Rng.c File Reference

#include <Uefi.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/RngLib.h>
#include <Register/RiscV64/RiscVEncoding.h>
#include "BaseRngLibInternals.h"

Go to the source code of this file.

Macros
#define	RISCV_CPU_FEATURE_ZKR_BITMASK   0x8
#define	SEED_RETRY_LOOPS   100
#define	STATE_SIZE   312
#define	MIDDLE   156
#define	INIT_SHIFT   62
#define	TWIST_MASK   0xb5026f5aa96619e9ULL
#define	INIT_FACT   6364136223846793005ULL
#define	SHIFT1   29
#define	MASK1   0x5555555555555555ULL
#define	SHIFT2   17
#define	MASK2   0x71d67fffeda60000ULL
#define	SHIFT3   37
#define	MASK3   0xfff7eee000000000ULL
#define	SHIFT4   43
#define	LOWER_MASK   0x7fffffff
#define	UPPER_MASK   (~(UINT64)LOWER_MASK)

Functions
STATIC VOID	SeedRng (IN UINT64 S)
STATIC VOID	TwistRng (VOID)
UINT64	ReadSeed (VOID)
STATIC BOOLEAN	Get64BitSeed (OUT UINT64 *Out)
EFI_STATUS EFIAPI	BaseRngLibConstructor (VOID)
BOOLEAN EFIAPI	ArchGetRandomNumber16 (OUT UINT16 *Rand)
BOOLEAN EFIAPI	ArchGetRandomNumber32 (OUT UINT32 *Rand)
BOOLEAN EFIAPI	ArchGetRandomNumber64 (OUT UINT64 *Rand)
BOOLEAN EFIAPI	ArchIsRngSupported (VOID)

Detailed Description

Random number generator service that uses the SEED instruction to provide pseudorandom numbers.

Copyright (c) 2024, Rivos, Inc.

SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file Rng.c.

Macro Definition Documentation

INIT_FACT

#define INIT_FACT   6364136223846793005ULL

Definition at line 30 of file Rng.c.

INIT_SHIFT

#define INIT_SHIFT   62

Definition at line 28 of file Rng.c.

LOWER_MASK

#define LOWER_MASK   0x7fffffff

Definition at line 39 of file Rng.c.

MASK1

#define MASK1   0x5555555555555555ULL

Definition at line 32 of file Rng.c.

MASK2

#define MASK2   0x71d67fffeda60000ULL

Definition at line 34 of file Rng.c.

MASK3

#define MASK3   0xfff7eee000000000ULL

Definition at line 36 of file Rng.c.

MIDDLE

#define MIDDLE   156

Definition at line 27 of file Rng.c.

RISCV_CPU_FEATURE_ZKR_BITMASK

#define RISCV_CPU_FEATURE_ZKR_BITMASK   0x8

Definition at line 17 of file Rng.c.

SEED_RETRY_LOOPS

#define SEED_RETRY_LOOPS   100

Definition at line 19 of file Rng.c.

SHIFT1

#define SHIFT1   29

Definition at line 31 of file Rng.c.

SHIFT2

#define SHIFT2   17

Definition at line 33 of file Rng.c.

SHIFT3

#define SHIFT3   37

Definition at line 35 of file Rng.c.

SHIFT4

#define SHIFT4   43

Definition at line 37 of file Rng.c.

STATE_SIZE

#define STATE_SIZE   312

Definition at line 26 of file Rng.c.

TWIST_MASK

#define TWIST_MASK   0xb5026f5aa96619e9ULL

Definition at line 29 of file Rng.c.

UPPER_MASK

#define UPPER_MASK   (~(UINT64)LOWER_MASK)

Definition at line 40 of file Rng.c.

Function Documentation

ArchGetRandomNumber16()

BOOLEAN EFIAPI ArchGetRandomNumber16

(

OUT UINT16 *

Rand

)

Generates a 16-bit random number.

Parameters

[out]

Rand

Buffer pointer to store the 16-bit random value.

Return values

TRUE	Random number generated successfully.
FALSE	Failed to generate the random number.

Definition at line 187 of file Rng.c.

ArchGetRandomNumber32()

BOOLEAN EFIAPI ArchGetRandomNumber32

(

OUT UINT32 *

Rand

)

Generates a 32-bit random number.

Parameters

[out]

Rand

Buffer pointer to store the 32-bit random value.

Return values

TRUE	Random number generated successfully.
FALSE	Failed to generate the random number.

Definition at line 212 of file Rng.c.

ArchGetRandomNumber64()

BOOLEAN EFIAPI ArchGetRandomNumber64

(

OUT UINT64 *

Rand

)

Generates a 64-bit random number.

Parameters

[out]

Rand

Buffer pointer to store the 64-bit random value.

Return values

TRUE	Random number generated successfully.
FALSE	Failed to generate the random number.

Definition at line 237 of file Rng.c.

ArchIsRngSupported()

BOOLEAN EFIAPI ArchIsRngSupported

(

VOID

)

Checks whether SEED is supported.

Return values

TRUE	SEED is supported.

Definition at line 272 of file Rng.c.

BaseRngLibConstructor()

EFI_STATUS EFIAPI BaseRngLibConstructor

(

VOID

)

Constructor library which initializes Seeds and mStatus array.

Return values

EFI_SUCCESS	Intialization was successful.
EFI_UNSUPPORTED	Feature not supported.

Definition at line 162 of file Rng.c.

Get64BitSeed()

STATIC BOOLEAN Get64BitSeed

(

OUT UINT64 *

Out

)

Gets seed value by executing trng instruction (CSR 0x15) amd returns the see to the caller 64bit value.

Parameters

[out]

Out

Buffer pointer to store the 64-bit random value.

Return values

TRUE	Random number generated successfully.
FALSE	Failed to generate the random number.

Definition at line 107 of file Rng.c.

SeedRng()

STATIC VOID SeedRng

(

IN UINT64

S

)

Initialize mState to defualt state.

Parameters

[in]

S

Input seed value

Definition at line 52 of file Rng.c.

TwistRng()

STATIC VOID TwistRng

(

VOID

)

Initializes mState with entropy values. The initialization is based on the Seed value populated in mState[0] which then influences all the other values in the mState array. Later values are retrieved from the same array instead of calling trng instruction every time.

Definition at line 75 of file Rng.c.