xref: /freebsd/sys/dev/psci/smccc.c (revision ae477ca7da55f76d28859e1bd01cd1051e36f28f)
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/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 
39 #include <dev/psci/psci.h>
40 #include <dev/psci/smccc.h>
41 
42 #define	SMCCC_VERSION_1_0	0x10000
43 
44 /* Assume 1.0 until we detect a later version */
45 static uint32_t	smccc_version;
46 
47 void
48 smccc_init(void)
49 {
50 	int32_t features;
51 	uint32_t ret;
52 
53 	smccc_version = SMCCC_VERSION_1_0;
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 	MPASS(smccc_version != 0);
73 	return (smccc_version);
74 }
75 
76 int32_t
77 smccc_arch_features(uint32_t smccc_func_id)
78 {
79 
80 	MPASS(smccc_version != 0);
81 	if (smccc_version == SMCCC_VERSION_1_0)
82 		return (PSCI_RETVAL_NOT_SUPPORTED);
83 
84 	return (psci_call(SMCCC_ARCH_FEATURES, smccc_func_id, 0, 0));
85 }
86 
87 /*
88  * The SMCCC handler for Spectre variant 2: Branch target injection.
89  * (CVE-2017-5715)
90  */
91 int
92 smccc_arch_workaround_1(void)
93 {
94 
95 	MPASS(smccc_version != 0);
96 	KASSERT(smccc_version != SMCCC_VERSION_1_0,
97 	    ("SMCCC arch workaround 1 called with an invalid SMCCC interface"));
98 	return (psci_call(SMCCC_ARCH_WORKAROUND_1, 0, 0, 0));
99 }
100 
101 int
102 smccc_arch_workaround_2(int enable)
103 {
104 
105 	MPASS(smccc_version != 0);
106 	KASSERT(smccc_version != SMCCC_VERSION_1_0,
107 	    ("SMCCC arch workaround 2 called with an invalid SMCCC interface"));
108 	return (psci_call(SMCCC_ARCH_WORKAROUND_2, enable, 0, 0));
109 }
110