FreeBSD/Linux Kernel Cross Reference
sys/cddl/dev/dtrace/x86/instr_size.c

     /*
      * CDDL HEADER START
      *
      * The contents of this file are subject to the terms of the
      * Common Development and Distribution License, Version 1.0 only
      * (the "License").  You may not use this file except in compliance
      * with the License.
      *
      * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
     * or http://www.opensolaris.org/os/licensing.
     * See the License for the specific language governing permissions
     * and limitations under the License.
     *
     * When distributing Covered Code, include this CDDL HEADER in each
     * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     * If applicable, add the following below this CDDL HEADER, with the
     * fields enclosed by brackets "[]" replaced with your own identifying
     * information: Portions Copyright [yyyy] [name of copyright owner]
     *
     * CDDL HEADER END
     *
     * $FreeBSD$
     */
    /*
     * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
     * Use is subject to license terms.
     */
    
    /*      Copyright (c) 1988 AT&T */
    /*        All Rights Reserved   */
    
    
    #ifdef illumos
    #pragma ident   "@(#)instr_size.c       1.14    05/07/08 SMI"
    #endif
    
    #include <sys/types.h>
    #include <sys/param.h>
    #include <sys/proc.h>
    #ifdef illumos
    #include <sys/cmn_err.h>
    #include <sys/archsystm.h>
    #include <sys/copyops.h>
    #include <vm/seg_enum.h>
    #include <sys/privregs.h>
    #else
    #include <sys/cred.h>
    #include <cddl/dev/dtrace/dtrace_cddl.h>
    
    typedef u_int                   model_t;
    #define DATAMODEL_NATIVE        0
    int dtrace_instr_size(uchar_t *);
    int dtrace_instr_size_isa(uchar_t *, model_t, int *);
    #endif
    
    #include <dis_tables.h>
    
    /*
     * This subsystem (with the minor exception of the instr_size() function) is
     * is called from DTrace probe context.  This imposes several requirements on
     * the implementation:
     *
     * 1. External subsystems and functions may not be referenced.  The one current
     *    exception is for cmn_err, but only to signal the detection of table
     *    errors.  Assuming the tables are correct, no combination of input is to
     *    trigger a cmn_err call.
     *
     * 2. These functions can't be allowed to be traced.  To prevent this,
     *    all functions in the probe path (everything except instr_size()) must
     *    have names that begin with "dtrace_".
     */
    
    typedef enum dis_isize {
            DIS_ISIZE_INSTR,
            DIS_ISIZE_OPERAND
    } dis_isize_t;
    
    
    /*
     * get a byte from instruction stream
     */
    static int
    dtrace_dis_get_byte(void *p)
    {
            int ret;
            uchar_t **instr = p;
    
            ret = **instr;
            *instr += 1;
    
            return (ret);
    }
    
    /*
     * Returns either the size of a given instruction, in bytes, or the size of that
     * instruction's memory access (if any), depending on the value of `which'.
     * If a programming error in the tables is detected, the system will panic to
     * ease diagnosis.  Invalid instructions will not be flagged.  They will appear
     * to have an instruction size between 1 and the actual size, and will be
    * reported as having no memory impact.
    */
   /* ARGSUSED2 */
   static int
   dtrace_dis_isize(uchar_t *instr, dis_isize_t which, model_t model, int *rmindex)
   {
           int sz;
           dis86_t x;
           uint_t mode = SIZE32;
   
           mode = (model == DATAMODEL_LP64) ? SIZE64 : SIZE32;
   
           x.d86_data = (void **)&instr;
           x.d86_get_byte = dtrace_dis_get_byte;
           x.d86_check_func = NULL;
   
           if (dtrace_disx86(&x, mode) != 0)
                   return (-1);
   
           if (which == DIS_ISIZE_INSTR)
                   sz = x.d86_len;         /* length of the instruction */
           else
                   sz = x.d86_memsize;     /* length of memory operand */
   
           if (rmindex != NULL)
                   *rmindex = x.d86_rmindex;
           return (sz);
   }
   
   int
   dtrace_instr_size_isa(uchar_t *instr, model_t model, int *rmindex)
   {
           return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, model, rmindex));
   }
   
   int
   dtrace_instr_size(uchar_t *instr)
   {
           return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE,
               NULL));
   }

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