diff options
Diffstat (limited to 'Core/MdePkg/Library/BaseRngLib/BaseRng.c')
| -rw-r--r-- | Core/MdePkg/Library/BaseRngLib/BaseRng.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseRngLib/BaseRng.c b/Core/MdePkg/Library/BaseRngLib/BaseRng.c new file mode 100644 index 0000000000..2c8df56286 --- /dev/null +++ b/Core/MdePkg/Library/BaseRngLib/BaseRng.c @@ -0,0 +1,189 @@ +/** @file
+ Random number generator services that uses RdRand instruction access
+ to provide high-quality random numbers.
+
+Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution. The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+//
+// Bit mask used to determine if RdRand instruction is supported.
+//
+#define RDRAND_MASK BIT30
+
+//
+// Limited retry number when valid random data is returned.
+// Uses the recommended value defined in Section 7.3.17 of "Intel 64 and IA-32
+// Architectures Software Developer's Mannual".
+//
+#define RDRAND_RETRY_LIMIT 10
+
+/**
+ 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 RETURN_SUCCESS.
+
+ @retval RETURN_SUCCESS The constructor always returns EFI_SUCCESS.
+
+**/
+RETURN_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);
+
+ return RETURN_SUCCESS;
+}
+
+/**
+ Generates a 16-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @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
+GetRandomNumber16 (
+ OUT UINT16 *Rand
+ )
+{
+ UINT32 Index;
+
+ ASSERT (Rand != NULL);
+
+ //
+ // A loop to fetch a 16 bit random value with a retry count limit.
+ //
+ for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
+ if (AsmRdRand16 (Rand)) {
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+/**
+ Generates a 32-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @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
+GetRandomNumber32 (
+ OUT UINT32 *Rand
+ )
+{
+ UINT32 Index;
+
+ ASSERT (Rand != NULL);
+
+ //
+ // A loop to fetch a 32 bit random value with a retry count limit.
+ //
+ for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
+ if (AsmRdRand32 (Rand)) {
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+/**
+ Generates a 64-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @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
+GetRandomNumber64 (
+ OUT UINT64 *Rand
+ )
+{
+ UINT32 Index;
+
+ ASSERT (Rand != NULL);
+
+ //
+ // A loop to fetch a 64 bit random value with a retry count limit.
+ //
+ for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
+ if (AsmRdRand64 (Rand)) {
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+/**
+ Generates a 128-bit random number.
+
+ if Rand is NULL, then ASSERT().
+
+ @param[out] Rand Buffer pointer to store the 128-bit random value.
+
+ @retval TRUE Random number generated successfully.
+ @retval FALSE Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+GetRandomNumber128 (
+ OUT UINT64 *Rand
+ )
+{
+ ASSERT (Rand != NULL);
+
+ //
+ // Read first 64 bits
+ //
+ if (!GetRandomNumber64 (Rand)) {
+ return FALSE;
+ }
+
+ //
+ // Read second 64 bits
+ //
+ return GetRandomNumber64 (++Rand);
+}
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