130 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			130 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
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 *	The President and Fellows of Harvard College.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#ifndef _MIPS_VM_H_
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#define _MIPS_VM_H_
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/*
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 * Machine-dependent VM system definitions.
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 */
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#define PAGE_SIZE  4096         /* size of VM page */
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#define PAGE_FRAME 0xfffff000   /* mask for getting page number from addr */
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/*
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 * MIPS-I hardwired memory layout:
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 *    0xc0000000 - 0xffffffff   kseg2 (kernel, tlb-mapped)
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 *    0xa0000000 - 0xbfffffff   kseg1 (kernel, unmapped, uncached)
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 *    0x80000000 - 0x9fffffff   kseg0 (kernel, unmapped, cached)
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 *    0x00000000 - 0x7fffffff   kuseg (user, tlb-mapped)
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 *
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 * (mips32 is a little different)
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 */
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#define MIPS_KUSEG  0x00000000
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#define MIPS_KSEG0  0x80000000
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#define MIPS_KSEG1  0xa0000000
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#define MIPS_KSEG2  0xc0000000
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/*
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 * The first 512 megs of physical space can be addressed in both kseg0 and
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 * kseg1. We use kseg0 for the kernel. This macro returns the kernel virtual
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 * address of a given physical address within that range. (We assume we're
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 * not using systems with more physical space than that anyway.)
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 *
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 * N.B. If you, say, call a function that returns a paddr or 0 on error,
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 * check the paddr for being 0 *before* you use this macro. While paddr 0
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 * is not legal for memory allocation or memory management (it holds
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 * exception handler code) when converted to a vaddr it's *not* NULL, *is*
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 * a valid address, and will make a *huge* mess if you scribble on it.
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 */
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#define PADDR_TO_KVADDR(paddr) ((paddr)+MIPS_KSEG0)
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/*
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 * The top of user space. (Actually, the address immediately above the
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 * last valid user address.)
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 */
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#define USERSPACETOP  MIPS_KSEG0
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/*
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 * The starting value for the stack pointer at user level.  Because
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 * the stack is subtract-then-store, this can start as the next
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 * address after the stack area.
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 *
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 * We put the stack at the very top of user virtual memory because it
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 * grows downwards.
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 */
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#define USERSTACK     USERSPACETOP
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/*
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 * Interface to the low-level module that looks after the amount of
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 * physical memory we have.
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 *
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 * ram_getsize returns one past the highest valid physical
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 * address. (This value is page-aligned.)  The extant RAM ranges from
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 * physical address 0 up to but not including this address.
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 *
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 * ram_getfirstfree returns the lowest valid physical address. (It is
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 * also page-aligned.) Memory at this address and above is available
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 * for use during operation, and excludes the space the kernel is
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 * loaded into and memory that is grabbed in the very early stages of
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 * bootup. Memory below this address is already in use and should be
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 * reserved or otherwise not managed by the VM system. It should be
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 * called exactly once when the VM system initializes to take over
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 * management of physical memory.
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 *
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 * ram_stealmem can be used before ram_getsize is called to allocate
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 * memory that cannot be freed later. This is intended for use early
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 * in bootup before VM initialization is complete.
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 */
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void ram_bootstrap(void);
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paddr_t ram_stealmem(unsigned long npages);
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paddr_t ram_getsize(void);
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paddr_t ram_getfirstfree(void);
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/*
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 * TLB shootdown bits.
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 *
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 * We'll take up to 16 invalidations before just flushing the whole TLB.
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 */
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struct tlbshootdown {
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	/*
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	 * Change this to what you need for your VM design.
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	 */
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	int ts_placeholder;
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};
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#define TLBSHOOTDOWN_MAX 16
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#endif /* _MIPS_VM_H_ */
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