freebsd-skq/sys/arm64/include/undefined.h
andrew 54f410cc0e Add support for handling undefined instructions in userspace and the
kernel. We can register callbacks to perform the required operation on the
saved registers before returning.

This is initially used to work around a bug in old versions of QEMU that
trigger such an exception when reading from an ID register when it should
load z zero value.

I expect this could be used with other exception types, e.g. to emulate
special register access from userland.

Sponsored by:	DARPA, AFRL
2017-09-14 17:29:51 +00:00

45 lines
1.9 KiB
C

/*-
* Copyright (c) 2017 Andrew Turner
* All rights reserved.
*
* This software was developed by SRI International and the University of
* Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
* ("CTSRD"), as part of the DARPA CRASH research programme.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _MACHINE__UNDEFINED_H_
#define _MACHINE__UNDEFINED_H_
typedef int (*undef_handler_t)(vm_offset_t, uint32_t, struct trapframe *,
uint32_t);
void undef_init(void);
void *install_undef_handler(bool, undef_handler_t);
void remove_undef_handler(void *);
int undef_insn(u_int, struct trapframe *);
#endif