1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990 The Regents of the University of California. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * William Jolitz. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)psl.h 5.2 (Berkeley) 1/18/91 35 * $FreeBSD$ 36 */ 37 38 #ifndef _MACHINE_PSL_H_ 39 #define _MACHINE_PSL_H_ 40 41 /* 42 * 386 processor status longword. 43 */ 44 #define PSL_C 0x00000001 /* carry bit */ 45 #define PSL_PF 0x00000004 /* parity bit */ 46 #define PSL_AF 0x00000010 /* bcd carry bit */ 47 #define PSL_Z 0x00000040 /* zero bit */ 48 #define PSL_N 0x00000080 /* negative bit */ 49 #define PSL_T 0x00000100 /* trace enable bit */ 50 #define PSL_I 0x00000200 /* interrupt enable bit */ 51 #define PSL_D 0x00000400 /* string instruction direction bit */ 52 #define PSL_V 0x00000800 /* overflow bit */ 53 #define PSL_IOPL 0x00003000 /* i/o privilege level */ 54 #define PSL_NT 0x00004000 /* nested task bit */ 55 #define PSL_RF 0x00010000 /* resume flag bit */ 56 #define PSL_VM 0x00020000 /* virtual 8086 mode bit */ 57 #define PSL_AC 0x00040000 /* alignment checking */ 58 #define PSL_VIF 0x00080000 /* virtual interrupt enable */ 59 #define PSL_VIP 0x00100000 /* virtual interrupt pending */ 60 #define PSL_ID 0x00200000 /* identification bit */ 61 62 /* 63 * The i486 manual says that we are not supposed to change reserved flags, 64 * but this is too much trouble since the reserved flags depend on the cpu 65 * and setting them to their historical values works in practice. 66 */ 67 #define PSL_RESERVED_DEFAULT 0x00000002 68 69 /* 70 * Initial flags for kernel and user mode. The kernel later inherits 71 * PSL_I and some other flags from user mode. 72 */ 73 #define PSL_KERNEL PSL_RESERVED_DEFAULT 74 #define PSL_USER (PSL_RESERVED_DEFAULT | PSL_I) 75 76 /* 77 * Bits that can be changed in user mode on 486's. We allow these bits 78 * to be changed using ptrace(), sigreturn() and procfs. Setting PS_NT 79 * is undesirable but it may as well be allowed since users can inflict 80 * it on the kernel directly. Changes to PSL_AC are silently ignored on 81 * 386's. 82 * 83 * Users are allowed to change the privileged flag PSL_RF. The cpu sets PSL_RF 84 * in tf_eflags for faults. Debuggers should sometimes set it there too. 85 * tf_eflags is kept in the signal context during signal handling and there is 86 * no other place to remember it, so the PSL_RF bit may be corrupted by the 87 * signal handler without us knowing. Corruption of the PSL_RF bit at worst 88 * causes one more or one less debugger trap, so allowing it is fairly 89 * harmless. 90 */ 91 #define PSL_USERCHANGE (PSL_C | PSL_PF | PSL_AF | PSL_Z | PSL_N | PSL_T \ 92 | PSL_D | PSL_V | PSL_NT | PSL_RF | PSL_AC | PSL_ID) 93 94 #endif /* !_MACHINE_PSL_H_ */ 95