1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * William Jolitz. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)psl.h 5.2 (Berkeley) 1/18/91 33 * $FreeBSD: head/sys/x86/include/psl.h 258135 2013-11-14 15:37:20Z emaste $ 34 */ 35 36 #ifndef _MACHINE_PSL_H_ 37 #define _MACHINE_PSL_H_ 38 39 /* 40 * 386 processor status longword. 41 */ 42 #define PSL_C 0x00000001 /* carry bit */ 43 #define PSL_PF 0x00000004 /* parity bit */ 44 #define PSL_AF 0x00000010 /* bcd carry bit */ 45 #define PSL_Z 0x00000040 /* zero bit */ 46 #define PSL_N 0x00000080 /* negative bit */ 47 #define PSL_T 0x00000100 /* trace enable bit */ 48 #define PSL_I 0x00000200 /* interrupt enable bit */ 49 #define PSL_D 0x00000400 /* string instruction direction bit */ 50 #define PSL_V 0x00000800 /* overflow bit */ 51 #define PSL_IOPL 0x00003000 /* i/o privilege level */ 52 #define PSL_NT 0x00004000 /* nested task bit */ 53 #define PSL_RF 0x00010000 /* resume flag bit */ 54 #define PSL_VM 0x00020000 /* virtual 8086 mode bit */ 55 #define PSL_AC 0x00040000 /* alignment checking */ 56 #define PSL_VIF 0x00080000 /* virtual interrupt enable */ 57 #define PSL_VIP 0x00100000 /* virtual interrupt pending */ 58 #define PSL_ID 0x00200000 /* identification bit */ 59 60 /* 61 * The i486 manual says that we are not supposed to change reserved flags, 62 * but this is too much trouble since the reserved flags depend on the cpu 63 * and setting them to their historical values works in practice. 64 */ 65 #define PSL_RESERVED_DEFAULT 0x00000002 66 67 /* 68 * Initial flags for kernel and user mode. The kernel later inherits 69 * PSL_I and some other flags from user mode. 70 */ 71 #define PSL_KERNEL PSL_RESERVED_DEFAULT 72 #define PSL_USER (PSL_RESERVED_DEFAULT | PSL_I) 73 74 /* 75 * Bits that can be changed in user mode on 486's. We allow these bits 76 * to be changed using ptrace(), sigreturn() and procfs. Setting PS_NT 77 * is undesirable but it may as well be allowed since users can inflict 78 * it on the kernel directly. Changes to PSL_AC are silently ignored on 79 * 386's. 80 * 81 * Users are allowed to change the privileged flag PSL_RF. The cpu sets PSL_RF 82 * in tf_eflags for faults. Debuggers should sometimes set it there too. 83 * tf_eflags is kept in the signal context during signal handling and there is 84 * no other place to remember it, so the PSL_RF bit may be corrupted by the 85 * signal handler without us knowing. Corruption of the PSL_RF bit at worst 86 * causes one more or one less debugger trap, so allowing it is fairly 87 * harmless. 88 */ 89 #define PSL_USERCHANGE (PSL_C | PSL_PF | PSL_AF | PSL_Z | PSL_N | PSL_T \ 90 | PSL_D | PSL_V | PSL_NT | PSL_RF | PSL_AC | PSL_ID) 91 92 #endif /* !_MACHINE_PSL_H_ */ 93