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MdePkg/BaseRngLib: Remove global variable for RDRAND state update 

As a BASE type library, some PEI drivers could link and use it.
Tcg2Pei.inf is an example. On edk2-stable202408 version, PEI drivers
that link the library include the global variable of mRdRandSupported.
The previous commit (c3a8ca7) that refers to the global variable actually
is found to influence the link status. Updating the global variable
in PEI drivers could affect the following issues.

PEI ROM Boot : Global variable is not updated
PEI RAM Boot : PEI FV integration/security check is failed

To address these issues, remove the global variable usage.

Signed-off-by: Phil Noh <Phil.Noh@amd.com>
This commit is contained in:
Phil Noh 2024-11-21 10:05:01 -06:00 committed by mergify[bot]
parent 4d3cf37ff0
commit edb312d5d0
1 changed files with 17 additions and 20 deletions
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37
MdePkg/Library/BaseRngLib/Rand/RdRand.c
View File

@ -2,6 +2,7 @@
Random number generator services that uses RdRand instruction access Random number generator services that uses RdRand instruction access
to provide high-quality random numbers. to provide high-quality random numbers.
Copyright (C) 2024 Advanced Micro Devices, Inc. All rights reserved.<BR>
Copyright (c) 2023, Arm Limited. All rights reserved.<BR> Copyright (c) 2023, Arm Limited. All rights reserved.<BR>
Copyright (c) 2022, Pedro Falcato. All rights reserved.<BR> Copyright (c) 2022, Pedro Falcato. All rights reserved.<BR>
Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR> Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
@ -23,8 +24,6 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
// //
#define RDRAND_MASK BIT30 #define RDRAND_MASK BIT30
STATIC BOOLEAN mRdRandSupported;
// //
// Intel SDM says 10 tries is good enough for reliable RDRAND usage. // Intel SDM says 10 tries is good enough for reliable RDRAND usage.
// //
@ -124,20 +123,6 @@ BaseRngLibConstructor (
VOID 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);
mRdRandSupported = ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
if (mRdRandSupported) {
mRdRandSupported = TestRdRand ();
}
return EFI_SUCCESS; return EFI_SUCCESS;
} }
@ -156,7 +141,6 @@ ArchGetRandomNumber16 (
OUT UINT16 *Rand OUT UINT16 *Rand
) )
{ {
ASSERT (mRdRandSupported);
return AsmRdRand16 (Rand); return AsmRdRand16 (Rand);
} }
@ -175,7 +159,6 @@ ArchGetRandomNumber32 (
OUT UINT32 *Rand OUT UINT32 *Rand
) )
{ {
ASSERT (mRdRandSupported);
return AsmRdRand32 (Rand); return AsmRdRand32 (Rand);
} }
@ -194,7 +177,6 @@ ArchGetRandomNumber64 (
OUT UINT64 *Rand OUT UINT64 *Rand
) )
{ {
ASSERT (mRdRandSupported);
return AsmRdRand64 (Rand); return AsmRdRand64 (Rand);
} }
@ -211,7 +193,22 @@ ArchIsRngSupported (
VOID VOID
) )
{ {
return mRdRandSupported; BOOLEAN RdRandSupported;
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);
RdRandSupported = ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
if (RdRandSupported) {
RdRandSupported = TestRdRand ();
}
return RdRandSupported;
} }
/** /**