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attempted to check for insecure and fatal eflags and segment selectors, but missed many cases and got the IOPL check back to front. The other syscalls didn't check at all. sys_process.c, machdep.c: Only allow PT_WRITE_U to write to the registers (ordinary and FP). psl.h, locore.s, machdep.c: Eliminate PSL_MBZ, PSL_MBO and PSL_USERCLR. We are not supposed to assume anything about the reserved bits. Use PSL_USERCHANGE and PSL_KERNEL instead. Rename PSL_USERSET to PSL_USER. exception.s: Define a private label for use by doreti when returning to user mode fails. machdep.c: In syscalls, allow changing only the eflags that can be changed on 486's in user mode (no longer attempt to allow benign IOPL changes; allow changing the nasty PSL_NT; don't allow changing the i586 bits). Don't attempt to check all the cases involving invalid selectors and %eip's. Just check for privilege violations and let the invalid things cause a trap. procfs_machdep.c: Call the ptrace register functions to do all the work for reading and writing ordinary registers and for single stepping. trap.c: Ignore traps caused by PSL_NT being set. Previously, users could cause a fatal trap in user mode by setting PSL_NT and executing an iret, and a fatal trap in kernel mode by setting PSL_NT and making a syscall. PSL_NT was cleared too late and not in enough modes to fix the problem. Make all traps in user mode (except T_NMI) nonfatal. Recover from traps caused by attempting to load invalid user registers in doreti by restarting the traps so that they appear to occur in user mode. --- Fix bogons that I noticed while fixing the above: psl.h: Fix some comments. Uniformize idempotency ifdef. exception.s, machdep.c: Remove rsvd[0-14]. rsvd0 hasn't been reserved since the 486 came out. Replace rsvd0 by `align'. rsvd[0-11] used wrong (magic non-unique) trap numbers. Replace rsvd[1-14] by rsvd. locore.s: Enable alignment check flag on 486's and 586's. machdep.c: Use a better type for kstack[]. Use TFREGP() to find the registers. Reformat ptrace functions from SEF to something closer to KNF. procfs_machdep.c: The wrong pointer to the registers got fixed as a side effect. Implement reading and writing of FP registers. /proc/*/*regs now work (only) for processes that are in memory. Clean up comments. trap.c, trap.h: Remove unused trap types.
89 lines
3.8 KiB
C
89 lines
3.8 KiB
C
/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* William Jolitz.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)psl.h 5.2 (Berkeley) 1/18/91
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* $Id: psl.h,v 1.5 1994/08/10 03:51:18 wollman Exp $
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*/
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#ifndef _MACHINE_PSL_H_
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#define _MACHINE_PSL_H_
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/*
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* 386 processor status longword.
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*/
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#define PSL_C 0x00000001 /* carry bit */
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#define PSL_PF 0x00000004 /* parity bit */
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#define PSL_AF 0x00000010 /* bcd carry bit */
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#define PSL_Z 0x00000040 /* zero bit */
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#define PSL_N 0x00000080 /* negative bit */
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#define PSL_T 0x00000100 /* trace enable bit */
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#define PSL_I 0x00000200 /* interrupt enable bit */
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#define PSL_D 0x00000400 /* string instruction direction bit */
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#define PSL_V 0x00000800 /* overflow bit */
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#define PSL_IOPL 0x00003000 /* i/o privilege level */
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#define PSL_NT 0x00004000 /* nested task bit */
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#define PSL_RF 0x00010000 /* resume flag bit */
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#define PSL_VM 0x00020000 /* virtual 8086 mode bit */
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#define PSL_AC 0x00040000 /* alignment checking */
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#define PSL_VIF 0x00080000 /* virtual interrupt enable */
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#define PSL_VIP 0x00100000 /* virtual interrupt pending */
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#define PSL_ID 0x00200000 /* identification bit */
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/*
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* The i486 manual says that we are not supposed to change reserved flags,
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* but this is too much trouble since the reserved flags depend on the cpu
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* and setting them to their historical values works in practice.
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*/
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#define PSL_RESERVED_DEFAULT 0x00000002
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/*
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* Initial flags for kernel and user mode. The kernel later inherits
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* PSL_I and some other flags from user mode.
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*/
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#define PSL_KERNEL PSL_RESERVED_DEFAULT
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#define PSL_USER (PSL_RESERVED_DEFAULT | PSL_I)
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/*
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* Bits that can be changed in user mode on 486's. We allow these bits
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* to be changed using ptrace(), sigreturn() and procfs. Setting PS_NT
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* is undesireable but it may as well be allowed since users can inflict
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* it on the kernel directly. Changes to PSL_AC are silently ignored on
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* 386's.
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*/
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#define PSL_USERCHANGE (PSL_C | PSL_PF | PSL_AF | PSL_Z | PSL_N | PSL_T \
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| PSL_D | PSL_V | PSL_NT | PSL_AC)
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#endif /* !_MACHINE_PSL_H_ */
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