1/*-
 2 * SPDX-License-Identifier: BSD-2-Clause
 3 *
 4 * Copyright (c) 2021 The FreeBSD Foundation
 5 *
 6 * This software was developed by Mark Johnston under sponsorship from the
 7 * FreeBSD Foundation.
 8 *
 9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions are
11 * met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in
16 *    the documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#ifndef _MACHINE_MSAN_H_
32#define	_MACHINE_MSAN_H_
33
34#ifdef KMSAN
35
36#include <vm/vm.h>
37#include <vm/pmap.h>
38#include <vm/vm_page.h>
39#include <machine/vmparam.h>
40
41typedef uint32_t msan_orig_t;
42
43/*
44 * Our 32-bit origin cells encode a 2-bit type and 30-bit pointer to a kernel
45 * instruction.  The pointer is compressed by making it a positive offset
46 * relative to KERNBASE.
47 */
48#define	KMSAN_ORIG_TYPE_SHIFT	30u
49#define	KMSAN_ORIG_PTR_MASK	((1u << KMSAN_ORIG_TYPE_SHIFT) - 1)
50
51static inline msan_orig_t
52kmsan_md_orig_encode(int type, uintptr_t ptr)
53{
54	return ((type << KMSAN_ORIG_TYPE_SHIFT) |
55	    ((ptr & KMSAN_ORIG_PTR_MASK)));
56}
57
58static inline void
59kmsan_md_orig_decode(msan_orig_t orig, int *type, uintptr_t *ptr)
60{
61	*type = orig >> KMSAN_ORIG_TYPE_SHIFT;
62	*ptr = (orig & KMSAN_ORIG_PTR_MASK) | KERNBASE;
63}
64
65static inline vm_offset_t
66kmsan_md_addr_to_shad(vm_offset_t addr)
67{
68	return (addr - VM_MIN_KERNEL_ADDRESS + KMSAN_SHAD_MIN_ADDRESS);
69}
70
71static inline vm_offset_t
72kmsan_md_addr_to_orig(vm_offset_t addr)
73{
74	return (addr - VM_MIN_KERNEL_ADDRESS + KMSAN_ORIG_MIN_ADDRESS);
75}
76
77static inline bool
78kmsan_md_unsupported(vm_offset_t addr)
79{
80	/*
81	 * The kernel itself isn't shadowed: for most purposes global variables
82	 * are always initialized, and because KMSAN kernels are large
83	 * (GENERIC-KMSAN is ~80MB at the time of writing), shadowing would
84	 * incur signficant memory usage.
85	 */
86	return (addr < VM_MIN_KERNEL_ADDRESS || addr >= KERNBASE);
87}
88
89#endif /* KMSAN */
90
91#endif /* !_MACHINE_MSAN_H_ */