IABSD.fr/src/lib/libkvm/kvm_amd64.c

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• Author : mmcc
  Date : 2015-12-19 18:40:30
  Hash : a42e4c92
  Message : Remove NULL-checks before free(). ok tb@

• lib/libkvm/kvm_amd64.c

• /*	$OpenBSD: kvm_amd64.c,v 1.13 2015/12/19 18:40:30 mmcc Exp $	*/
  /*	$NetBSD: kvm_x86_64.c,v 1.3 2002/06/05 22:01:55 fvdl Exp $	*/
  
  /*-
   * 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.
   */
  
  /*
   * x86-64 machine dependent routines for kvm.
   */
  
  #include <sys/param.h>	/* MAXCOMLEN */
  #include <sys/proc.h>
  #include <sys/stat.h>
  #include <sys/kcore.h>
  #include <machine/kcore.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 <machine/pmap.h>
  #include <machine/pte.h>
  #include <machine/vmparam.h>
  
  void
  _kvm_freevtop(kvm_t *kd)
  {
  	/* Not actually used for anything right now, but safe. */
  	free(kd->vmst);
  	kd->vmst = NULL;
  }
  
  /*ARGSUSED*/
  int
  _kvm_initvtop(kvm_t *kd)
  {
  
  	return (0);
  }
  
  /*
   * Translate a kernel virtual address to a physical address.
   */
  int
  _kvm_kvatop(kvm_t *kd, u_long va, paddr_t *pa)
  {
  	cpu_kcore_hdr_t *cpu_kh;
  	paddr_t pde_pa, pte_pa;
  	u_long page_off;
  	pd_entry_t pde;
  	pt_entry_t pte;
  
  	if (ISALIVE(kd)) {
  		_kvm_err(kd, 0, "vatop called in live kernel!");
  		return (0);
  	}
  
  	page_off = va & (kd->nbpg - 1);
  
  	if (va >= PMAP_DIRECT_BASE && va <= PMAP_DIRECT_END) {
  		*pa = va - PMAP_DIRECT_BASE;
  		return (int)(kd->nbpg - page_off);
  	}
  
  	cpu_kh = kd->cpu_data;
  
  	/*
  	 * Find and read all entries to get to the pa.
  	 */
  
  	/*
  	 * Level 4.
  	 */
  	pde_pa = cpu_kh->ptdpaddr + (pl4_pi(va) * sizeof(pd_entry_t));
  	if (pread(kd->pmfd, (void *)&pde, sizeof(pde),
  	    _kvm_pa2off(kd, pde_pa)) != sizeof(pde)) {
  		_kvm_syserr(kd, 0, "could not read PT level 4 entry");
  		goto lose;
  	}
  	if ((pde & PG_V) == 0) {
  		_kvm_err(kd, 0, "invalid translation (invalid level 4 PDE)");
  		goto lose;
  	}
  
  	/*
  	 * Level 3.
  	 */
  	pde_pa = (pde & PG_FRAME) + (pl3_pi(va) * sizeof(pd_entry_t));
  	if (pread(kd->pmfd, (void *)&pde, sizeof(pde),
  	    _kvm_pa2off(kd, pde_pa)) != sizeof(pde)) {
  		_kvm_syserr(kd, 0, "could not read PT level 3 entry");
  		goto lose;
  	}
  	if ((pde & PG_V) == 0) {
  		_kvm_err(kd, 0, "invalid translation (invalid level 3 PDE)");
  		goto lose;
  	}
  
  	/*
  	 * Level 2.
  	 */
  	pde_pa = (pde & PG_FRAME) + (pl2_pi(va) * sizeof(pd_entry_t));
  	if (pread(kd->pmfd, (void *)&pde, sizeof(pde),
  	    _kvm_pa2off(kd, pde_pa)) != sizeof(pde)) {
  		_kvm_syserr(kd, 0, "could not read PT level 2 entry");
  		goto lose;
  	}
  	if ((pde & PG_V) == 0) {
  		_kvm_err(kd, 0, "invalid translation (invalid level 2 PDE)");
  		goto lose;
  	}
  
  	/*
  	 * Might be a large page.
  	 */
  	if ((pde & PG_PS) != 0) {
  		page_off = va & (NBPD_L2 - 1);
  		*pa = (pde & PG_LGFRAME) | page_off;
  		return (int)(NBPD_L2 - page_off);
  	}
  
  	/*
  	 * Level 1.
  	 */
  	pte_pa = (pde & PG_FRAME) + (pl1_pi(va) * sizeof(pt_entry_t));
  	if (pread(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 & PG_V) == 0) {
  		_kvm_err(kd, 0, "invalid translation (invalid PTE)");
  		goto lose;
  	}
  	*pa = (pte & PG_FRAME) + page_off;
  	return (int)(kd->nbpg - page_off);
  
   lose:
  	*pa = (u_long)~0L;
  	return (0);
  }
  
  /*
   * Translate a physical address to a file-offset in the crash dump.
   */
  off_t
  _kvm_pa2off(kvm_t *kd, paddr_t pa)
  {
  	cpu_kcore_hdr_t *cpu_kh;
  	phys_ram_seg_t *ramsegs;
  	off_t off;
  	int i;
  
  	cpu_kh = kd->cpu_data;
  	ramsegs = (void *)((char *)(void *)cpu_kh + ALIGN(sizeof *cpu_kh));
  
  	off = 0;
  	for (i = 0; i < cpu_kh->nmemsegs; i++) {
  		if (pa >= ramsegs[i].start &&
  		    (pa - ramsegs[i].start) < ramsegs[i].size) {
  			off += (pa - ramsegs[i].start);
  			break;
  		}
  		off += ramsegs[i].size;
  	}
  
  	if (i == cpu_kh->nmemsegs)
  		_kvm_err(kd, 0, "pa %lx not in dump", pa);
  
  	return (kd->dump_off + off);
  }