/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software developed by the Computer Systems
 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
 * BG 91-66 and contributed to Berkeley.
 *
 * 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.
 */


/*
 * i386 machine dependent routines for kvm.  Hopefully, the forthcoming
 * vm code will one day obsolete this module.
 */

#include <sys/param.h>
#include <sys/endian.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <vm/vm.h>
#include <kvm.h>

#ifdef __i386__
#include <machine/vmparam.h>            /* For KERNBASE. */
#endif

#include <limits.h>

#include "kvm_private.h"
#include "kvm_i386.h"

struct vmstate {
        void            *PTD;
        int             pae;
        size_t          phnum;
        GElf_Phdr       *phdr;
};

/*
 * Translate a physical memory address to a file-offset in the crash-dump.
 */
static size_t
_kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
{
        struct vmstate *vm = kd->vmst;
        GElf_Phdr *p;
        size_t n;

        if (kd->rawdump) {
                *ofs = pa;
                return (I386_PAGE_SIZE - (pa & I386_PAGE_MASK));
        }

        p = vm->phdr;
        n = vm->phnum;
        while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
                p++, n--;
        if (n == 0)
                return (0);
        *ofs = (pa - p->p_paddr) + p->p_offset;
        return (I386_PAGE_SIZE - (pa & I386_PAGE_MASK));
}

static void
_i386_freevtop(kvm_t *kd)
{
        struct vmstate *vm = kd->vmst;

        if (vm->PTD)
                free(vm->PTD);
        free(vm->phdr);
        free(vm);
        kd->vmst = NULL;
}

static int
_i386_probe(kvm_t *kd)
{

        return (_kvm_probe_elf_kernel(kd, ELFCLASS32, EM_386) &&
            !_kvm_is_minidump(kd));
}

static int
_i386_initvtop(kvm_t *kd)
{
        struct kvm_nlist nl[2];
        i386_physaddr_t pa;
        kvaddr_t kernbase;
        char            *PTD;
        int             i;

        kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(struct vmstate));
        if (kd->vmst == NULL) {
                _kvm_err(kd, kd->program, "cannot allocate vm");
                return (-1);
        }
        kd->vmst->PTD = 0;

        if (kd->rawdump == 0) {
                if (_kvm_read_core_phdrs(kd, &kd->vmst->phnum,
                    &kd->vmst->phdr) == -1)
                        return (-1);
        }

        nl[0].n_name = "kernbase";
        nl[1].n_name = 0;

        if (kvm_nlist2(kd, nl) != 0) {
#ifdef __i386__
                kernbase = KERNBASE;    /* for old kernels */
#else
                _kvm_err(kd, kd->program, "cannot resolve kernbase");
                return (-1);
#endif
        } else
                kernbase = nl[0].n_value;

        nl[0].n_name = "IdlePDPT";
        nl[1].n_name = 0;

        if (kvm_nlist2(kd, nl) == 0) {
                i386_physaddr_pae_t pa64;

                if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa,
                    sizeof(pa)) != sizeof(pa)) {
                        _kvm_err(kd, kd->program, "cannot read IdlePDPT");
                        return (-1);
                }
                pa = le32toh(pa);
                PTD = _kvm_malloc(kd, 4 * I386_PAGE_SIZE);
                if (PTD == NULL) {
                        _kvm_err(kd, kd->program, "cannot allocate PTD");
                        return (-1);
                }
                for (i = 0; i < 4; i++) {
                        if (kvm_read2(kd, pa + (i * sizeof(pa64)), &pa64,
                            sizeof(pa64)) != sizeof(pa64)) {
                                _kvm_err(kd, kd->program, "Cannot read PDPT");
                                free(PTD);
                                return (-1);
                        }
                        pa64 = le64toh(pa64);
                        if (kvm_read2(kd, pa64 & I386_PG_FRAME_PAE,
                            PTD + (i * I386_PAGE_SIZE), I386_PAGE_SIZE) !=
                            I386_PAGE_SIZE) {
                                _kvm_err(kd, kd->program, "cannot read PDPT");
                                free(PTD);
                                return (-1);
                        }
                }
                kd->vmst->PTD = PTD;
                kd->vmst->pae = 1;
        } else {
                nl[0].n_name = "IdlePTD";
                nl[1].n_name = 0;

