/
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sos_ret_t sos_physmem_get_state(/* out */sos_count_t *total_ppages,
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/* out */sos_count_t *nonfree_ppages);
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/**
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* Get a free page.
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*
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* @return The (physical) address of the (physical) page allocated, or
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* NULL when none currently available.
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*
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* @param can_block TRUE if the function is allowed to block
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* @note The page returned has a reference count equal to 1.
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*/
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sos_paddr_t sos_physmem_ref_physpage_new(sos_bool_t can_block);
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/**
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* Increment the reference count of a given physical page. Useful for
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* VM code which tries to map a precise physical address.
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*
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* @param ppage_paddr Physical address of the page (MUST be page-aligned)
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*
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* @return TRUE when the page was previously referenced, FALSE when
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* the page was previously unreferenced, <0 when the page address is
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* invalid.
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*/
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sos_ret_t sos_physmem_ref_physpage_at(sos_paddr_t ppage_paddr);
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/**
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* Decrement the reference count of the given physical page. When the
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* reference count of the page reaches 0, the page is marked free, ie
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* is available for future sos_physmem_ref_physpage_new()
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*
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* @param ppage_paddr Physical address of the page (MUST be page-aligned)
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*
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* @return FALSE when the page is still referenced, TRUE when the page
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* is now unreferenced, <0 when the page address is invalid
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*/
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sos_ret_t sos_physmem_unref_physpage(sos_paddr_t ppage_paddr);
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/**
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* Return the reference count of the given page
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*
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* @return >= 0 (the referebce count of the page) if the physical
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* address is valid, or an error status
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*/
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sos_ret_t sos_physmem_get_physpage_refcount(sos_paddr_t ppage_paddr);
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/*
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* In some cases (Page Tables on x86 for example), the physical pages
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* might contain a set of slots available for "allocation" (x86
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* example: a PT contains a set of PTE). We provide here a set of
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* functions to manage a per-page additional counter that holds this
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* number of slots currently in use in the page.
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*
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* A newly allocated physical page has a occupation count of 0.
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*
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* The management of this counter is up to the subsystem that manages
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* the page (mainly: paging), however a simple set of rules applies:
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* - it can only be incremented/decremented if the page is referenced
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* - when it reaches 0, no automatic action is undertaken
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* The first rule means in particular that a page whose reference
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* count reaches 0 (=> being freed) cannot have a occupation_cnt
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* value > 0 ! The system will be HALTED if this ever happens
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*/
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/**
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* Increment the occupation count of the given physical page.
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*
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* @param ppage_paddr Physical address of the page (MUST be page-aligned)
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*
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* @return TRUE when the occupation count was previously NON-ZERO, FALSE
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* when this occupation count was 0, <0 when the page address is invalid.
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*
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* @note the page MUST be marked as REFERENCED by somebody !
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*/
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sos_ret_t sos_physmem_inc_physpage_occupation(sos_paddr_t ppage_paddr);
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/**
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* Decrement the occupation count of the given physical page.
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*
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* @param ppage_paddr Physical address of the page (MUST be page-aligned)
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*
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* @return FALSE when the occupation count is still NON-ZERO, TRUE when the
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* page now is ZERO, <0 when the page address is invalid
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*
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* @note the page MUST be marked as REFERENCED by somebody !
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*/
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sos_ret_t sos_physmem_dec_physpage_occupation(sos_paddr_t ppage_paddr);
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#include <sos/kmem_vmm.h>
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/**
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* Return the kernel memory allocation range associated with the given
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* physical page, or NULL when page has no associated range
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*
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* @param ppage_paddr Physical address of the page (MUST be page-aligned)
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*/
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struct sos_kmem_range* sos_physmem_get_kmem_range(sos_paddr_t ppage_paddr);
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/**
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* Set the kernel memory allocation range associated to the given
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* physical page.
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*
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* @param ppage_paddr Physical address of the page (MUST be page-aligned)
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*
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* @return error if page is invalid
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*/
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sos_ret_t sos_physmem_set_kmem_range(sos_paddr_t ppage_paddr,
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struct sos_kmem_range *range);
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#endif /* _SOS_PHYSMEM_H_ */
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