Added the cache flushing before sending to C3 and fixing a stack mis-calculation

[kuqin12]

Preface

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Description

This change fixed an issue when suspending the BSP to C3, the returned context could be randomly corrupted, which was due to the core number calculation was incorrect, which made the BSP uses the beginning of allocated buffer as the stack bottom.

In the meantime, not flushing the cache makes the debugger not able to identify the memory write through stack pointer corruptions.

This change should fix both of them.

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• Impacts functionality?
  • Functionality - Does the change ultimately impact how firmware functions?
  • Examples: Add a new library, publish a new PPI, update an algorithm, ...
• Impacts security?
  • Security - Does the change have a direct security impact on an application,
    flow, or firmware?
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    validation improvement, ...
• Breaking change?
  • Breaking change - Will anyone consuming this change experience a break
    in build or boot behavior?
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    a function in a new library class in a pre-existing module, ...
• Includes tests?
  • Tests - Does the change include any explicit test code?
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• Includes documentation?
  • Documentation - Does the change contain explicit documentation additions
    outside direct code modifications (and comments)?
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How This Was Tested

This is verified on proprietary hardware platform.

Integration Instructions

N/A

[os-d]

Good find!