1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2023 ARM Ltd.
4 */
5
6#include <linux/jump_label.h>
7#include <linux/memblock.h>
8#include <linux/psci.h>
9#include <linux/swiotlb.h>
10#include <linux/cc_platform.h>
11#include <linux/platform_device.h>
12
13#include <asm/io.h>
14#include <asm/mem_encrypt.h>
15#include <asm/rsi.h>
16
17static struct realm_config config;
18
19unsigned long prot_ns_shared;
20EXPORT_SYMBOL(prot_ns_shared);
21
22DEFINE_STATIC_KEY_FALSE_RO(rsi_present);
23EXPORT_SYMBOL(rsi_present);
24
25bool cc_platform_has(enum cc_attr attr)
26{
27 switch (attr) {
28 case CC_ATTR_MEM_ENCRYPT:
29 return is_realm_world();
30 default:
31 return false;
32 }
33}
34EXPORT_SYMBOL_GPL(cc_platform_has);
35
36static bool rsi_version_matches(void)
37{
38 unsigned long ver_lower, ver_higher;
39 unsigned long ret = rsi_request_version(RSI_ABI_VERSION,
40 &ver_lower,
41 &ver_higher);
42
43 if (ret == SMCCC_RET_NOT_SUPPORTED)
44 return false;
45
46 if (ret != RSI_SUCCESS) {
47 pr_err("RME: RMM doesn't support RSI version %lu.%lu. Supported range: %lu.%lu-%lu.%lu\n",
48 RSI_ABI_VERSION_MAJOR, RSI_ABI_VERSION_MINOR,
49 RSI_ABI_VERSION_GET_MAJOR(ver_lower),
50 RSI_ABI_VERSION_GET_MINOR(ver_lower),
51 RSI_ABI_VERSION_GET_MAJOR(ver_higher),
52 RSI_ABI_VERSION_GET_MINOR(ver_higher));
53 return false;
54 }
55
56 pr_info("RME: Using RSI version %lu.%lu\n",
57 RSI_ABI_VERSION_GET_MAJOR(ver_lower),
58 RSI_ABI_VERSION_GET_MINOR(ver_lower));
59
60 return true;
61}
62
63static void __init arm64_rsi_setup_memory(void)
64{
65 u64 i;
66 phys_addr_t start, end;
67
68 /*
69 * Iterate over the available memory ranges and convert the state to
70 * protected memory. We should take extra care to ensure that we DO NOT
71 * permit any "DESTROYED" pages to be converted to "RAM".
72 *
73 * panic() is used because if the attempt to switch the memory to
74 * protected has failed here, then future accesses to the memory are
75 * simply going to be reflected as a SEA (Synchronous External Abort)
76 * which we can't handle. Bailing out early prevents the guest limping
77 * on and dying later.
78 */
79 for_each_mem_range(i, &start, &end) {
80 if (rsi_set_memory_range_protected_safe(start, end)) {
81 panic(fmt: "Failed to set memory range to protected: %pa-%pa",
82 &start, &end);
83 }
84 }
85}
86
87bool __arm64_is_protected_mmio(phys_addr_t base, size_t size)
88{
89 enum ripas ripas;
90 phys_addr_t end, top;
91
92 /* Overflow ? */
93 if (WARN_ON(base + size <= base))
94 return false;
95
96 end = ALIGN(base + size, RSI_GRANULE_SIZE);
97 base = ALIGN_DOWN(base, RSI_GRANULE_SIZE);
98
99 while (base < end) {
100 if (WARN_ON(rsi_ipa_state_get(base, end, &ripas, &top)))
101 break;
102 if (WARN_ON(top <= base))
103 break;
104 if (ripas != RSI_RIPAS_DEV)
105 break;
106 base = top;
107 }
108
109 return base >= end;
110}
111EXPORT_SYMBOL(__arm64_is_protected_mmio);
112
113static int realm_ioremap_hook(phys_addr_t phys, size_t size, pgprot_t *prot)
114{
115 if (__arm64_is_protected_mmio(phys, size))
116 *prot = pgprot_encrypted(*prot);
117 else
118 *prot = pgprot_decrypted(*prot);
119
120 return 0;
121}
122
123void __init arm64_rsi_init(void)
124{
125 if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_SMC)
126 return;
127 if (!rsi_version_matches())
128 return;
129 if (WARN_ON(rsi_get_realm_config(&config)))
130 return;
131 prot_ns_shared = BIT(config.ipa_bits - 1);
132
133 if (arm64_ioremap_prot_hook_register(realm_ioremap_hook))
134 return;
135
136 if (realm_register_memory_enc_ops())
137 return;
138
139 arm64_rsi_setup_memory();
140
141 static_branch_enable(&rsi_present);
142}
143
144static struct platform_device rsi_dev = {
145 .name = RSI_PDEV_NAME,
146 .id = PLATFORM_DEVID_NONE
147};
148
149static int __init arm64_create_dummy_rsi_dev(void)
150{
151 if (is_realm_world() &&
152 platform_device_register(&rsi_dev))
153 pr_err("failed to register rsi platform device\n");
154 return 0;
155}
156
157arch_initcall(arm64_create_dummy_rsi_dev)
158

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source code of linux/arch/arm64/kernel/rsi.c