xref: /freebsd/sys/dev/psci/smccc.c (revision cd0d51baaa4509a1db83251a601d34404d20c990)
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 __FBSDID("$FreeBSD$");
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 
42 #include <dev/psci/psci.h>
43 #include <dev/psci/smccc.h>
44 
45 #define	SMCCC_VERSION_1_0	0x10000
46 
47 /* Assume 1.0 until we detect a later version */
48 static uint32_t	smccc_version = SMCCC_VERSION_1_0;
49 
50 static void
51 smccc_init(void *dummy)
52 {
53 	int32_t features;
54 	uint32_t ret;
55 
56 	features = psci_features(SMCCC_VERSION);
57 	if (features != PSCI_RETVAL_NOT_SUPPORTED) {
58 		ret = psci_call(SMCCC_VERSION, 0, 0, 0);
59 		/* This should always be the case as we checked it above */
60 		if (ret > 0)
61 			smccc_version = ret;
62 	}
63 
64 	if (bootverbose) {
65 		printf("Found SMCCC version %u.%u\n",
66 		    SMCCC_VERSION_MAJOR(smccc_version),
67 		    SMCCC_VERSION_MINOR(smccc_version));
68 	}
69 }
70 SYSINIT(smccc_start, SI_SUB_CONFIGURE, SI_ORDER_ANY, smccc_init, NULL);
71 
72 int32_t
73 smccc_arch_features(uint32_t smccc_func_id)
74 {
75 
76 	if (smccc_version == SMCCC_VERSION_1_0)
77 		return (PSCI_RETVAL_NOT_SUPPORTED);
78 
79 	return (psci_call(SMCCC_ARCH_FEATURES, smccc_func_id, 0, 0));
80 }
81 
82 /*
83  * The SMCCC handler for Spectre variant 2: Branch target injection.
84  * (CVE-2017-5715)
85  */
86 int
87 smccc_arch_workaround_1(void)
88 {
89 
90 	KASSERT(smccc_version != SMCCC_VERSION_1_0,
91 	    ("SMCCC arch workaround 1 called with an invalid SMCCC interface"));
92 	return (psci_call(SMCCC_ARCH_WORKAROUND_1, 0, 0, 0));
93 }
94 
95 int
96 smccc_arch_workaround_2(int enable)
97 {
98 
99 	KASSERT(smccc_version != SMCCC_VERSION_1_0,
100 	    ("SMCCC arch workaround 2 called with an invalid SMCCC interface"));
101 	return (psci_call(SMCCC_ARCH_WORKAROUND_2, enable, 0, 0));
102 }
103