/* $NetBSD: kvm_i386pae.c,v 1.4 2023/08/23 14:00:11 rin Exp $ */

/*
* Copyright (c) 2010 Jean-Yves Migeon.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: kvm_i386pae.c,v 1.4 2023/08/23 14:00:11 rin Exp $");

/*
* This will expose PAE functions, macros, definitions and constants.
* Note: this affects all virtual memory related functions. Only their
* PAE versions can be used below.
*/
#define PAE

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/kcore.h>
#include <sys/types.h>

#include <stdlib.h>
#include <unistd.h>
#include <nlist.h>
#include <kvm.h>

#include <uvm/uvm_extern.h>

#include <limits.h>
#include <db.h>

#include "kvm_private.h"

#include <i386/kcore.h>
#include <i386/pmap.h>
#include <i386/pte.h>
#include <i386/vmparam.h>

int _kvm_kvatop_i386pae(kvm_t *, vaddr_t, paddr_t *);

/*
* Used to translate a virtual address to a physical address for systems
* running under PAE mode. Three levels of virtual memory pages are handled
* here: the per-CPU L3 page, the 4 L2 PDs and the PTs.
*/
int
_kvm_kvatop_i386pae(kvm_t *kd, vaddr_t va, paddr_t *pa)
{
       cpu_kcore_hdr_t *cpu_kh;
       u_long page_off;
       pd_entry_t pde;
       pt_entry_t pte;
       paddr_t pde_pa, pte_pa;

       cpu_kh = kd->cpu_data;
       page_off = va & PGOFSET;

       /*
        * Find and read the PDE. Ignore the L3, as it is only a per-CPU
        * page, not needed for kernel VA => PA translations.
        * Remember that the 4 L2 pages are contiguous, so it is safe
        * to increment pdppaddr to compute the address of the PDE.
        * pdppaddr being PAGE_SIZE aligned, we mask the option bits.
        */
       pde_pa = (cpu_kh->pdppaddr & PTE_FRAME) + (pl2_pi(va) * sizeof(pde));
       if (_kvm_pread(kd, kd->pmfd, (void *)&pde, sizeof(pde),
           _kvm_pa2off(kd, pde_pa)) != sizeof(pde)) {
               _kvm_syserr(kd, 0, "could not read PDE");
               goto lose;
       }

       /*
        * Find and read the page table entry.
        */
       if ((pde & PTE_P) == 0) {
               _kvm_err(kd, 0, "invalid translation (invalid PDE)");
               goto lose;
       }
       if ((pde & PTE_PS) != 0) {
               /*
                * This is a 2MB page.
                */
               page_off = va & ((vaddr_t)~PTE_LGFRAME);
               *pa = (pde & PTE_LGFRAME) + page_off;
               return (int)(NBPD_L2 - page_off);
       }

       pte_pa = (pde & PTE_FRAME) + (pl1_pi(va) * sizeof(pt_entry_t));
       if (_kvm_pread(kd, kd->pmfd, (void *) &pte, sizeof(pte),
           _kvm_pa2off(kd, pte_pa)) != sizeof(pte)) {
               _kvm_syserr(kd, 0, "could not read PTE");
               goto lose;
       }

       /*
        * Validate the PTE and return the physical address.
        */
       if ((pte & PTE_P) == 0) {
               _kvm_err(kd, 0, "invalid translation (invalid PTE)");
               goto lose;
       }
       *pa = (pte & PTE_FRAME) + page_off;
       return (int)(NBPG - page_off);

lose:
       *pa = (paddr_t)~0L;
       return 0;

}