From 00b8bf7eda00fb6f0197d3968b6078cfdb4870fa Mon Sep 17 00:00:00 2001 From: "Cole, Deric" Date: Tue, 2 Jun 2020 06:32:25 +0800 Subject: UefiCpuPkg/SecCore: Add pre-memory AP vector 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. Reviewed-by: Eric Dong Reviewed-by: Ray Ni Cc: Laszlo Ersek Signed-off-by: Deric Cole --- UefiCpuPkg/SecCore/Ia32/ResetVec.nasmb | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-) (limited to 'UefiCpuPkg/SecCore') 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, -- cgit v1.2.3