1 /* $NetBSD: smccc.c,v 1.4 2023/11/07 13:31:26 rin Exp $ */
2
3 /*-
4 * Copyright (c) 2021 Jared McNeill <jmcneill@invisible.ca>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: smccc.c,v 1.4 2023/11/07 13:31:26 rin Exp $");
31
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34
35 #include <arm/arm/psci.h>
36 #include <arm/arm/smccc.h>
37
38 #if defined(__arm__)
39 # if defined(__clang__)
40 #define SMCCC_ARCH_ATTRIBUTE __attribute__ ((target("armv7ve")))
41 # else /* gcc */
42 #define SMCCC_ARCH_ATTRIBUTE __attribute__ ((target("arch=armv7ve")))
43 # endif
44 #else
45 #define SMCCC_ARCH_ATTRIBUTE
46 #endif
47
48 /* Minimum supported PSCI version for SMCCC discovery */
49 #define PSCI_VERSION_1_0 0x10000
50
51 /* Retrieve the implemented version of the SMC Calling Convention. */
52 #define SMCCC_VERSION 0x80000000
53
54 /* True if SMCCC is detected. */
55 static bool smccc_present;
56
57 /* SMCCC conduit (SMC or HVC) */
58 static enum psci_conduit smccc_conduit = PSCI_CONDUIT_NONE;
59
60 /*
61 * smccc_probe --
62 *
63 * Returns true if SMCCC is supported by platform firmware.
64 */
65 bool
smccc_probe(void)66 smccc_probe(void)
67 {
68 if (cold && !smccc_present) {
69 if (!psci_available() || psci_version() < PSCI_VERSION_1_0) {
70 return false;
71 }
72
73 smccc_present = psci_features(SMCCC_VERSION) == PSCI_SUCCESS;
74 if (smccc_present) {
75 smccc_conduit = psci_conduit();
76
77 aprint_debug("SMCCC: Version %#x (%s)\n",
78 smccc_version(),
79 smccc_conduit == PSCI_CONDUIT_SMC ? "SMC" : "HVC");
80 }
81 }
82 return smccc_present;
83 }
84
85 /*
86 * smccc_version --
87 *
88 * Return the implemented SMCCC version, or a negative error code on failure.
89 */
90 int
smccc_version(void)91 smccc_version(void)
92 {
93 return smccc_call(SMCCC_VERSION, 0, 0, 0, 0,
94 NULL, NULL, NULL, NULL);
95 }
96
97 /*
98 * smccc_call --
99 *
100 * Generic call interface for SMC/HVC calls.
101 */
102 SMCCC_ARCH_ATTRIBUTE int
smccc_call(uint32_t fid,register_t arg1,register_t arg2,register_t arg3,register_t arg4,register_t * res0,register_t * res1,register_t * res2,register_t * res3)103 smccc_call(uint32_t fid,
104 register_t arg1, register_t arg2, register_t arg3, register_t arg4,
105 register_t *res0, register_t *res1, register_t *res2, register_t *res3)
106 {
107 register_t args[5] = { fid, arg1, arg2, arg3, arg4 };
108
109 register register_t r0 asm ("r0");
110 register register_t r1 asm ("r1");
111 register register_t r2 asm ("r2");
112 register register_t r3 asm ("r3");
113 register register_t r4 asm ("r4");
114
115 if (!smccc_present) {
116 return SMCCC_NOT_SUPPORTED;
117 }
118
119 KASSERT(smccc_conduit != PSCI_CONDUIT_NONE);
120
121 r0 = args[0];
122 r1 = args[1];
123 r2 = args[2];
124 r3 = args[3];
125 r4 = args[4];
126
127 if (smccc_conduit == PSCI_CONDUIT_SMC) {
128 asm volatile ("smc #0" :
129 "=r" (r0), "=r" (r1), "=r" (r2), "=r" (r3) :
130 "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4) :
131 "memory");
132 } else {
133 asm volatile ("hvc #0" :
134 "=r" (r0), "=r" (r1), "=r" (r2), "=r" (r3) :
135 "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4) :
136 "memory");
137 }
138
139 if (res0) {
140 *res0 = r0;
141 }
142 if (res1) {
143 *res1 = r1;
144 }
145 if (res2) {
146 *res2 = r2;
147 }
148 if (res3) {
149 *res3 = r3;
150 }
151
152 return r0;
153 }
154