mirror of https://github.com/acidanthera/audk.git
141 lines
2.9 KiB
C
141 lines
2.9 KiB
C
/** @file
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Random number generator service that uses the RNDR instruction
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to provide pseudorandom numbers.
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Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
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Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Uefi.h>
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/RngLib.h>
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#include "ArmRng.h"
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#include "BaseRngLibInternals.h"
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STATIC BOOLEAN mRndrSupported;
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//
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// Bit mask used to determine if RNDR instruction is supported.
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//
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#define RNDR_MASK ((UINT64)MAX_UINT16 << 60U)
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/**
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The constructor function checks whether or not RNDR instruction is supported
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by the host hardware.
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The constructor function checks whether or not RNDR instruction is supported.
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It will ASSERT() if RNDR instruction is not supported.
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It will always return EFI_SUCCESS.
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@retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
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**/
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EFI_STATUS
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EFIAPI
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BaseRngLibConstructor (
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VOID
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)
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{
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UINT64 Isar0;
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//
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// Determine RNDR support by examining bits 63:60 of the ISAR0 register returned by
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// MSR. A non-zero value indicates that the processor supports the RNDR instruction.
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//
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Isar0 = ArmReadIdIsar0 ();
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ASSERT ((Isar0 & RNDR_MASK) != 0);
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mRndrSupported = ((Isar0 & RNDR_MASK) != 0);
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return EFI_SUCCESS;
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}
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/**
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Generates a 16-bit random number.
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@param[out] Rand Buffer pointer to store the 16-bit random value.
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@retval TRUE Random number generated successfully.
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@retval FALSE Failed to generate the random number.
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**/
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BOOLEAN
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EFIAPI
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ArchGetRandomNumber16 (
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OUT UINT16 *Rand
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)
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{
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UINT64 Rand64;
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if (ArchGetRandomNumber64 (&Rand64)) {
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*Rand = Rand64 & MAX_UINT16;
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return TRUE;
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}
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return FALSE;
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}
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/**
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Generates a 32-bit random number.
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@param[out] Rand Buffer pointer to store the 32-bit random value.
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@retval TRUE Random number generated successfully.
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@retval FALSE Failed to generate the random number.
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**/
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BOOLEAN
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EFIAPI
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ArchGetRandomNumber32 (
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OUT UINT32 *Rand
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)
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{
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UINT64 Rand64;
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if (ArchGetRandomNumber64 (&Rand64)) {
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*Rand = Rand64 & MAX_UINT32;
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return TRUE;
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}
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return FALSE;
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}
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/**
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Generates a 64-bit random number.
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@param[out] Rand Buffer pointer to store the 64-bit random value.
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@retval TRUE Random number generated successfully.
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@retval FALSE Failed to generate the random number.
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**/
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BOOLEAN
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EFIAPI
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ArchGetRandomNumber64 (
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OUT UINT64 *Rand
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)
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{
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return ArmRndr (Rand);
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}
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/**
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Checks whether RNDR is supported.
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@retval TRUE RNDR is supported.
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@retval FALSE RNDR is not supported.
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**/
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BOOLEAN
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EFIAPI
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ArchIsRngSupported (
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VOID
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)
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{
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return mRndrSupported;
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}
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