| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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_ */ |