Re: [edk2-devel] 回复: [PATCH 2/3] MdePkg: Refactor BaseRngLib to support AARCH64 in addition to X86

["Rebecca Cran" <rebecca@nuviainc.com>]

On 4/28/21 7:10 PM, gaoliming wrote:
> Rebecca:
> 
>> -----邮件原件-----
>> 发件人: Rebecca Cran <rebecca@nuviainc.com>
>> 发送时间: 2021年4月29日 4:44
>> 收件人: devel@edk2.groups.io
>> 抄送: Rebecca Cran <rebecca@nuviainc.com>; Jiewen Yao
>> <jiewen.yao@intel.com>; Jian J Wang <jian.j.wang@intel.com>; Michael D
>> Kinney <michael.d.kinney@intel.com>; Liming Gao
>> <gaoliming@byosoft.com.cn>; Zhiguang Liu <zhiguang.liu@intel.com>; Ard
>> Biesheuvel <ardb+tianocore@kernel.org>; Sami Mujawar
>> <Sami.Mujawar@arm.com>
>> 主题: [PATCH 2/3] MdePkg: Refactor BaseRngLib to support AARCH64 in
>> addition to X86
>>
>> Make BaseRngLib more generic by moving x86 specific functionality from
>> BaseRng.c into Rand/RdRand.c, and adding AArch64/Rndr.c, which supports
>> the optional ARMv8.5 RNG instructions RNDR and RNDRRS that are a part of
>> FEAT_RNG.
>>
>> Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
>> ---
>>   MdePkg/MdePkg.dec                               |   9 +-
>>   MdePkg/MdePkg.dsc                               |   4 +-
>>   MdePkg/Library/BaseRngLib/BaseRngLib.inf        |  16 ++-
>>   MdePkg/Library/BaseRngLib/BaseRngLibInternals.h |  31 +++++
>>   MdePkg/Library/BaseRngLib/AArch64/Rndr.c        | 121
>> ++++++++++++++++++++
>>   MdePkg/Library/BaseRngLib/BaseRng.c             |  55 +++------
>>   MdePkg/Library/BaseRngLib/Rand/RdRand.c         | 103
>> +++++++++++++++++
>>   MdePkg/Library/BaseRngLib/BaseRngLib.uni        |   6 +-
>>   8 files changed, 291 insertions(+), 54 deletions(-)
>>
>> diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
>> index 8965e903e093..b49f88d8e18f 100644
>> --- a/MdePkg/MdePkg.dec
>> +++ b/MdePkg/MdePkg.dec
>> @@ -267,6 +267,11 @@ [LibraryClasses]
>>     #
>>     RegisterFilterLib|Include/Library/RegisterFilterLib.h
>>
>> +[LibraryClasses.IA32, LibraryClasses.X64, LibraryClasses.AARCH64]
>> +  ##  @libraryclass  Provides services to generate random number.
>> +  #
>> +  RngLib|Include/Library/RngLib.h
>> +
>>   [LibraryClasses.IA32, LibraryClasses.X64]
>>     ##  @libraryclass  Abstracts both S/W SMI generation and detection.
>>     ##
>> @@ -288,10 +293,6 @@ [LibraryClasses.IA32, LibraryClasses.X64]
>>     #
>>     SmmPeriodicSmiLib|Include/Library/SmmPeriodicSmiLib.h
>>
>> -  ##  @libraryclass  Provides services to generate random number.
>> -  #
>> -  RngLib|Include/Library/RngLib.h
>> -
>>     ##  @libraryclass  Provides services to log the SMI handler
> registration.
>>     SmiHandlerProfileLib|Include/Library/SmiHandlerProfileLib.h
>>
>> diff --git a/MdePkg/MdePkg.dsc b/MdePkg/MdePkg.dsc
>> index d363419006ea..a94959169b2f 100644
>> --- a/MdePkg/MdePkg.dsc
>> +++ b/MdePkg/MdePkg.dsc
>> @@ -145,6 +145,9 @@ [Components.IA32, Components.X64,
>> Components.ARM, Components.AARCH64]
>>
>> MdePkg/Test/UnitTest/Library/BaseSafeIntLib/TestBaseSafeIntLibSmm.inf
>>
>> MdePkg/Test/UnitTest/Library/BaseSafeIntLib/TestBaseSafeIntLibUefiShell.in
>> f
>>
>> +[Components.IA32, Components.X64, Components.AARCH64]
>> +  MdePkg/Library/BaseRngLib/BaseRngLib.inf
>> +
>>   [Components.IA32, Components.X64]
>>     MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsic.inf
>>     MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsicSev.inf
>> @@ -168,7 +171,6 @@ [Components.IA32, Components.X64]
>>     MdePkg/Library/BaseS3StallLib/BaseS3StallLib.inf
>>     MdePkg/Library/SmmMemLib/SmmMemLib.inf
>>     MdePkg/Library/SmmIoLib/SmmIoLib.inf
>> -  MdePkg/Library/BaseRngLib/BaseRngLib.inf
>>     MdePkg/Library/SmmPciExpressLib/SmmPciExpressLib.inf
>>     MdePkg/Library/SmiHandlerProfileLibNull/SmiHandlerProfileLibNull.inf
>>     MdePkg/Library/MmServicesTableLib/MmServicesTableLib.inf
>> diff --git a/MdePkg/Library/BaseRngLib/BaseRngLib.inf
>> b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
