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9301e564 RC |
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 | |
20 | STATIC BOOLEAN mRndrSupported;\r | |
21 | \r | |
22 | //\r | |
23 | // Bit mask used to determine if RNDR instruction is supported.\r | |
24 | //\r | |
25 | #define RNDR_MASK ((UINT64)MAX_UINT16 << 60U)\r | |
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 | |
44 | UINT64 Isar0;\r | |
45 | //\r | |
46 | // Determine RNDR support by examining bits 63:60 of the ISAR0 register returned by\r | |
47 | // MSR. A non-zero value indicates that the processor supports the RNDR instruction.\r | |
48 | //\r | |
49 | Isar0 = ArmReadIdIsar0 ();\r | |
50 | ASSERT ((Isar0 & RNDR_MASK) != 0);\r | |
51 | \r | |
52 | mRndrSupported = ((Isar0 & RNDR_MASK) != 0);\r | |
53 | \r | |
54 | return EFI_SUCCESS;\r | |
55 | }\r | |
56 | \r | |
57 | /**\r | |
58 | Generates a 16-bit random number.\r | |
59 | \r | |
60 | @param[out] Rand Buffer pointer to store the 16-bit random value.\r | |
61 | \r | |
62 | @retval TRUE Random number generated successfully.\r | |
63 | @retval FALSE Failed to generate the random number.\r | |
64 | \r | |
65 | **/\r | |
66 | BOOLEAN\r | |
67 | EFIAPI\r | |
68 | ArchGetRandomNumber16 (\r | |
69 | OUT UINT16 *Rand\r | |
70 | )\r | |
71 | {\r | |
72 | UINT64 Rand64;\r | |
73 | \r | |
74 | if (ArchGetRandomNumber64 (&Rand64)) {\r | |
75 | *Rand = Rand64 & MAX_UINT16;\r | |
76 | return TRUE;\r | |
77 | }\r | |
78 | \r | |
79 | return FALSE;\r | |
80 | }\r | |
81 | \r | |
82 | /**\r | |
83 | Generates a 32-bit random number.\r | |
84 | \r | |
85 | @param[out] Rand Buffer pointer to store the 32-bit random value.\r | |
86 | \r | |
87 | @retval TRUE Random number generated successfully.\r | |
88 | @retval FALSE Failed to generate the random number.\r | |
89 | \r | |
90 | **/\r | |
91 | BOOLEAN\r | |
92 | EFIAPI\r | |
93 | ArchGetRandomNumber32 (\r | |
94 | OUT UINT32 *Rand\r | |
95 | )\r | |
96 | {\r | |
97 | UINT64 Rand64;\r | |
98 | \r | |
99 | if (ArchGetRandomNumber64 (&Rand64)) {\r | |
100 | *Rand = Rand64 & MAX_UINT32;\r | |
101 | return TRUE;\r | |
102 | }\r | |
103 | \r | |
104 | return FALSE;\r | |
105 | }\r | |
106 | \r | |
107 | /**\r | |
108 | Generates a 64-bit random number.\r | |
109 | \r | |
110 | @param[out] Rand Buffer pointer to store the 64-bit random value.\r | |
111 | \r | |
112 | @retval TRUE Random number generated successfully.\r | |
113 | @retval FALSE Failed to generate the random number.\r | |
114 | \r | |
115 | **/\r | |
116 | BOOLEAN\r | |
117 | EFIAPI\r | |
118 | ArchGetRandomNumber64 (\r | |
119 | OUT UINT64 *Rand\r | |
120 | )\r | |
121 | {\r | |
122 | return ArmRndr (Rand);\r | |
123 | }\r | |
124 | \r | |
125 | /**\r | |
126 | Checks whether RNDR is supported.\r | |
127 | \r | |
128 | @retval TRUE RNDR is supported.\r | |
129 | @retval FALSE RNDR is not supported.\r | |
130 | \r | |
131 | **/\r | |
132 | BOOLEAN\r | |
133 | EFIAPI\r | |
134 | ArchIsRngSupported (\r | |
135 | VOID\r | |
136 | )\r | |
137 | {\r | |
138 | return mRndrSupported;\r | |
139 | }\r |