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 signficant memory usage. 85 */ 86 return (addr < VM_MIN_KERNEL_ADDRESS || addr >= KERNBASE); 87 } 88 89 #endif /* KMSAN */ 90 91 #endif /* !_MACHINE_MSAN_H_ */ 92