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2026-03-09IntelFsp2Pkg: Save/restore FSBASE/GSBASE in entry and exitRay Ni1-0/+25
FSP may store something in FSBASE/GSBASE while bootloader may do so as well. Add the FSBASE/GSBASE save/restore logic in the FSP entry and exit to avoid the contents in FSBASE/GSBASE are corrupted by the other party. The change assumes there is no very old CPU that does not support rdfsbase/wrfsbase/rdgsbase/wrgsbase instructions. Signed-off-by: Ray Ni <ray.ni@intel.com>
2025-07-18IntelFsp2Pkg: Preserve GDTR and CS/DS/ES/FS/GS/SSRay Ni1-1/+40
Bootloader does not expect FSP modifies GDTR and segment selectors, update FSP entry/exit code to preserve these registers. Signed-off-by: Ray Ni <ray.ni@intel.com> Cc: Chasel Chiu <chasel.chiu@intel.com> Cc: Nate DeSimone <nathaniel.l.desimone@intel.com> Cc: Star Zeng <star.zeng@intel.com> Cc: Ted Kuo <ted.kuo@intel.com> Cc: Ashraf Ali S <ashraf.ali.s@intel.com>
2024-09-11IntelFsp2Pkg: Support FSP API to save and restore page tableZhiguang Liu1-1/+108
A potential issue may happen when FSP creates/changes page table while bootloader doesn't expect page table being changed in FSP. Current, FSP API support to save/restore stack, IDT and general purpose registers. Following the same pattern, add save/restore page table support to solve this issue. Note that this feature only impacts FSP API mode, and is controlled by PCD PcdFspSaveRestorePageTableEnable. For compatibility, the PCD default value is set as FALSE. Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
2023-11-03IntelFsp2Pkg/SwitchStack: Reserve 32B when calling C function in 64bitNi, Ray1-1/+3
When FSP runs in API mode, it saves the IDTR in its own stack then switches to bootloader's stack before it returns from FspMemoryInit. Next time when the bootloader calls TempRamExit, FSP switches to its own stack and restores IDTR from its stack saved earlier. However, due to a bug in BaseFspSwitchStackLib, the IDTR saved on FSP's stack might be corrupted that results the following TempRamExit call fails inside FSP due to PeiServices pointer cannot be retrieved from IDT.base - 8. The bug is the assembly code doesn't reserve 32 bytes before calling the C routine in 64bit. According to the x86-64 calling convention, caller is responsible for allocating 32 bytes of "shadow space" on the stack right before calling the function (regardless of the actual number of parameters used). When FSP is built in optimization-off mode, the C routine makes use of the 32-byte "shadow space" which is not reserved by the assembly caller. That causes the IDTR saved on the stack is corrupted by the C routine. The patch fixes so by reserving the 32 bytes before calling C routine. Signed-off-by: Ray Ni <ray.ni@intel.com> Cc: Chasel Chiu <chasel.chiu@intel.com> Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com> Cc: Duggapu Chinni B <chinni.b.duggapu@intel.com> Cc: Ray Han Lim Ng <ray.han.lim.ng@intel.com> Cc: Star Zeng <star.zeng@intel.com> Reviewed-by: Ted Kuo <ted.kuo@intel.com> Reviewed-by: Ashraf Ali S <ashraf.ali.s@intel.com> Cc: Susovan Mohapatra <susovan.mohapatra@intel.com>
2022-04-16IntelFsp2Pkg: FspSecCore support for X64Ted Kuo1-2/+3
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3893 1.Added FspSecCore support for X64. 2.Bumped FSP header revision to 7 to indicate FSP 64bit is supported. 3.Corrected few typos. Cc: Chasel Chiu <chasel.chiu@intel.com> Cc: Nate DeSimone <nathaniel.l.desimone@intel.com> Cc: Star Zeng <star.zeng@intel.com> Cc: Ashraf Ali S <ashraf.ali.s@intel.com> Signed-off-by: Ted Kuo <ted.kuo@intel.com> Reviewed-by: Chasel Chiu <chasel.chiu@intel.com> Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>
2022-03-17IntelFsp2Pkg: BaseFspSwitchStackLib Support for X64Kuo, Ted1-0/+72
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3832 Add BaseFspSwitchStackLib Support for X64. Cc: Chasel Chiu <chasel.chiu@intel.com> Cc: Nate DeSimone <nathaniel.l.desimone@intel.com> Cc: Star Zeng <star.zeng@intel.com> Cc: Ashraf Ali S <ashraf.ali.s@intel.com> Signed-off-by: Ted Kuo <ted.kuo@intel.com> Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>