98a8e8b486
(domU only). PAE support is enabled by 'options PAE', see the new XEN3PAE_DOMU
and INSTALL_XEN3PAE_DOMU kernel config files.
See the comments in arch/i386/include/{pte.h,pmap.h} to see how it works.
In short, we still handle it as a 2-level MMU, with the second level page
directory being 4 pages in size. pmap switching is done by switching the
L2 pages in the L3 entries, instead of loading %cr3. This is almost required
by Xen, which handle the last L2 page (the one mapping 0xc0000000 - 0xffffffff)
in a very special way. But this approach should also work for native PAE
support if ever supported (in fact, the pmap should almost suport native
PAE, what's missing is bootstrap code in locore.S).
276 lines
12 KiB
C
276 lines
12 KiB
C
/* $NetBSD: pte.h,v 1.17 2008/01/23 19:46:44 bouyer Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 2001 Wasabi Systems, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* Written by Frank van der Linden for Wasabi Systems, Inc.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed for the NetBSD Project by
|
|
* Wasabi Systems, Inc.
|
|
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
|
|
* or promote products derived from this software without specific prior
|
|
* written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
|
|
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/*
|
|
*
|
|
* Copyright (c) 1997 Charles D. Cranor and Washington University.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgment:
|
|
* This product includes software developed by Charles D. Cranor and
|
|
* Washington University.
|
|
* 4. The name of the author may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/*
|
|
* pte.h rewritten by chuck based on the jolitz version, plus random
|
|
* info on the pentium and other processors found on the net. the
|
|
* goal of this rewrite is to provide enough documentation on the MMU
|
|
* hardware that the reader will be able to understand it without having
|
|
* to refer to a hardware manual.
|
|
*/
|
|
|
|
#ifndef _I386_PTE_H_
|
|
#define _I386_PTE_H_
|
|
#ifdef _KERNEL_OPT
|
|
#include "opt_xen.h"
|
|
#endif
|
|
|
|
/*
|
|
* i386 MMU hardware structure (without PAE extention):
|
|
*
|
|
* the i386 MMU is a two-level MMU which maps 4GB of virtual memory.
|
|
* the pagesize is 4K (4096 [0x1000] bytes), although newer pentium
|
|
* processors can support a 4MB pagesize as well.
|
|
*
|
|
* the first level table (segment table?) is called a "page directory"
|
|
* and it contains 1024 page directory entries (PDEs). each PDE is
|
|
* 4 bytes (an int), so a PD fits in a single 4K page. this page is
|
|
* the page directory page (PDP). each PDE in a PDP maps 4MB of space
|
|
* (1024 * 4MB = 4GB). a PDE contains the physical address of the
|
|
* second level table: the page table. or, if 4MB pages are being used,
|
|
* then the PDE contains the PA of the 4MB page being mapped.
|
|
*
|
|
* a page table consists of 1024 page table entries (PTEs). each PTE is
|
|
* 4 bytes (an int), so a page table also fits in a single 4K page. a
|
|
* 4K page being used as a page table is called a page table page (PTP).
|
|
* each PTE in a PTP maps one 4K page (1024 * 4K = 4MB). a PTE contains
|
|
* the physical address of the page it maps and some flag bits (described
|
|
* below).
|
|
*
|
|
* the processor has a special register, "cr3", which points to the
|
|
* the PDP which is currently controlling the mappings of the virtual
|
|
* address space.
