projects / mirror_edk2.git / blame
| Commit | Line | Data |
|---|---|---|
| 3aa8dc6c LQ |
1 | /** @file\r |
| 2 | RDRAND Support Routines.\r | |
| 3 | \r | |
| 4 | Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>\r | |
| 5 | This program and the accompanying materials\r | |
| 6 | are licensed and made available under the terms and conditions of the BSD License\r | |
| 7 | which accompanies this distribution. The full text of the license may be found at\r | |
| 8 | http://opensource.org/licenses/bsd-license.php\r | |
| 9 | \r | |
| 10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
| 11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
| 12 | \r | |
| 13 | **/\r | |
| 14 | \r | |
| 15 | #include "RdRand.h"\r | |
| 16 | \r | |
| 17 | /**\r | |
| 18 | Generates a 64-bit random number through RDRAND instruction.\r | |
| 19 | \r | |
| 20 | @param[out] Rand Buffer pointer to store the random result.\r | |
| 21 | \r | |
| 22 | @retval TRUE RDRAND call was successful.\r | |
| 23 | @retval FALSE Failed attempts to call RDRAND.\r | |
| 24 | \r | |
| 25 | **/\r | |
| 26 | BOOLEAN\r | |
| 27 | EFIAPI\r | |
| 28 | RdRand64Step (\r | |
| 29 | OUT UINT64 *Rand\r | |
| 30 | )\r | |
| 31 | {\r | |
| 32 | UINT32 RandLow;\r | |
| 33 | UINT32 RandHigh;\r | |
| 34 | \r | |
| 35 | //\r | |
| 36 | // Generating a 64-bit rand on a 32-bit system by \r | |
| 37 | // mapping two 32-bit RDRAND instructions.\r | |
| 38 | //\r | |
| 39 | if (!RdRand32Step (&RandLow)) {\r | |
| 40 | return FALSE;\r | |
| 41 | }\r | |
| 42 | if (!RdRand32Step (&RandHigh)) {\r | |
| 43 | return FALSE;\r | |
| 44 | }\r | |
| 45 | \r | |
| 46 | *Rand = (UINT64) RandLow | LShiftU64 ((UINT64)RandHigh, 32);\r | |
| 47 | \r | |
| 48 | return TRUE;\r | |
| 49 | }\r | |
| 50 | \r | |
| 51 | /**\r | |
| 52 | Calls RDRAND to request a word-length random number.\r | |
| 53 | \r | |
| 54 | @param[out] Rand Buffer pointer to store the random number.\r | |
| 55 | @param[in] NeedRetry Determine whether or not to loop retry.\r | |
| 56 | \r | |
| 57 | @retval EFI_SUCCESS Random word generation succeeded.\r | |
| 58 | @retval EFI_NOT_READY Failed to request random word.\r | |
| 59 | \r | |
| 60 | **/\r | |
| 61 | EFI_STATUS\r | |
| 62 | EFIAPI\r | |
| 63 | RdRandWord (\r | |
| 64 | OUT UINTN *Rand,\r | |
| 65 | IN BOOLEAN NeedRetry\r | |
| 66 | )\r | |
| 67 | {\r | |
| 68 | return RdRand32 (Rand, NeedRetry);\r | |
| 69 | }\r | |
| 70 | \r | |
| 71 | /**\r | |
| 72 | Calls RDRAND to request multiple word-length random numbers.\r | |
| 73 | \r | |
| 74 | @param[in] Length Size of the buffer, in words, to fill with.\r | |
| 75 | @param[out] RandBuffer Pointer to the buffer to store the random result.\r | |
| 76 | \r | |
| 77 | @retval EFI_SUCCESS Random words generation succeeded.\r | |
| 78 | @retval EFI_NOT_READY Failed to request random words.\r | |
| 79 | \r | |
| 80 | **/\r | |
| 81 | EFI_STATUS\r | |
| 82 | EFIAPI\r | |
| 83 | RdRandGetWords (\r | |
| 84 | IN UINTN Length,\r | |
| 85 | OUT UINTN *RandBuffer\r | |
| 86 | )\r | |
| 87 | {\r | |
| 88 | EFI_STATUS Status;\r | |
| 89 | UINT32 Index;\r | |
| 90 | \r | |
| 91 | for (Index = 0; Index < Length; Index++) {\r | |
| 92 | //\r | |
| 93 | // Obtain one word-length (32-bit) Random Number with possible retry-loop.\r | |
| 94 | //\r | |
| 95 | Status = RdRand32 (RandBuffer, TRUE);\r | |
| 96 | if (EFI_ERROR (Status)) {\r | |
| 97 | return Status;\r | |
| 98 | }\r | |
| 99 | \r | |
| 100 | RandBuffer++;\r | |
| 101 | }\r | |
| 102 | \r | |
| 103 | return EFI_SUCCESS;\r | |
| 104 | }\r |