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
41 typedef 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
51 static inline msan_orig_t
kmsan_md_orig_encode(int type,uintptr_t ptr)52 kmsan_md_orig_encode(int type, uintptr_t ptr)
53 {
54 return ((type << KMSAN_ORIG_TYPE_SHIFT) |
55 ((ptr & KMSAN_ORIG_PTR_MASK)));
56 }
57
58 static inline void
kmsan_md_orig_decode(msan_orig_t orig,int * type,uintptr_t * ptr)59 kmsan_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
65 static inline vm_offset_t
kmsan_md_addr_to_shad(vm_offset_t addr)66 kmsan_md_addr_to_shad(vm_offset_t addr)
67 {
68 return (addr - VM_MIN_KERNEL_ADDRESS + KMSAN_SHAD_MIN_ADDRESS);
69 }
70
71 static inline vm_offset_t
kmsan_md_addr_to_orig(vm_offset_t addr)72 kmsan_md_addr_to_orig(vm_offset_t addr)
73 {
74 return (addr - VM_MIN_KERNEL_ADDRESS + KMSAN_ORIG_MIN_ADDRESS);
75 }
76
77 static inline bool
kmsan_md_unsupported(vm_offset_t addr)78 kmsan_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 significant memory usage.
85 */
86 return (addr < VM_MIN_KERNEL_ADDRESS || addr >= KERNBASE);
87 }
88
89 #endif /* KMSAN */
90
91 #endif /* !_MACHINE_MSAN_H_ */
92