| 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 | |
| 35 | #ifndef _MACHINE_PSL_H_ |
| 36 | #define _MACHINE_PSL_H_ |
| 37 | |
| 38 | /* |
| 39 | * 386 processor status longword. |
| 40 | */ |
| 41 | #define PSL_C 0x00000001 /* carry bit */ |
| 42 | #define PSL_PF 0x00000004 /* parity bit */ |
| 43 | #define PSL_AF 0x00000010 /* bcd carry bit */ |
| 44 | #define PSL_Z 0x00000040 /* zero bit */ |
| 45 | #define PSL_N 0x00000080 /* negative bit */ |
| 46 | #define PSL_T 0x00000100 /* trace enable bit */ |
| 47 | #define PSL_I 0x00000200 /* interrupt enable bit */ |
| 48 | #define PSL_D 0x00000400 /* string instruction direction bit */ |
| 49 | #define PSL_V 0x00000800 /* overflow bit */ |
| 50 | #define PSL_IOPL 0x00003000 /* i/o privilege level */ |
| 51 | #define PSL_NT 0x00004000 /* nested task bit */ |
| 52 | #define PSL_RF 0x00010000 /* resume flag bit */ |
| 53 | #define PSL_VM 0x00020000 /* virtual 8086 mode bit */ |
| 54 | #define PSL_AC 0x00040000 /* alignment checking */ |
| 55 | #define PSL_VIF 0x00080000 /* virtual interrupt enable */ |
| 56 | #define PSL_VIP 0x00100000 /* virtual interrupt pending */ |
| 57 | #define PSL_ID 0x00200000 /* identification bit */ |
| 58 | |
| 59 | /* |
| 60 | * The i486 manual says that we are not supposed to change reserved flags, |
| 61 | * but this is too much trouble since the reserved flags depend on the cpu |
| 62 | * and setting them to their historical values works in practice. |
| 63 | */ |
| 64 | #define PSL_RESERVED_DEFAULT 0x00000002 |
| 65 | |
| 66 | /* |
| 67 | * Initial flags for kernel and user mode. The kernel later inherits |
| 68 | * PSL_I and some other flags from user mode. |
| 69 | */ |
| 70 | #define PSL_KERNEL PSL_RESERVED_DEFAULT |
| 71 | #define PSL_USER (PSL_RESERVED_DEFAULT | PSL_I) |
| 72 | |
| 73 | /* |
| 74 | * Bits that can be changed in user mode on 486's. We allow these bits |
| 75 | * to be changed using ptrace(), sigreturn() and procfs. Setting PS_NT |
| 76 | * is undesirable but it may as well be allowed since users can inflict |
| 77 | * it on the kernel directly. Changes to PSL_AC are silently ignored on |
| 78 | * 386's. |
| 79 | * |
| 80 | * Users are allowed to change the privileged flag PSL_RF. The cpu sets PSL_RF |
| 81 | * in tf_eflags for faults. Debuggers should sometimes set it there too. |
| 82 | * tf_eflags is kept in the signal context during signal handling and there is |
| 83 | * no other place to remember it, so the PSL_RF bit may be corrupted by the |
| 84 | * signal handler without us knowing. Corruption of the PSL_RF bit at worst |
| 85 | * causes one more or one less debugger trap, so allowing it is fairly |
| 86 | * harmless. |
| 87 | */ |
| 88 | #define PSL_USERCHANGE (PSL_C | PSL_PF | PSL_AF | PSL_Z | PSL_N | PSL_T \ |
| 89 | | PSL_D | PSL_V | PSL_NT | PSL_RF | PSL_AC | PSL_ID) |
| 90 | |
| 91 | #endif /* !_MACHINE_PSL_H_ */ |