For the case 32bit PEI + 64Bit DXE, we need to load 64bit IDT table to capture exceptions happened in long mode because 32bit IDT table cannot work in long mode. For the case 32bit PEI + 32bit DXE, we could use the 32bit IDT table setup in SEC/PEI and needn't to load new 32bit IDT table.
-----Original Message----- From: tiger...@via-alliance.com [mailto:tiger...@via-alliance.com] Sent: Monday, October 27, 2014 2:56 PM To: edk2-devel@lists.sourceforge.net Subject: Re: [edk2] question about setuping IDT in UEFI boot procedure Hi, Jeff: Thanks for your quick reply! Another question: 1. MdeModulePkg\Core\DxeIplPeim\Ia32\DxeLoadFunc.c will reconstruct IDT before handing off to DXE. if (FeaturePcdGet(PcdDxeIplSwitchToLongMode)) { Why it need to reconstruct IDT when trying to switch to Long-mode? } Else { Why does it not need to reconstruct IDT in this case? } Best wishes, ----- Original Message ----- From: Fan, Jeff [mailto:jeff....@intel.com] Sent: 2014年10月27日 14:33 To: edk2-devel@lists.sourceforge.net Subject: Re: [edk2] question about setuping IDT in UEFI boot procedure Exaclty. -----Original Message----- From: tiger...@via-alliance.com [mailto:tiger...@via-alliance.com] Sent: Monday, October 27, 2014 2:17 PM To: edk2-devel@lists.sourceforge.net Subject: Re: [edk2] question about setuping IDT in UEFI boot procedure Hi, Jeff: Thanks for your reply! S3ResumeExecuteBootScript() (in UefiCpuPkg\Universal\Acpi\S3Resume2Pei\S3Resume.c) will call AsmReadIdtr (&PeiS3ResumeState->Idtr) to save IDT. And S3ResumeBootOs()(in UefiCpuPkg\Universal\Acpi\S3Resume2Pei\S3Resume.c) will call AsmWriteIdtr (&PeiS3ResumeState->Idtr) to restore IDT. Why need to save and restore IDT in S3Resume PEIM? Because of BootScriptExecutorDxe driver will call SetIdtEntry() to change IDT? Best wishes, ----- Original Message ----- From: Fan, Jeff [mailto:jeff....@intel.com] Sent: 2014年10月24日 16:48 To: edk2-devel@lists.sourceforge.net Subject: Re: [edk2] question about setuping IDT in UEFI boot procedure On S3 path, S3NvsPageTableAddress () (in UefiCpuPkg/Universal/Acpi/S3Resume.c) will re-create Page Table since we cannot trust the original Page Table saved in ACPINvs memory more. Moreover, we only create page table for < 4G address is due to performance concern. When programming boot script entries, we may access > 4 G MMIO or memory address. Thus, One Page Fault exception handler is required to build Page entry in case > 4G address accessed. Jeff -----Original Message----- From: tiger...@via-alliance.com [mailto:tiger...@via-alliance.com] Sent: Thursday, October 23, 2014 5:55 PM To: edk2-devel@lists.sourceforge.net Subject: Re: [edk2] question about setuping IDT in UEFI boot procedure Hi, Jeff: MdeModulePkg\Universal\Acpi\BootScriptExecutorDxe\X64\SetIdtEntry.c will hook page fault handler. So, is there any story about adding this hook function? I want to understand why adding this code. Thanks a lot! Best wishes, ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel
