xref: /freebsd/sys/dev/psci/smccc.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2018 Andrew Turner
5  *
6  * This software was developed by SRI International and the University of
7  * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
8  * ("CTSRD"), as part of the DARPA CRASH research programme.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include "opt_acpi.h"
33 #include "opt_platform.h"
34 
35 #include <sys/cdefs.h>
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
39 
40 #include <dev/psci/psci.h>
41 #include <dev/psci/smccc.h>
42 
43 #define	SMCCC_VERSION_1_0	0x10000
44 
45 /* Assume 1.0 until we detect a later version */
46 static uint32_t	smccc_version = SMCCC_VERSION_1_0;
47 
48 void
49 smccc_init(void)
50 {
51 	int32_t features;
52 	uint32_t ret;
53 
54 	features = psci_features(SMCCC_VERSION);
55 	if (features != PSCI_RETVAL_NOT_SUPPORTED) {
56 		ret = psci_call(SMCCC_VERSION, 0, 0, 0);
57 		/* This should always be the case as we checked it above */
58 		if (ret > 0)
59 			smccc_version = ret;
60 	}
61 
62 	if (bootverbose) {
63 		printf("Found SMCCC version %u.%u\n",
64 		    SMCCC_VERSION_MAJOR(smccc_version),
65 		    SMCCC_VERSION_MINOR(smccc_version));
66 	}
67 }
68 
69 uint32_t
70 smccc_get_version(void)
71 {
72 	return (smccc_version);
73 }
74 
75 int32_t
76 smccc_arch_features(uint32_t smccc_func_id)
77 {
78 
79 	if (smccc_version == SMCCC_VERSION_1_0)
80 		return (PSCI_RETVAL_NOT_SUPPORTED);
81 
82 	return (psci_call(SMCCC_ARCH_FEATURES, smccc_func_id, 0, 0));
83 }
84 
85 /*
86  * The SMCCC handler for Spectre variant 2: Branch target injection.
87  * (CVE-2017-5715)
88  */
89 int
90 smccc_arch_workaround_1(void)
91 {
92 
93 	KASSERT(smccc_version != SMCCC_VERSION_1_0,
94 	    ("SMCCC arch workaround 1 called with an invalid SMCCC interface"));
95 	return (psci_call(SMCCC_ARCH_WORKAROUND_1, 0, 0, 0));
96 }
97 
98 int
99 smccc_arch_workaround_2(int enable)
100 {
101 
102 	KASSERT(smccc_version != SMCCC_VERSION_1_0,
103 	    ("SMCCC arch workaround 2 called with an invalid SMCCC interface"));
104 	return (psci_call(SMCCC_ARCH_WORKAROUND_2, enable, 0, 0));
105 }
106