                if (kvm_nlist2(kd, nl) != 0) {
                        _kvm_err(kd, kd->program, "bad namelist");
                        return (-1);
                }
                if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa,
                    sizeof(pa)) != sizeof(pa)) {
                        _kvm_err(kd, kd->program, "cannot read IdlePTD");
                        return (-1);
                }
                pa = le32toh(pa);
                PTD = _kvm_malloc(kd, I386_PAGE_SIZE);
                if (PTD == NULL) {
                        _kvm_err(kd, kd->program, "cannot allocate PTD");
                        return (-1);
                }
                if (kvm_read2(kd, pa, PTD, I386_PAGE_SIZE) != I386_PAGE_SIZE) {
                        _kvm_err(kd, kd->program, "cannot read PTD");
                        return (-1);
                }
                kd->vmst->PTD = PTD;
                kd->vmst->pae = 0;
        }
        return (0);
}

static int
_i386_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
{
        struct vmstate *vm;
        i386_physaddr_t offset;
        i386_physaddr_t pte_pa;
        i386_pde_t pde;
        i386_pte_t pte;
        kvaddr_t pdeindex;
        kvaddr_t pteindex;
        size_t s;
        i386_physaddr_t a;
        off_t ofs;
        i386_pde_t *PTD;

        vm = kd->vmst;
        PTD = (i386_pde_t *)vm->PTD;
        offset = va & I386_PAGE_MASK;

        /*
         * If we are initializing (kernel page table descriptor pointer
         * not yet set) then return pa == va to avoid infinite recursion.
         */
        if (PTD == NULL) {
                s = _kvm_pa2off(kd, va, pa);
                if (s == 0) {
                        _kvm_err(kd, kd->program,
                            "_i386_vatop: bootstrap data not in dump");
                        goto invalid;
                } else
                        return (I386_PAGE_SIZE - offset);
        }

        pdeindex = va >> I386_PDRSHIFT;
        pde = le32toh(PTD[pdeindex]);
        if ((pde & I386_PG_V) == 0) {
                _kvm_err(kd, kd->program, "_i386_vatop: pde not valid");
                goto invalid;
        }

        if (pde & I386_PG_PS) {
                /*
                 * No second-level page table; ptd describes one 4MB
                 * page.  (We assume that the kernel wouldn't set
                 * PG_PS without enabling it cr0).
                 */
                offset = va & I386_PAGE_PS_MASK;
                a = (pde & I386_PG_PS_FRAME) + offset;
                s = _kvm_pa2off(kd, a, pa);
                if (s == 0) {
                        _kvm_err(kd, kd->program,
                            "_i386_vatop: 4MB page address not in dump");
                        goto invalid;
                }
                return (I386_NBPDR - offset);
        }

        pteindex = (va >> I386_PAGE_SHIFT) & (I386_NPTEPG - 1);
        pte_pa = (pde & I386_PG_FRAME) + (pteindex * sizeof(pte));

        s = _kvm_pa2off(kd, pte_pa, &ofs);
        if (s < sizeof(pte)) {
                _kvm_err(kd, kd->program, "_i386_vatop: pte_pa not found");
                goto invalid;
        }

        /* XXX This has to be a physical address read, kvm_read is virtual */
        if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
                _kvm_syserr(kd, kd->program, "_i386_vatop: pread");
                goto invalid;
        }
        pte = le32toh(pte);
        if ((pte & I386_PG_V) == 0) {
                _kvm_err(kd, kd->program, "_kvm_kvatop: pte not valid");
                goto invalid;
        }

        a = (pte & I386_PG_FRAME) + offset;
        s = _kvm_pa2off(kd, a, pa);
        if (s == 0) {
                _kvm_err(kd, kd->program, "_i386_vatop: address not in dump");
                goto invalid;
        } else
                return (I386_PAGE_SIZE - offset);

