REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2776
Add a vector at 0xFF000 (0xFFFFF000) that can be used by Init-SIPI-SIPI
to start an AP before memory is initialized. This vector jumps into the
same SEC entry point as the ordinary reset vector, with a special value
of "AP" in the DI register. The platform-specific SEC code is expected
to check for that value and take a different path for APs, if this
feature is supported by the platform.
Cc: Eric Dong <eric.d...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Laszlo Ersek <ler...@redhat.com>
Signed-off-by: Deric Cole <deric.c...@intel.com>
---
UefiCpuPkg/SecCore/Ia32/ResetVec.nasmb | 31 ++++++++++++++++++++++++-------
1 file changed, 24 insertions(+), 7 deletions(-)
diff --git a/UefiCpuPkg/SecCore/Ia32/ResetVec.nasmb
b/UefiCpuPkg/SecCore/Ia32/ResetVec.nasmb
index f41b9669d0..1dfc4efe4c 100644
--- a/UefiCpuPkg/SecCore/Ia32/ResetVec.nasmb
+++ b/UefiCpuPkg/SecCore/Ia32/ResetVec.nasmb
@@ -10,7 +10,7 @@
; Abstract:
;
; Reset Vector Data structure
-; This structure is located at 0xFFFFFFC0
+; This structure is located at 0xFFFFF000
;
;------------------------------------------------------------------------------
@@ -23,19 +23,36 @@ USE16
;
ORG 0h
+
+;
+; 0xFFFFF000
+;
+; We enter here with CS:IP = 0xFF00:0x0000. Do a far-jump to change CS to
0xF000
+; and IP to ApStartup.
+;
+ApVector:
+ mov di, "AP"
+ jmp 0xF000:0xF000+ApStartup
+
+ TIMES 0xFC0-($-$$) nop
+
+;
+; This should be at 0xFFFFFFC0
+;
+
;
; Reserved
;
ReservedData: DD 0eeeeeeeeh, 0eeeeeeeeh
- TIMES 0x10-($-$$) DB 0
+ TIMES 0xFD0-($-$$) nop
;
-; This is located at 0xFFFFFFD0h
+; This is located at 0xFFFFFFD0
;
mov di, "PA"
jmp ApStartup
- TIMES 0x20-($-$$) DB 0
+ TIMES 0xFE0-($-$$) nop
;
; Pointer to the entry point of the PEI core
; It is located at 0xFFFFFFE0, and is fixed up by some build tool
@@ -53,7 +70,7 @@ ASM_PFX(InterruptHandler):
jmp $
iret
- TIMES 0x30-($-$$) DB 0
+ TIMES 0xFF0-($-$$) nop
;
; For IA32, the reset vector must be at 0xFFFFFFF0, i.e., 4G-16 byte
; Execution starts here upon power-on/platform-reset.
@@ -74,7 +91,7 @@ ApStartup:
DW -3
- TIMES 0x38-($-$$) DB 0
+ TIMES 0xFF8-($-$$) nop
;
; Ap reset vector segment address is at 0xFFFFFFF8
; This will be fixed up by some build tool,
@@ -83,7 +100,7 @@ ApStartup:
;
ApSegAddress: dd 12345678h
- TIMES 0x3c-($-$$) DB 0
+ TIMES 0xFFC-($-$$) nop
;
; BFV Base is at 0xFFFFFFFC
; This will be fixed up by some build tool,
--
2.26.2.windows.1
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