1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2023-2025 Ruslan Bukin <br@bsdpad.com>
5 *
6 * This work was supported by Innovate UK project 105694, "Digital Security
7 * by Design (DSbD) Technology Platform Prototype".
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are 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 the
16 * 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 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/lock.h>
34 #include <sys/malloc.h>
35 #include <sys/mutex.h>
36 #include <sys/refcount.h>
37 #include <sys/hwt.h>
38
39 #include <dev/hwt/hwt_context.h>
40 #include <dev/hwt/hwt_contexthash.h>
41 #include <dev/hwt/hwt_config.h>
42
43 #define HWT_DEBUG
44 #undef HWT_DEBUG
45
46 #ifdef HWT_DEBUG
47 #define dprintf(fmt, ...) printf(fmt, ##__VA_ARGS__)
48 #else
49 #define dprintf(fmt, ...)
50 #endif
51
52 #define HWT_CONTEXTHASH_SIZE 1024
53
54 static MALLOC_DEFINE(M_HWT_CONTEXTHASH, "hwt_chash", "Hardware Trace");
55
56 /*
57 * Hash function. Discard the lower 2 bits of the pointer since
58 * these are always zero for our uses. The hash multiplier is
59 * round((2^LONG_BIT) * ((sqrt(5)-1)/2)).
60 */
61
62 #define _HWT_HM 11400714819323198486u /* hash multiplier */
63 #define HWT_HASH_PTR(P, M) ((((unsigned long) (P) >> 2) * _HWT_HM) & (M))
64
65 static struct mtx hwt_contexthash_mtx;
66 static u_long hwt_contexthashmask;
LIST_HEAD(hwt_contexthash,hwt_context)67 static LIST_HEAD(hwt_contexthash, hwt_context) *hwt_contexthash;
68
69 /*
70 * To use by hwt_switch_in/out() and hwt_record() only.
71 * This function returns with refcnt acquired.
72 */
73 struct hwt_context *
74 hwt_contexthash_lookup(struct proc *p)
75 {
76 struct hwt_contexthash *hch;
77 struct hwt_context *ctx;
78 int hindex;
79
80 hindex = HWT_HASH_PTR(p, hwt_contexthashmask);
81 hch = &hwt_contexthash[hindex];
82
83 HWT_CTXHASH_LOCK();
84 LIST_FOREACH(ctx, hch, next_hch) {
85 if (ctx->proc == p) {
86 refcount_acquire(&ctx->refcnt);
87 HWT_CTXHASH_UNLOCK();
88 return (ctx);
89 }
90 }
91 HWT_CTXHASH_UNLOCK();
92
93 return (NULL);
94 }
95
96 void
hwt_contexthash_insert(struct hwt_context * ctx)97 hwt_contexthash_insert(struct hwt_context *ctx)
98 {
99 struct hwt_contexthash *hch;
100 int hindex;
101
102 hindex = HWT_HASH_PTR(ctx->proc, hwt_contexthashmask);
103 hch = &hwt_contexthash[hindex];
104
105 HWT_CTXHASH_LOCK();
106 LIST_INSERT_HEAD(hch, ctx, next_hch);
107 HWT_CTXHASH_UNLOCK();
108 }
109
110 void
hwt_contexthash_remove(struct hwt_context * ctx)111 hwt_contexthash_remove(struct hwt_context *ctx)
112 {
113
114 HWT_CTXHASH_LOCK();
115 LIST_REMOVE(ctx, next_hch);
116 HWT_CTXHASH_UNLOCK();
117 }
118
119 void
hwt_contexthash_load(void)120 hwt_contexthash_load(void)
121 {
122
123 hwt_contexthash = hashinit(HWT_CONTEXTHASH_SIZE, M_HWT_CONTEXTHASH,
124 &hwt_contexthashmask);
125 mtx_init(&hwt_contexthash_mtx, "hwt ctx hash", "hwt ctx", MTX_SPIN);
126 }
127
128 void
hwt_contexthash_unload(void)129 hwt_contexthash_unload(void)
130 {
131
132 mtx_destroy(&hwt_contexthash_mtx);
133 hashdestroy(hwt_contexthash, M_HWT_CONTEXTHASH, hwt_contexthashmask);
134 }
135