>> index 31740751c69c..1dc3249a8c20 100644
>> --- a/MdePkg/Library/BaseRngLib/BaseRngLib.inf
>> +++ b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
>> @@ -1,9 +1,10 @@
>>   ## @file
>>   #  Instance of RNG (Random Number Generator) Library.
>>   #
>> -#  BaseRng Library that uses CPU RdRand instruction access to provide
>> -#  high-quality random numbers.
>> +#  BaseRng Library that uses CPU RNG instructions (e.g. RdRand) to
>> +#  provide high-quality random numbers.
>>   #
>> +#  Copyright (c) 2020, NUVIA Inc. All rights reserved.<BR>
>>   #  Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
>>   #
>>   #  SPDX-License-Identifier: BSD-2-Clause-Patent
>> @@ -22,11 +23,18 @@ [Defines]
>>     CONSTRUCTOR                    = BaseRngLibConstructor
>>
>>   #
>> -#  VALID_ARCHITECTURES           = IA32 X64
>> +#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
>>   #
>>
>> -[Sources.Ia32, Sources.X64]
>> +[Sources]
>>     BaseRng.c
>> +  BaseRngLibInternals.h
>> +
>> +[Sources.Ia32, Sources.X64]
>> +  Rand/RdRand.c
>> +
>> +[Sources.AARCH64]
>> +  AArch64/Rndr.c
>>
>>   [Packages]
>>     MdePkg/MdePkg.dec
>> diff --git a/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h
>> b/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h
>> new file mode 100644
>> index 000000000000..44fda69c9eec
>> --- /dev/null
>> +++ b/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h
>> @@ -0,0 +1,31 @@
>> +/** @file
>> +
>> +  Architecture specific interface to RNG functionality.
>> +
>> +Copyright (c) 2020, NUVIA Inc. All rights reserved.<BR>
>> +
>> +SPDX-License-Identifier: BSD-2-Clause-Patent
>> +
>> +**/
>> +
>> +#ifndef BASE_RNGLIB_INTERNALS_H_
>> +
>> +BOOLEAN
>> +EFIAPI
>> +ArchGetRandomNumber16 (
>> +  OUT UINT16 *Rand
>> +  );
>> +
>> +BOOLEAN
>> +EFIAPI
>> +ArchGetRandomNumber32 (
>> +  OUT UINT32 *Rand
>> +  );
>> +
>> +BOOLEAN
>> +EFIAPI
>> +ArchGetRandomNumber64 (
>> +  OUT UINT64 *Rand
>> +  );
>> +
>> +#endif    // BASE_RNGLIB_INTERNALS_H_
>> diff --git a/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
>> b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
>> new file mode 100644
>> index 000000000000..19643237923a
>> --- /dev/null
>> +++ b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
>> @@ -0,0 +1,121 @@
>> +/** @file
>> +  Random number generator service that uses the RNDR instruction
>> +  to provide high-quality random numbers.
>> +
>> +  Copyright (c) 2020, NUVIA Inc. All rights reserved.<BR>
>> +  Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
>> +
>> +  SPDX-License-Identifier: BSD-2-Clause-Patent
>> +
>> +**/
>> +
>> +#include <Library/BaseLib.h>
>> +#include <Library/DebugLib.h>
>> +
>> +#include <Library/RngLib.h>
>> +
>> +#include "BaseRngLibInternals.h"
>> +
>> +//
>> +// Bit mask used to determine if RNDR instruction is supported.
>> +//
>> +#define RNDR_MASK                  ((UINT64)MAX_UINT16 << 60U)
>> +
>> +/**
>> +  The constructor function checks whether or not RNDR instruction is
>> supported
>> +  by the host hardware.
>> +
>> +  The constructor function checks whether or not RNDR instruction is
>> supported.
>> +  It will ASSERT() if RNDR instruction is not supported.
>> +  It will always return RETURN_SUCCESS.
>> +
>> +  @retval RETURN_SUCCESS   The constructor always returns
>> EFI_SUCCESS.
>> +
>> +**/
>> +RETURN_STATUS
>> +EFIAPI
>> +BaseRngLibConstructor (
>> +  VOID
>> +  )
>> +{
>> +  UINT64 Isar0;
>> +  //
>> +  // Determine RNDR support by examining bits 63:60 of the ISAR0 register
>> returned by
>> +  // MSR. A non-zero value indicates that the processor supports the RNDR
>> instruction.
>> +  //
>> +  Isar0 = ArmReadIdIsar0 ();
>> +  ASSERT ((Isar0 & RNDR_MASK) != 0);
>> +  (void)Isar0;
>> +
> 
> What behavior for this statement "(void)Isar0;"?

It causes Isar0 to be 'used' in builds where ASSERT is compiled out, 
avoiding a warning/error.

-- 
Rebecca Cran