|
|
*
|
|
* the following picture shows the translation process for a 4K page:
|
|
*
|
|
* %cr3 register [PA of PDP]
|
|
* |
|
|
* |
|
|
* | bits <31-22> of VA bits <21-12> of VA bits <11-0>
|
|
* | index the PDP (0 - 1023) index the PTP are the page offset
|
|
* | | | |
|
|
* | v | |
|
|
* +--->+----------+ | |
|
|
* | PD Page | PA of v |
|
|
* | |---PTP-------->+------------+ |
|
|
* | 1024 PDE | | page table |--PTE--+ |
|
|
* | entries | | (aka PTP) | | |
|
|
* +----------+ | 1024 PTE | | |
|
|
* | entries | | |
|
|
* +------------+ | |
|
|
* | |
|
|
* bits <31-12> bits <11-0>
|
|
* p h y s i c a l a d d r
|
|
*
|
|
* the i386 caches PTEs in a TLB. it is important to flush out old
|
|
* TLB mappings when making a change to a mappings. writing to the
|
|
* %cr3 will flush the entire TLB. newer processors also have an
|
|
* instruction that will invalidate the mapping of a single page (which
|
|
* is useful if you are changing a single mappings because it preserves
|
|
* all the cached TLB entries).
|
|
*
|
|
* as shows, bits 31-12 of the PTE contain PA of the page being mapped.
|
|
* the rest of the PTE is defined as follows:
|
|
* bit# name use
|
|
* 11 n/a available for OS use, hardware ignores it
|
|
* 10 n/a available for OS use, hardware ignores it
|
|
* 9 n/a available for OS use, hardware ignores it
|
|
* 8 G global bit (see discussion below)
|
|
* 7 PS page size [for PDEs] (0=4k, 1=4M <if supported>)
|
|
* 6 D dirty (modified) page
|
|
* 5 A accessed (referenced) page
|
|
* 4 PCD cache disable
|
|
* 3 PWT prevent write through (cache)
|
|
* 2 U/S user/supervisor bit (0=supervisor only, 1=both u&s)
|
|
* 1 R/W read/write bit (0=read only, 1=read-write)
|
|
* 0 P present (valid)
|
|
*
|
|
* notes:
|
|
* - on the i386 the R/W bit is ignored if processor is in supervisor
|
|
* state (bug!)
|
|
* - PS is only supported on newer processors
|
|
* - PTEs with the G bit are global in the sense that they are not
|
|
* flushed from the TLB when %cr3 is written (to flush, use the
|
|
* "flush single page" instruction). this is only supported on
|
|
* newer processors. this bit can be used to keep the kernel's
|
|
* TLB entries around while context switching. since the kernel
|
|
* is mapped into all processes at the same place it does not make
|
|
* sense to flush these entries when switching from one process'
|
|
* pmap to another.
|
|
*
|
|
* The PAE extention extends the size of the PTE to 64 bits (52bits physical
|
|
* address) and is compatible with the amd64 PTE format. The first level
|
|
* maps 2M, the second 1G, so a third level page table is intruduced to
|
|
* map the 4GB virtual address space. This PD has only 4 entries.
|
|
* We can't use recursive mapping at level 3 to map the PD pages, as
|
|
* this would eat one GB of address space. In addition, Xen impose restrictions
|
|
* on the entries we put in the L3 page (for example, the page pointed to by
|
|
* the last slot can't be shared among different L3 pages), which makes
|
|
* handling this L3 page in the same way we do for L2 on i386 (or L4 on amd64)
|
|
* difficult. For most things we'll just pretend to have only 2 levels,
|
|
* with the 2 high bits of the L2 index being in fact the index in the
|
|
* L3.
