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UefiCpuPkg/ResetVector: Remove AP waking vector from ResetVector
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REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4494

Current reset vector uses 0xffffffe0 as AP waking vector, and expects
GenFv generates code aligned on a 4k boundary which will jump to this
location. However, some issues are listed below
1. GenFV doesn't generate code as the comment expects, because GenFv
assumes no modifications are required to the VTF-0 'Volume Top File'.
2. Even if removing VFT0 signature and let GenFv to modify, Genfv is
hard-code using another flash address 0xffffffd0.
3. In the same patch series, AP waking vector code is removed from
GenFv, because no such usage anymore. The existing of first two issues
also approve the usage is not available for a long time.

Therefore, remove AP waking vector related code.

Cc: Eric Dong <[email protected]>
Cc: Ray Ni <[email protected]>
Cc: Rahul Kumar <[email protected]>
Cc: Gerd Hoffmann <[email protected]>
Reviewed-by: Ray Ni <[email protected]>
Signed-off-by: Zhiguang Liu <[email protected]>
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LiuZhiguang001 authored and mergify[bot] committed Sep 18, 2023
1 parent dea6002 commit db38c7d
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Showing 2 changed files with 3 additions and 19 deletions.
7 changes: 0 additions & 7 deletions UefiCpuPkg/ResetVector/Vtf0/Ia16/Init16.asm
Original file line number Diff line number Diff line change
Expand Up @@ -17,13 +17,6 @@ EarlyBspInitReal16:
mov di, 'BP'
jmp short Main16

;
; @param[out] DI 'AP' to indicate application processor
;
EarlyApInitReal16:
mov di, 'AP'
jmp short Main16

;
; Modified: EAX
;
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15 changes: 3 additions & 12 deletions UefiCpuPkg/ResetVector/Vtf0/Ia16/ResetVectorVtf0.asm
Original file line number Diff line number Diff line change
Expand Up @@ -32,22 +32,13 @@ ALIGN 16
TIMES (0x1000 - 0x20) DB 0
%endif

applicationProcessorEntryPoint:
;
; Application Processors entry point
; 0xffffffe0
;
; GenFv generates code aligned on a 4k boundary which will jump to this
; location. (0xffffffe0) This allows the Local APIC Startup IPI to be
; used to wake up the application processors.
;
jmp EarlyApInitReal16

ALIGN 8

DD 0
DD 0, 0, 0

;
; The VTF signature
; The VTF signature (0xffffffec)
;
; VTF-0 means that the VTF (Volume Top File) code does not require
; any fixups.
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