[edk2-staging][PATCH v4 1/2] EDK2 Code First: PI Specification: New error codes of Host Software class

["Kun Qin" <kuqin12@gmail.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3794

This change includes specification update markdown file that describes
the proposed PI Specification v1.7 Errata A in detail and potential
impact to the existing codebase.

Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>

Signed-off-by: Kun Qin <kuqin12@gmail.com>
---

Notes:
    v2:
    - Removed "RELEASE_ASSERT" definition
    - Removed reference to EDK2 based memory type info [Mike]
    
    v3:
    - No review, no change
    
    v4:
    - Updated draft status to "Accepted with modification"
    - Updated definition to "INCONSISTENT_MEMORY_MAP" [PIWG]

 CodeFirst/BZ3794-SpecChange.md | 55 ++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/CodeFirst/BZ3794-SpecChange.md b/CodeFirst/BZ3794-SpecChange.md
new file mode 100644
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+++ b/CodeFirst/BZ3794-SpecChange.md
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+# Title: Introduction of `EFI_SW_EC_INCONSISTENT_MEMORY_MAP` Status Code
+
+## Status: Accepted by industry standard forum with modifications
+
+## Document: UEFI Platform Initialization Specification Version 1.7 Errata A
+
+## License
+
+SPDX-License-Identifier: CC-BY-4.0
+
+## Submitter: [TianoCore Community](https://www.tianocore.org)
+
+## Summary of the change
+
+Add `EFI_SW_EC_INCONSISTENT_MEMORY_MAP` into Status Codes definition.
+
+## Benefits of the change
+
+Current Status Codes covered various [software class error code definitions](https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Pi/PiStatusCode.h).
+
+However, inconsistent memory map from boot to boot would fail to meet certain OS ACPI requirements (i.e. S4 resume boot requires consistent memory maps) and trigger system reboots. Yet the corresponding case was not covered by the already defined status codes.
+
+The unexpected system reboots above could indicate decay of system health and reporting of such generic events would provide helpful information to OEMs to investigate/prevent system failures in general.
+
+The request of this change intends to expand definitions of `EFI_SW_EC_**` under Status Codes to cover more unexpected system reboot events, which could improve Status Code futility and readability.
+
+## Impact of the change
+
+Occupy a new macro definitions of Error Codes under Software class Status Codes.
+
+## Detailed description of the change [normative updates]
+
+### Specification Changes
+
+1. In PI Specification v1.7 Errata A: Vol. 3, Table 3-61: Error Code Operations: Host Software Class, add one new rows below `EFI_SW_EC_FV_CORRUPTED` definition:
+
+    | Operation | Description | Extended Data |
+    | --- | --- | --- |
+    | EFI_SW_EC_INCONSISTENT_MEMORY_MAP | System will reboot due to inconsistent memory maps | None |
+
+1. In PI Specification v1.7 Errata A: Vol. 3, Table 3-61: Error Code Operations: Host Software Class, replace the row of `0x0014-0x00FF` to:
+
+    | Operation | Description | Extended Data |
+    | --- | --- | --- |
+    | 0x0015-0x00FF | Reserved for future use by this specification for Host Software class error codes. | None |
+
+1. In PI Specification v1.7 Errata A: Vol. 3, Section 6.7.4.3 Error Code Definitions: Prototype, add one new definitions below `EFI_SW_EC_FV_CORRUPTED` definition:
+
+    ```c
+    #define EFI_SW_EC_INCONSISTENT_MEMORY_MAP  0x00000014
+    ```
+
+### Code Changes
+
+1. Add macro definitions in `MdePkg/Include/Pi/PiStatusCode.h` to match new specification.
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