Method for entering system management mode, processor, and computer system

Patent metadata

Field	Value
Publication number	US-12430163-B2
Application number	US-202418619642-A
Country	US
Kind code	B2
Filing date	Mar 28, 2024
Priority date	Nov 30, 2023
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

The present invention relates to a method for a processor and a computer system to enter system management mode (SMM). The method is applied to the processor, which includes at least one logical core. The method includes entering the SMM in response to a system management interrupt (SMI), storing current state information to a corresponding state save area; setting operation mode to target operating mode, and executing the SMI handler under the target operating mode. The address of the state save area, the address of the core configuration information memory space, and the address of the SMI handler can be determined directly. Each logical core may enter the target operating mode directly through hardware setting every time after entering the SMM, and thus does not need to perform a fixed operation of mode switching when executing the SMI handler, which may improve the execution efficiency of the SMI handler.

First claim

What is claimed is:

1. A method for entering a system management mode, wherein the method is applied to logical cores in a processor, the processor comprises at least one logical core and at least one module specific register (MSR), each of the at least one MSR stores an address related to a system management random access memory (SMRAM) corresponding to the logical core, and the SMRAM includes a core configuration information memory space configured to store core configuration information that corresponds to the logical core, and the method comprises:
entering the system management mode (SMM) in response to a system management interrupt (SMI);
storing current state information into a state save area corresponding to the logical core;
determining an address of the core configuration information memory space that corresponds to the logical core according to the address stored in the at least one MSR;
setting an operating mode to a target operating mode by hardware of the processor before entering the SMM, wherein the target operating mode includes 64 bit mode and 32 bit mode; and
executing an SMI handler under the target operating mode, wherein a mode switch is not performed during executing the SMI handler and the mode switch indicates switching the operating mode.

2. The method as claimed in claim 1 , wherein the method further comprises:
determining the address of the core configuration information memory space that corresponds to the logical core according to the address stored in the at least one MSR, in which the core configuration information includes mode setting information, and the mode setting information indicates a setting value of each of registers corresponding to the target operating mode; and
setting each of the registers corresponding to the target operating mode according to the mode setting information, wherein the registers corresponding to the target operating mode include one or more of the following: CR0 register, CR3 register, CR4 register, EFER register, segment register, and CS register; wherein the segment registers include one or more DS register, ES register, FS register, and GS register.

3. The method as claimed in claim 2 , wherein a PG bit and a PE bit of the CR0 register are set to 1, the CR3 register indicates an address of a page where programs are located in the SMM; wherein the CR4 register indicates basic configuration information of the processor; wherein a LME bit of the EFER register is set to 1; wherein an L bit of the CS register is set to 1, which indicates that the 64 bit mode is enabled.

4. The method as claimed in claim 1 , wherein the core configuration information includes: mode control information, which is configured to indicate the target operating mode that the logical core needs to enter.

5. The method as claimed in claim 1 , wherein the SMRAM includes the state save area,
wherein the method further comprises: determining an address of the state save area that corresponds to the logical core according to the address stored in the at least one MSR.

6. The method as claimed in claim 1 , wherein the method further comprises:
setting each of registers corresponding to an operating environment according to operating environment information, wherein the registers corresponding to the operating environment include general purpose registers, in which the core configuration information includes the operating environment information, and the operating environment information can indicate a setting value of each of the registers of the logical core corresponding to the operating environment in the SMM.

7. The method as claimed in claim 6 , wherein the at least one logical core includes a first logical core and at least one second logical core; wherein the at least one MSR includes a first MSR configured to store a base address of the first logical core, and the first MSR is fabricated outside the logical cores;
wherein in each SMRAM, a memory space corresponding to a preset address offset of the state save area is the state save area of the logical core corresponding to the SMRAM, and a memory space corresponding to a preset address offset of the core configuration information is the core configuration information memory space of the logical core corresponding to the SMRAM; wherein a base address of the SMRAM is an address of the SMI handler;
wherein the method comprises:
using the first logical core to determine the base address obtained from the first MSR as the base address of the SMRAM corresponding to the first logical core; and/or
determining, using the second logical core, the base address of the SMRAM corresponding to the second logical core according to the association between the base address obtained from the first MSR and the base address corresponding to the second logical core.

8. The method as claimed in claim 6 , wherein the at least one MSR includes a second MSR for each of the logical cores, and each second MSR is configured to store a base address of the SMRAM of the logical core corresponding to the second MSR;
wherein in each SMRAM, a memory space corresponding to a preset address offset of the state save area is the state save area of the logical core corresponding to the SMRAM, and a memory space corresponding to a preset address offset of the core configuration information is the core configuration information memory space of the logical core corresponding to the SMRAM; wherein a base address of the SMRAM is an address of the SMI handler;
wherein the method further comprises: determining, using each of the logical cores, the base address obtained from the second MSR as the base address of the SMRAM corresponding to the logical core.

9. The method as claimed in claim 6 , wherein the core configuration information includes an address of the SMI handler.

10. The method as claimed in claim 9 , wherein the at least one MSR includes a third MSR and a fourth MSR for each of the logical cores, each third MSR is configured to store an address of the state save area of the logical core corresponding to the third MSR, and each fourth MSR is configured to store the address of the core configuration information memory space of the logical core corresponding to the fourth MSR.

11. The method as claimed in claim 9 , wherein the core configuration information memory space stores a configuration information structure generated by the core configuration information of the logical core corresponding to the core configuration information memory space, the configuration information structure includes a plurality of information fields, and each of the information fields is configured to store the core configuration information or a memory address of the core configuration information.

12. The method as claimed in claim 9 , wherein the at least one MSR includes a second MSR for each of the logical cores, and each second MSR is configured to store the address of the core configuration information memory space and an address of the state save area of the logical core corresponding to the second MSR.

13. The method as claimed in claim 6 , wherein the SMRAM further comprises:
a handler memory space configured to store the SMI handler.

14. The method as claimed in claim 13 , wherein the at least one MSR includes a third MSR, a fourth MSR, and a fifth MSR for each of the logical cores, each third MSR is configured to store an address of the state save area of the logical core corresponding to the third MSR, each fourth MSR is configured to store the address of the core configuration information memory space of the logical core corresponding to the fourth MSR, and each fifth MSR is configured

Assignees

• Shanghai Zhaoxin Semiconductor Co Ltd

Inventors

• Wang Weilin
• Niu Yankui
• Liu Jinglong
• Wang Jiangbo
• Guan Yingbing
• Cheng Long

Classifications

• G06F9/4812 Primary

  by interrupt, e.g. masked · CPC title

• Y02D10/00

  Energy efficient computing, e.g. low power processors, power management or thermal management · CPC title

• G06F15/80

  comprising an array of processing units with common control, e.g. single instruction multiple data processors (G06F15/82 takes precedence {; for correlation function computation G06F17/15}) · CPC title

• G06F9/48 Primary

  Program initiating; Program switching, e.g. by interrupt · CPC title