[PATCH v4 0/2] SecurityPkg: Fixes for RngDxe

["PierreGondois" <pierre.gondois@arm.com>]

From: Pierre Gondois <pierre.gondois@arm.com>

v1:
- https://edk2.groups.io/g/devel/message/96356
v2:
- https://edk2.groups.io/g/devel/message/96434
- Reformulate commit message.
- Do not warn if no algorithm is found as the message
  would be printed on non-Arm platforms.
v3:
- https://edk2.groups.io/g/devel/topic/95240503
- Add the following patches:
  1. ArmPkg/ArmTrngLib: Remove ASSERTs in ArmTrngLibConstructor()
     Requested by Ard.
     Cf https://edk2.groups.io/g/devel/message/96495
  2. SecurityPkg/RngDxe: Conditionally install EFI_RNG_PROTOCOL
     Do not install EFI_RNG_PROTOCOL if no RNG algorithm is available.
     Cf. https://edk2.groups.io/g/devel/message/96494
  3. SecurityPkg/RngDxe: Fix Rng algo selection for Arm
     Coming from v2 patch being split.
v4:
- Change description of:
   'SecurityPkg/RngDxe: Fix Rng algo selection for Arm'
  to:
   'SecurityPkg/RngDxe: Simplify Rng algorithm selection for Arm'
- Add patch:
    'SecurityPkg/RngDxe: Check for NULL PcdCpuRngSupportedAlgorithm'
- Remove as merged:
    SecurityPkg/RngDxe: Conditionally install EFI_RNG_PROTOCOL
    SecurityPkg/RngDxe: Correctly update mAvailableAlgoArrayCount

When adding support for the Firmware Trng interface, it was made
available through in the RngDxe module. In RngDxe, the algorithm
associated with PcdCpuRngSupportedAlgorithm (implemented by the
RngLib) was always advertised by default.

It was assumed that support for RngLib and RNDR instructions
should be kept in ArmVirtPkg. However this support did not exist
as all ArmVirtPkg use the BaseRngLibTimerLib.inf implementation
of the RngLib.

Do not advertise the RngLib and PcdCpuRngSupportedAlgorithm
if PcdCpuRngSupportedAlgorithm is NULL.

Also simplify the selection of the default algorithm.

Pierre Gondois (2):
  SecurityPkg/RngDxe: Simplify Rng algorithm selection for Arm
  SecurityPkg/RngDxe: Check for NULL PcdCpuRngSupportedAlgorithm

 .../RngDxe/AArch64/AArch64Algo.c                | 14 +++-----------
 .../RandomNumberGenerator/RngDxe/ArmRngDxe.c    | 17 ++++-------------
 2 files changed, 7 insertions(+), 24 deletions(-)

-- 
2.25.1