diff options
Diffstat (limited to 'MdePkg/Library/BaseRngLib/Rand/RdRand.c')
-rw-r--r-- | MdePkg/Library/BaseRngLib/Rand/RdRand.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseRngLib/Rand/RdRand.c b/MdePkg/Library/BaseRngLib/Rand/RdRand.c new file mode 100644 index 0000000000..09fb875ac3 --- /dev/null +++ b/MdePkg/Library/BaseRngLib/Rand/RdRand.c @@ -0,0 +1,131 @@ +/** @file
+ Random number generator services that uses RdRand instruction access
+ to provide high-quality random numbers.
+
+Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+#include "BaseRngLibInternals.h"
+
+//
+// Bit mask used to determine if RdRand instruction is supported.
+//
+#define RDRAND_MASK BIT30
+
+
+STATIC BOOLEAN mRdRandSupported;
+
+/**
+ The constructor function checks whether or not RDRAND instruction is supported
+ by the host hardware.
+
+ The constructor function checks whether or not RDRAND instruction is supported.
+ It will ASSERT() if RDRAND instruction is not supported.
+ It will always return EFI_SUCCESS.
+
+ @retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
+
+**/
+EFI_STATUS
+EFIAPI
+BaseRngLibConstructor (
+ VOID
+ )
+{
+ UINT32 RegEcx;
+
+ //
+ // Determine RDRAND support by examining bit 30 of the ECX register returned by
+ // CPUID. A value of 1 indicates that processor support RDRAND instruction.
+ //
+ AsmCpuid (1, 0, 0, &RegEcx, 0);
+ ASSERT ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
+
+ mRdRandSupported = ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
+
+ return EFI_SUCCESS;
+}
+
+/**
+ Generates a 16-bit random number.
+
+ @param[out] Rand Buffer pointer to store the 16-bit random value.
+
+ @retval TRUE Random number generated successfully.
+ @retval FALSE Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber16 (
+ OUT UINT16 *Rand
+ )
+{
+ return AsmRdRand16 (Rand);
+}
+
+/**
+ Generates a 32-bit random number.
+
+ @param[out] Rand Buffer pointer to store the 32-bit random value.
+
+ @retval TRUE Random number generated successfully.
+ @retval FALSE Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber32 (
+ OUT UINT32 *Rand
+ )
+{
+ return AsmRdRand32 (Rand);
+}
+
+/**
+ Generates a 64-bit random number.
+
+ @param[out] Rand Buffer pointer to store the 64-bit random value.
+
+ @retval TRUE Random number generated successfully.
+ @retval FALSE Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber64 (
+ OUT UINT64 *Rand
+ )
+{
+ return AsmRdRand64 (Rand);
+}
+
+/**
+ Checks whether RDRAND is supported.
+
+ @retval TRUE RDRAND is supported.
+ @retval FALSE RDRAND is not supported.
+
+**/
+BOOLEAN
+EFIAPI
+ArchIsRngSupported (
+ VOID
+ )
+{
+ /*
+ Existing software depends on this always returning TRUE, so for
+ now hard-code it.
+
+ return mRdRandSupported;
+ */
+ return TRUE;
+}
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