mirror of https://github.com/acidanthera/audk.git
105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
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/** @file
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RDRAND Support Routines.
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Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "RdRand.h"
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/**
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Generates a 64-bit random number through RDRAND instruction.
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@param[out] Rand Buffer pointer to store the random result.
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@retval TRUE RDRAND call was successful.
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@retval FALSE Failed attempts to call RDRAND.
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**/
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BOOLEAN
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EFIAPI
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RdRand64Step (
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OUT UINT64 *Rand
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)
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{
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UINT32 RandLow;
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UINT32 RandHigh;
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//
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// Generating a 64-bit rand on a 32-bit system by
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// mapping two 32-bit RDRAND instructions.
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//
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if (!RdRand32Step (&RandLow)) {
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return FALSE;
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}
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if (!RdRand32Step (&RandHigh)) {
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return FALSE;
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}
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*Rand = (UINT64) RandLow | LShiftU64 ((UINT64)RandHigh, 32);
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return TRUE;
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}
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/**
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Calls RDRAND to request a word-length random number.
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@param[out] Rand Buffer pointer to store the random number.
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@param[in] NeedRetry Determine whether or not to loop retry.
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@retval EFI_SUCCESS Random word generation succeeded.
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@retval EFI_NOT_READY Failed to request random word.
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**/
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EFI_STATUS
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EFIAPI
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RdRandWord (
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OUT UINTN *Rand,
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IN BOOLEAN NeedRetry
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)
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{
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return RdRand32 (Rand, NeedRetry);
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}
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/**
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Calls RDRAND to request multiple word-length random numbers.
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@param[in] Length Size of the buffer, in words, to fill with.
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@param[out] RandBuffer Pointer to the buffer to store the random result.
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@retval EFI_SUCCESS Random words generation succeeded.
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@retval EFI_NOT_READY Failed to request random words.
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**/
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EFI_STATUS
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EFIAPI
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RdRandGetWords (
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IN UINTN Length,
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OUT UINTN *RandBuffer
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)
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{
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EFI_STATUS Status;
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UINT32 Index;
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for (Index = 0; Index < Length; Index++) {
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//
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// Obtain one word-length (32-bit) Random Number with possible retry-loop.
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//
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Status = RdRand32 (RandBuffer, TRUE);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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RandBuffer++;
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}
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return EFI_SUCCESS;
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}
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