|
|
*/
|
|
|
|
#if !defined(_LOCORE)
|
|
|
|
/*
|
|
* here we define the data types for PDEs and PTEs
|
|
*/
|
|
#ifdef PAE
|
|
typedef uint64_t pd_entry_t; /* PDE */
|
|
typedef uint64_t pt_entry_t; /* PTE */
|
|
#else
|
|
typedef uint32_t pd_entry_t; /* PDE */
|
|
typedef uint32_t pt_entry_t; /* PTE */
|
|
#endif
|
|
|
|
#endif
|
|
|
|
/*
|
|
* now we define various for playing with virtual addresses
|
|
*/
|
|
|
|
#ifdef PAE
|
|
#define L1_SHIFT 12
|
|
#define L2_SHIFT 21
|
|
#define L3_SHIFT 30
|
|
#define NBPD_L1 (1ULL << L1_SHIFT) /* # bytes mapped by L1 ent (4K) */
|
|
#define NBPD_L2 (1ULL << L2_SHIFT) /* # bytes mapped by L2 ent (2MB) */
|
|
#define NBPD_L3 (1ULL << L3_SHIFT) /* # bytes mapped by L3 ent (1GB) */
|
|
|
|
#define L3_MASK 0xc0000000
|
|
#define L2_REALMASK 0x3fe00000
|
|
#define L2_MASK (L2_REALMASK | L3_MASK)
|
|
#define L1_MASK 0x001ff000
|
|
|
|
#define L3_FRAME (L3_MASK)
|
|
#define L2_FRAME (L3_FRAME | L2_MASK)
|
|
#define L1_FRAME (L2_FRAME|L1_MASK)
|
|
|
|
#define PG_FRAME 0x000ffffffffff000ULL /* page frame mask */
|
|
#define PG_LGFRAME 0x000fffffffe00000ULL /* large (2MB) page frame mask */
|
|
|
|
/* macros to get real L2 and L3 index, from our "extended" L2 index */
|
|
#define l2tol3(idx) ((idx) >> (L3_SHIFT - L2_SHIFT))
|
|
#define l2tol2(idx) ((idx) & (L2_REALMASK >> L2_SHIFT))
|
|
#else /* PAE */
|
|
#define L1_SHIFT 12
|
|
#define L2_SHIFT 22
|
|
#define NBPD_L1 (1ULL << L1_SHIFT) /* # bytes mapped by L1 ent (4K) */
|
|
#define NBPD_L2 (1ULL << L2_SHIFT) /* # bytes mapped by L2 ent (4MB) */
|
|
|
|
#define L2_MASK 0xffc00000
|
|
#define L1_MASK 0x003ff000
|
|
|
|
#define L2_FRAME (L2_MASK)
|
|
#define L1_FRAME (L2_FRAME|L1_MASK)
|
|
|
|
#define PG_FRAME 0xfffff000 /* page frame mask */
|
|
#define PG_LGFRAME 0xffc00000 /* large (4MB) page frame mask */
|
|
|
|
#endif /* PAE */
|
|
/*
|
|
* here we define the bits of the PDE/PTE, as described above:
|
|
*
|
|
* XXXCDC: need to rename these (PG_u == ugly).
|
|
*/
|
|
|
|
#define PG_V 0x00000001 /* valid entry */
|
|
#define PG_RO 0x00000000 /* read-only page */
|
|
#define PG_RW 0x00000002 /* read-write page */
|
|
#define PG_u 0x00000004 /* user accessible page */
|
|
#define PG_PROT 0x00000806 /* all protection bits */
|
|
#define PG_N 0x00000018 /* non-cacheable */
|
|
#define PG_U 0x00000020 /* has been used */
|
|
#define PG_M 0x00000040 /* has been modified */
|
|
#define PG_PS 0x00000080 /* 4MB page size */
|
|
#define PG_G 0x00000100 /* global, don't TLB flush */
|
|
#define PG_AVAIL1 0x00000200 /* ignored by hardware */
|
|
#define PG_AVAIL2 0x00000400 /* ignored by hardware */
|
|
#define PG_AVAIL3 0x00000800 /* ignored by hardware */
|
|
|
|
/*
|
|
* various short-hand protection codes
|
|
*/
|
|
|
|
#define PG_KR 0x00000000 /* kernel read-only */
|
|
#define PG_KW 0x00000002 /* kernel read-write */
|
|
#define PG_NX 0 /* dummy */
|
|
|
|
/*
|
|
* page protection exception bits
|
|
*/
|
|
|
|
#define PGEX_P 0x01 /* protection violation (vs. no mapping) */
|
|
#define PGEX_W 0x02 /* exception during a write cycle */
|
|
#define PGEX_U 0x04 /* exception while in user mode (upl) */
|
|
|
|
#endif /* _I386_PTE_H_ */
|