FreeBSD/Linux Kernel Cross Reference
sys/i386/include/pmap_pae.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1991 Regents of the University of California.
      * All rights reserved.
      *
      * Copyright (c) 2018 The FreeBSD Foundation
      * All rights reserved.
      *
     * This code is derived from software contributed to Berkeley by
     * the Systems Programming Group of the University of Utah Computer
     * Science Department and William Jolitz of UUNET Technologies Inc.
     *
     * Portions of this software were developed by
     * Konstantin Belousov <kib@FreeBSD.org> under sponsorship from
     * the FreeBSD Foundation.
     *
     * 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. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
     *
     * Derived from hp300 version by Mike Hibler, this version by William
     * Jolitz uses a recursive map [a pde points to the page directory] to
     * map the page tables using the pagetables themselves. This is done to
     * reduce the impact on kernel virtual memory for lots of sparse address
     * space, and to reduce the cost of memory to each process.
     *
     *      from: hp300: @(#)pmap.h 7.2 (Berkeley) 12/16/90
     *      from: @(#)pmap.h        7.4 (Berkeley) 5/12/91
     * $FreeBSD$
     */
    
    #ifndef _MACHINE_PMAP_PAE_H
    #define _MACHINE_PMAP_PAE_H
    
    #define NTRPPTD         2               /* Number of PTDs for trampoline
                                               mapping */
    #define LOWPTDI         2               /* low memory map pde */
    #define KERNPTDI        4               /* start of kernel text pde */
    
    #define NPGPTD          4               /* Num of pages for page directory */
    #define NPGPTD_SHIFT    9
    #undef  PDRSHIFT
    #define PDRSHIFT        PDRSHIFT_PAE
    #undef  NBPDR
    #define NBPDR           (1 << PDRSHIFT_PAE)     /* bytes/page dir */
    
    #define PG_FRAME        PG_FRAME_PAE
    #define PG_PS_FRAME     PG_PS_FRAME_PAE
    
    /*
     * Size of Kernel address space.  This is the number of page table pages
     * (4MB each) to use for the kernel.  256 pages == 1 Gigabyte.
     * This **MUST** be a multiple of 4 (eg: 252, 256, 260, etc).
     * For PAE, the page table page unit size is 2MB.  This means that 512 pages
     * is 1 Gigabyte.  Double everything.  It must be a multiple of 8 for PAE.
     */
    #define KVA_PAGES       (512*4)
    
    /*
     * The initial number of kernel page table pages that are constructed
     * by pmap_cold() must be sufficient to map vm_page_array.  That number can
     * be calculated as follows:
     *     max_phys / PAGE_SIZE * sizeof(struct vm_page) / NBPDR
     * PAE:      max_phys 16G, sizeof(vm_page) 76, NBPDR 2M, 152 page table pages.
     * PAE_TABLES: max_phys 4G,  sizeof(vm_page) 68, NBPDR 2M, 36 page table pages.
     * Non-PAE:  max_phys 4G,  sizeof(vm_page) 68, NBPDR 4M, 18 page table pages.
     */
    #ifndef NKPT
    #define NKPT            240
    #endif
    
    typedef uint64_t pdpt_entry_t;
    typedef uint64_t pd_entry_t;
    typedef uint64_t pt_entry_t;
    
    #define PTESHIFT        (3)
    #define PDESHIFT        (3)
    
   #define pde_cmpset(pdep, old, new)      atomic_cmpset_64_i586(pdep, old, new)
   #define pte_load_store(ptep, pte)       atomic_swap_64_i586(ptep, pte)
   #define pte_load_clear(ptep)            atomic_swap_64_i586(ptep, 0)
   #define pte_store(ptep, pte)            atomic_store_rel_64_i586(ptep, pte)
   #define pte_store_zero(ptep, pte)               \
   do {                                            \
           uint32_t *p;                            \
                                                   \
           MPASS((*ptep & PG_V) == 0);             \
           p = (void *)ptep;                       \
           *(p + 1) = (uint32_t)(pte >> 32);       \
           __compiler_membar();                    \
           *p = (uint32_t)pte;                     \
   } while (0)
   #define pte_load(ptep)                  atomic_load_acq_64_i586(ptep)
   
   extern pdpt_entry_t *IdlePDPT;
   extern pt_entry_t pg_nx;
   extern pd_entry_t *IdlePTD_pae; /* physical address of "Idle" state directory */
   
   /*
    * KPTmap is a linear mapping of the kernel page table.  It differs from the
    * recursive mapping in two ways: (1) it only provides access to kernel page
    * table pages, and not user page table pages, and (2) it provides access to
    * a kernel page table page after the corresponding virtual addresses have
    * been promoted to a 2/4MB page mapping.
    *
    * KPTmap is first initialized by pmap_cold() to support just NPKT page table
    * pages.  Later, it is reinitialized by pmap_bootstrap() to allow for
    * expansion of the kernel page table.
    */
   extern pt_entry_t *KPTmap_pae;
   
   #endif

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