1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22/* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27/* Copyright (c) 1988 AT&T */ 28/* All Rights Reserved */ 29 30 31/* 32 * #pragma ident "@(#)instr_size.c 1.14 05/07/08 SMI" 33 */ 34 35#include <sys/dtrace.h> 36#include <sys/dtrace_glue.h> 37 38#include <sys/dis_tables.h> 39 40/* 41 * This subsystem (with the minor exception of the instr_size() function) is 42 * is called from DTrace probe context. This imposes several requirements on 43 * the implementation: 44 * 45 * 1. External subsystems and functions may not be referenced. The one current 46 * exception is for cmn_err, but only to signal the detection of table 47 * errors. Assuming the tables are correct, no combination of input is to 48 * trigger a cmn_err call. 49 * 50 * 2. These functions can't be allowed to be traced. To prevent this, 51 * all functions in the probe path (everything except instr_size()) must 52 * have names that begin with "dtrace_". 53 */ 54 55typedef enum dis_isize { 56 DIS_ISIZE_INSTR, 57 DIS_ISIZE_OPERAND 58} dis_isize_t; 59 60 61/* 62 * get a byte from instruction stream 63 */ 64static int 65dtrace_dis_get_byte(void *p) 66{ 67 int ret; 68 uchar_t **instr = p; 69 70 ret = **instr; 71 *instr += 1; 72 73 return (ret); 74} 75 76/* 77 * Returns either the size of a given instruction, in bytes, or the size of that 78 * instruction's memory access (if any), depending on the value of `which'. 79 * If a programming error in the tables is detected, the system will panic to 80 * ease diagnosis. Invalid instructions will not be flagged. They will appear 81 * to have an instruction size between 1 and the actual size, and will be 82 * reported as having no memory impact. 83 */ 84/* ARGSUSED2 */ 85static int 86dtrace_dis_isize(uchar_t *instr, dis_isize_t which, model_t model, int *rmindex) 87{ 88 int sz; 89 dis86_t x; 90 uint_t mode = SIZE32; 91 92 mode = (model == DATAMODEL_LP64) ? SIZE64 : SIZE32; 93 94 x.d86_data = (void **)&instr; 95 x.d86_get_byte = dtrace_dis_get_byte; 96 x.d86_check_func = NULL; 97 98 if (dtrace_disx86(&x, mode) != 0) 99 return (-1); 100 101 if (which == DIS_ISIZE_INSTR) 102 sz = x.d86_len; /* length of the instruction */ 103 else 104 sz = x.d86_memsize; /* length of memory operand */ 105 106 if (rmindex != NULL) 107 *rmindex = x.d86_rmindex; 108 return (sz); 109} 110 111int 112dtrace_instr_size_isa(uchar_t *instr, model_t model, int *rmindex) 113{ 114 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, model, rmindex)); 115} 116 117int 118dtrace_instr_size(uchar_t *instr) 119{ 120 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE, 121 NULL)); 122} 123 124#if !defined(__APPLE__) 125/*ARGSUSED*/ 126int 127instr_size(struct regs *rp, caddr_t *addrp, enum seg_rw rw) 128{ 129 uchar_t instr[16]; /* maximum size instruction */ 130 caddr_t pc = (caddr_t)rp->r_pc; 131 132 (void) copyin_nowatch(pc, (caddr_t)instr, sizeof (instr)); 133 134 return (dtrace_dis_isize(instr, 135 rw == S_EXEC ? DIS_ISIZE_INSTR : DIS_ISIZE_OPERAND, 136 curproc->p_model, NULL)); 137} 138#endif /* __APPLE__ */ 139