102 lines
3.0 KiB
C
102 lines
3.0 KiB
C
/* Copyright (C) 2005 David Decotigny
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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_MMCTXT_H_
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#define _SOS_MMCTXT_H_
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/**
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* @file mm_context.h
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*
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* Low level API to manage multiple MMU translation tables. The API
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* (not its implementation) should be some kind of
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* architecture-independent.
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*
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* The goal of this API is:
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* - To provide a simple arch-independent API to change the current
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* address space configured in the MMU
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* - To make sure that ALL the kernel space mappings are always kept
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* IDENTICAL among all the address spaces in the whole system. That
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* way, a virtual address in the kernel space refers to EXACTLY the
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* same physical memory location for all the address spaces.
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*/
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#include <sos/types.h>
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#include <sos/errno.h>
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/**
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* Declaration of an MMU context. Opaque structure defined in
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* mm_context.c
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*/
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struct sos_mm_context;
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/**
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* Setup the MMU context management subsystem
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*/
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sos_ret_t sos_mm_context_subsystem_setup();
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/**
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* Public function to allocate a new MMU context.
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*
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* Allocate a new PD, map it into kernel virtual address space and
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* initialize its PDE for the Kernel space so that the Kernel space is
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* kept identical between ALL the MMU context in the system.
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*/
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struct sos_mm_context * sos_mm_context_create(void);
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/**
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* Public function to release the given MMU context (based on
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* reference counting). Only the virtual page that maps the PD of the
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* MMU context is released. All the other user-space pages are
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* expected to be already released by the parent process.
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*/
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sos_ret_t sos_mm_context_unref(struct sos_mm_context *mmctxt);
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/**
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* Reconfigure the MMU to use a different MMU context. mmctxt MUST
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* NOT be NULL.
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*/
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sos_ret_t sos_mm_context_switch_to(struct sos_mm_context *mmctxt);
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/* ******************************************************
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* Reserved functions
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*/
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/**
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* Reserved function to increase the reference count of the given MMU
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* context (based on reference counting).
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*/
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sos_ret_t sos_mm_context_ref(struct sos_mm_context *mmctxt);
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/**
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* Restricted function reserved to paging.c to synchronize all the PDEs
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* accross all the MMU contexts in the system. This is limited to PDEs
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* pertaining to the kernel space.
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*/
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sos_ret_t sos_mm_context_synch_kernel_PDE(unsigned int index_in_pd,
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sos_ui32_t pde);
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#endif /* _SOS_MMCTXT_H_ */
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