invalid:
        _kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
        return (0);
}

static int
_i386_vatop_pae(kvm_t *kd, kvaddr_t va, off_t *pa)
{
        struct vmstate *vm;
        i386_physaddr_pae_t offset;
        i386_physaddr_pae_t pte_pa;
        i386_pde_pae_t pde;
        i386_pte_pae_t pte;
        kvaddr_t pdeindex;
        kvaddr_t pteindex;
        size_t s;
        i386_physaddr_pae_t a;
        off_t ofs;
        i386_pde_pae_t *PTD;

        vm = kd->vmst;
        PTD = (i386_pde_pae_t *)vm->PTD;
        offset = va & I386_PAGE_MASK;

        /*
         * If we are initializing (kernel page table descriptor pointer
         * not yet set) then return pa == va to avoid infinite recursion.
         */
        if (PTD == NULL) {
                s = _kvm_pa2off(kd, va, pa);
                if (s == 0) {
                        _kvm_err(kd, kd->program,
                            "_i386_vatop_pae: bootstrap data not in dump");
                        goto invalid;
                } else
                        return (I386_PAGE_SIZE - offset);
        }

        pdeindex = va >> I386_PDRSHIFT_PAE;
        pde = le64toh(PTD[pdeindex]);
        if ((pde & I386_PG_V) == 0) {
                _kvm_err(kd, kd->program, "_kvm_kvatop_pae: pde not valid");
                goto invalid;
        }

        if (pde & I386_PG_PS) {
                /*
                 * No second-level page table; ptd describes one 2MB
                 * page.  (We assume that the kernel wouldn't set
                 * PG_PS without enabling it cr0).
                 */
                offset = va & I386_PAGE_PS_MASK_PAE;
                a = (pde & I386_PG_PS_FRAME_PAE) + offset;
                s = _kvm_pa2off(kd, a, pa);
                if (s == 0) {
                        _kvm_err(kd, kd->program,
                            "_i386_vatop: 2MB page address not in dump");
                        goto invalid;
                }
                return (I386_NBPDR_PAE - offset);
        }

        pteindex = (va >> I386_PAGE_SHIFT) & (I386_NPTEPG_PAE - 1);
        pte_pa = (pde & I386_PG_FRAME_PAE) + (pteindex * sizeof(pde));

        s = _kvm_pa2off(kd, pte_pa, &ofs);
        if (s < sizeof(pte)) {
                _kvm_err(kd, kd->program, "_i386_vatop_pae: pdpe_pa not found");
                goto invalid;
        }

        /* XXX This has to be a physical address read, kvm_read is virtual */
        if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
                _kvm_syserr(kd, kd->program, "_i386_vatop_pae: read");
                goto invalid;
        }
        pte = le64toh(pte);
        if ((pte & I386_PG_V) == 0) {
                _kvm_err(kd, kd->program, "_i386_vatop_pae: pte not valid");
                goto invalid;
        }

        a = (pte & I386_PG_FRAME_PAE) + offset;
        s = _kvm_pa2off(kd, a, pa);
        if (s == 0) {
                _kvm_err(kd, kd->program,
                    "_i386_vatop_pae: address not in dump");
                goto invalid;
        } else
                return (I386_PAGE_SIZE - offset);

invalid:
        _kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
        return (0);
}

static int
_i386_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
{

        if (ISALIVE(kd)) {
                _kvm_err(kd, 0, "vatop called in live kernel!");
                return (0);
        }
        if (kd->vmst->pae)
                return (_i386_vatop_pae(kd, va, pa));
        else
                return (_i386_vatop(kd, va, pa));
}

int
_i386_native(kvm_t *kd __unused)
{

#ifdef __i386__
        return (1);
#else
        return (0);
#endif
}

static struct kvm_arch kvm_i386 = {
        .ka_probe = _i386_probe,
        .ka_initvtop = _i386_initvtop,
        .ka_freevtop = _i386_freevtop,
        .ka_kvatop = _i386_kvatop,
        .ka_native = _i386_native,
};

KVM_ARCH(kvm_i386);