ArmPkg: Remove Deprecated ArmPsciResetSystemLib

[os-d]

Description

ArmPsciResetSystemLib has been deprecated since commit b2c55e732888fd721f5235a820b1d1c45209992d in 2017. The lib itself has not been meaningfully updated in 10 years. This commit removes the library to complete the deprecation process and remove confusion over which library to use for resetting an ARM platform.

• [x] Breaking change?
  • Breaking change - Does this PR cause a break in build or boot behavior?
  • Examples: Does it add a new library class or move a module to a different repo.
• [ ] Impacts security?
  • Security - Does this PR have a direct security impact?
  • Examples: Crypto algorithm change or buffer overflow fix.
• [ ] Includes tests?
  • Tests - Does this PR include any explicit test code?
  • Examples: Unit tests or integration tests.

How This Was Tested

N/A.

Integration Instructions

All platforms should be using ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.inf instead of this ancient library. If a platform was using the old library, they will experience a build break and will need to update to the current library.

[os-d]

@ardbiesheuvel @leiflindholm @samimujawar can you please review?

[ardbiesheuvel]

I suspect this will break the Ampere and Phytium builds in edk2-platforms.

@leiflindholm ?

[os-d]

@ardbiesheuvel, looks like nothing in those platforms is using EfiResetSystemLib, I suspect it is not actually needed and they can just use the ArmSmcPsciResetSystemLib? The Ampere one is already using it for non-runtime DXE.

[ardbiesheuvel]

@ardbiesheuvel, looks like nothing in those platforms is using EfiResetSystemLib, I suspect it is not actually needed and they can just use the ArmSmcPsciResetSystemLib? The Ampere one is already using it for non-runtime DXE.

Those platforms use EmbeddedPkg/ResetRuntimeDxe/ResetRuntimeDxe.inf and provide ArmPkg/Library/ArmPsciResetSystemLib/ArmPsciResetSystemLib.inf as the library class resolution for EfiResetSystemLib.

[os-d]

@ardbiesheuvel, looks like nothing in those platforms is using EfiResetSystemLib, I suspect it is not actually needed and they can just use the ArmSmcPsciResetSystemLib? The Ampere one is already using it for non-runtime DXE.

Those platforms use EmbeddedPkg/ResetRuntimeDxe/ResetRuntimeDxe.inf and provide ArmPkg/Library/ArmPsciResetSystemLib/ArmPsciResetSystemLib.inf as the library class resolution for EfiResetSystemLib.

Do you think it is valid for them to use ArmSmcPsciResetSystemLib.inf instead? I'm keying off your deprecation statement :). Or do you still envision ArmPsciResetSystemLib.inf as valid to use?

[leiflindholm]

Pinged platform maintainers/reviewers in https://edk2.groups.io/g/devel/topic/remove_deprecated/107432712.

I note RPi also uses EmbeddedPkg/ResetRuntimeDxe although has its own implementation of EfiResetSystemLib.

[ardbiesheuvel]

Pinged platform maintainers/reviewers in https://edk2.groups.io/g/devel/topic/remove_deprecated/107432712.

I note RPi also uses EmbeddedPkg/ResetRuntimeDxe although has its own implementation of EfiResetSystemLib.

Yeah. EmbeddedPkg/ResetRuntimeDxe should be deprecated and removed too.

I will also note that we could get rid of ArmVirtPkg/Library/ArmVirtPsciResetSystemLib as well if the generic ARM version of ResetSystemLib (which is called ArmVirtPkg/Library/ArmVirtPsciResetSystemLib and uses SMC exclusively) is refactored to depend on ArmMonitorLib (of which ArmVirtPkg has an implementation that encapsulates the logic that required us to provide its own special implementation of ResetSystemLib)

[leiflindholm]

I will also note that we could get rid of ArmVirtPkg/Library/ArmVirtPsciResetSystemLib as well if the generic ARM version of ResetSystemLib (which is called ArmVirtPkg/Library/ArmVirtPsciResetSystemLib and uses SMC exclusively) is refactored to depend on ArmMonitorLib (of which ArmVirtPkg has an implementation that encapsulates the logic that required us to provide its own special implementation of ResetSystemLib)

I like that idea.

[os-d]

@ardbiesheuvel, I don't have enough context to do the ArmVirtPkg refactor, but I can also remove EmbeddedPkg/ResetRuntimeDxe in this PR, too, if you want.

[ardbiesheuvel]

@ardbiesheuvel, I don't have enough context to do the ArmVirtPkg refactor, but I can also remove EmbeddedPkg/ResetRuntimeDxe in this PR, too, if you want.

I've sent out a series to remove the existing references to ArmPsciResetSystemLib from edk2-platforms. With that applied, we can merge this PR.

I'd like to repurpose the 'ArmPsciResetSystemLib' name to implement ResetSystemLib based on ArmMonitorLib, which would allow us to drop ArmVirtPsciResetSystemLib as I suggested, so I'll wait for this PR to get merged first.

EmbeddedPkg/RuntimeDxe can be dropped once RaspberryPi moves to MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystemRuntimeDxe.inf. This requires some more elaborate refactoring as RPi's EfiResetSystemLib has its own implementation of reset notifiers, which need to be accommodated elsewhere. This is something I can look into as well.