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1 | /** @file\r |
2 | Random number generator service that uses the RNDR instruction\r | |
3 | to provide pseudorandom numbers.\r | |
4 | \r | |
5 | Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>\r | |
6 | Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>\r | |
7 | \r | |
8 | SPDX-License-Identifier: BSD-2-Clause-Patent\r | |
9 | \r | |
10 | **/\r | |
11 | \r | |
12 | #include <Uefi.h>\r | |
13 | #include <Library/BaseLib.h>\r | |
14 | #include <Library/DebugLib.h>\r | |
15 | #include <Library/RngLib.h>\r | |
16 | \r | |
17 | #include "ArmRng.h"\r | |
18 | #include "BaseRngLibInternals.h"\r | |
19 | \r | |
2f88bd3a | 20 | STATIC BOOLEAN mRndrSupported;\r |
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21 | \r |
22 | //\r | |
23 | // Bit mask used to determine if RNDR instruction is supported.\r | |
24 | //\r | |
2f88bd3a | 25 | #define RNDR_MASK ((UINT64)MAX_UINT16 << 60U)\r |
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26 | \r |
27 | /**\r | |
28 | The constructor function checks whether or not RNDR instruction is supported\r | |
29 | by the host hardware.\r | |
30 | \r | |
31 | The constructor function checks whether or not RNDR instruction is supported.\r | |
32 | It will ASSERT() if RNDR instruction is not supported.\r | |
33 | It will always return EFI_SUCCESS.\r | |
34 | \r | |
35 | @retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.\r | |
36 | \r | |
37 | **/\r | |
38 | EFI_STATUS\r | |
39 | EFIAPI\r | |
40 | BaseRngLibConstructor (\r | |
41 | VOID\r | |
42 | )\r | |
43 | {\r | |
2f88bd3a MK |
44 | UINT64 Isar0;\r |
45 | \r | |
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46 | //\r |
47 | // Determine RNDR support by examining bits 63:60 of the ISAR0 register returned by\r | |
48 | // MSR. A non-zero value indicates that the processor supports the RNDR instruction.\r | |
49 | //\r | |
50 | Isar0 = ArmReadIdIsar0 ();\r | |
51 | ASSERT ((Isar0 & RNDR_MASK) != 0);\r | |
52 | \r | |
53 | mRndrSupported = ((Isar0 & RNDR_MASK) != 0);\r | |
54 | \r | |
55 | return EFI_SUCCESS;\r | |
56 | }\r | |
57 | \r | |
58 | /**\r | |
59 | Generates a 16-bit random number.\r | |
60 | \r | |
61 | @param[out] Rand Buffer pointer to store the 16-bit random value.\r | |
62 | \r | |
63 | @retval TRUE Random number generated successfully.\r | |
64 | @retval FALSE Failed to generate the random number.\r | |
65 | \r | |
66 | **/\r | |
67 | BOOLEAN\r | |
68 | EFIAPI\r | |
69 | ArchGetRandomNumber16 (\r | |
2f88bd3a | 70 | OUT UINT16 *Rand\r |
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71 | )\r |
72 | {\r | |
2f88bd3a | 73 | UINT64 Rand64;\r |
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74 | \r |
75 | if (ArchGetRandomNumber64 (&Rand64)) {\r | |
76 | *Rand = Rand64 & MAX_UINT16;\r | |
77 | return TRUE;\r | |
78 | }\r | |
79 | \r | |
80 | return FALSE;\r | |
81 | }\r | |
82 | \r | |
83 | /**\r | |
84 | Generates a 32-bit random number.\r | |
85 | \r | |
86 | @param[out] Rand Buffer pointer to store the 32-bit random value.\r | |
87 | \r | |
88 | @retval TRUE Random number generated successfully.\r | |
89 | @retval FALSE Failed to generate the random number.\r | |
90 | \r | |
91 | **/\r | |
92 | BOOLEAN\r | |
93 | EFIAPI\r | |
94 | ArchGetRandomNumber32 (\r | |
2f88bd3a | 95 | OUT UINT32 *Rand\r |
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96 | )\r |
97 | {\r | |
2f88bd3a | 98 | UINT64 Rand64;\r |
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99 | \r |
100 | if (ArchGetRandomNumber64 (&Rand64)) {\r | |
101 | *Rand = Rand64 & MAX_UINT32;\r | |
102 | return TRUE;\r | |
103 | }\r | |
104 | \r | |
105 | return FALSE;\r | |
106 | }\r | |
107 | \r | |
108 | /**\r | |
109 | Generates a 64-bit random number.\r | |
110 | \r | |
111 | @param[out] Rand Buffer pointer to store the 64-bit random value.\r | |
112 | \r | |
113 | @retval TRUE Random number generated successfully.\r | |
114 | @retval FALSE Failed to generate the random number.\r | |
115 | \r | |
116 | **/\r | |
117 | BOOLEAN\r | |
118 | EFIAPI\r | |
119 | ArchGetRandomNumber64 (\r | |
2f88bd3a | 120 | OUT UINT64 *Rand\r |
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121 | )\r |
122 | {\r | |
123 | return ArmRndr (Rand);\r | |
124 | }\r | |
125 | \r | |
126 | /**\r | |
127 | Checks whether RNDR is supported.\r | |
128 | \r | |
129 | @retval TRUE RNDR is supported.\r | |
130 | @retval FALSE RNDR is not supported.\r | |
131 | \r | |
132 | **/\r | |
133 | BOOLEAN\r | |
134 | EFIAPI\r | |
135 | ArchIsRngSupported (\r | |
136 | VOID\r | |
137 | )\r | |
138 | {\r | |
139 | return mRndrSupported;\r | |
140 | }\r |