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MdePkg/BaseRngLib: Add support for ARMv8.5 RNG instructions

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Make BaseRngLib more generic by moving x86-specific functionality into
'Rand' and adding files under 'AArch64' to support the optional ARMv8.5
RNG instruction RNDR that is a part of FEAT_RNG.

Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
This commit is contained in:
Rebecca Cran
2021-05-10 15:53:07 -06:00
committed by mergify[bot]
parent ef3840c1ff
commit 9301e5644c
13 changed files with 602 additions and 55 deletions
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87
MdePkg/Library/BaseRngLib/BaseRng.c
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@@ -1,8 +1,10 @@
/** @file
Random number generator services that uses RdRand instruction access
to provide high-quality random numbers.
Random number generator services that uses CPU RNG instructions to
provide 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
**/
@@ -10,46 +12,15 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
//
// Bit mask used to determine if RdRand instruction is supported.
//
#define RDRAND_MASK BIT30
#include "BaseRngLibInternals.h"
//
// 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".
// Architectures Software Developer's Manual".
//
#define RDRAND_RETRY_LIMIT 10
#define GETRANDOM_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.
@@ -72,11 +43,19 @@ GetRandomNumber16 (
ASSERT (Rand != NULL);
if (Rand == NULL) {
return FALSE;
}
if (!ArchIsRngSupported ()) {
return FALSE;
}
//
// 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)) {
for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {
if (ArchGetRandomNumber16 (Rand)) {
return TRUE;
}
}
@@ -105,11 +84,19 @@ GetRandomNumber32 (
ASSERT (Rand != NULL);
if (Rand == NULL) {
return FALSE;
}
if (!ArchIsRngSupported ()) {
return FALSE;
}
//
// 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)) {
for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {
if (ArchGetRandomNumber32 (Rand)) {
return TRUE;
}
}
@@ -138,11 +125,19 @@ GetRandomNumber64 (
ASSERT (Rand != NULL);
if (Rand == NULL) {
return FALSE;
}
if (!ArchIsRngSupported ()) {
return FALSE;
}
//
// 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)) {
for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {
if (ArchGetRandomNumber64 (Rand)) {
return TRUE;
}
}
@@ -169,6 +164,14 @@ GetRandomNumber128 (
{
ASSERT (Rand != NULL);
if (Rand == NULL) {
return FALSE;
}
if (!ArchIsRngSupported ()) {
return FALSE;
}
//
// Read first 64 bits
//