TWI427536B - System and apparatus for deleting and writing data of dmi in the linux operation system - Google Patents

Description

Method and device for erasing DMI data under Linux system

The invention relates to a method and a device for erasing data, in particular to a method and a device for erasing DMI data.

DMI (Desktop Management Interface) is a management system that helps collect information about computer systems. It is used to store information about the computer system itself and its surrounding areas. This information includes the serial number of the motherboard and the manufacturer (Manufacture). The hardware event information (Event Log) of the computer system each time it boots, starts, and shuts down.

DMI usually saves the above data in a 4KB data area in the BIOS (Basic Input Output System). This data area is usually called MIFD (Management Information Format Database). .

There are two ways to access data in the DMI MIFD. The first method is a Table-based Method, and the second is through a Plug-and-Play function interface. Among them, the first method only provides the function of viewing MIFD data, and can not erase the data in MIFD. The second way is to erase the MIFD data by calling the PnP (Plug-and-Play) call to the Calling Convention. However, the PnP call routine It is only available in Real-mode and 16-bit protected mode systems. The DOS system is a 16-bit real mode that can directly call the PnP call routine. The DMI MIFD data is erased under the DOS system through the second method.

However, the Linux system is a 32-bit protected mode, which cannot directly call the PnP call routine. As mentioned above, the serial number of the motherboard, the manufacturer of the motherboard, and the event log of the hardware system each time the computer system boots, starts, and shuts down are the data in the DMI MIFD. In the following, the method of erasing the DMI MIFD data under the Linux system is illustrated by taking the serial number of the main board Event Log and the programming main board as an example.

The main board Event Log records the hardware fault information every time the system boots, starts, and shuts down. By viewing this record, you can know the cause and time of the abnormal situation, and provide a basis for solving the abnormal problem. However, the Event Log has a limited storage area. When the storage area is full, the system will report an error message when booting, starting, etc., and request to clear the previous Event Log. In addition, the manufacturer will also clear the Event Log before the motherboard is shipped. The traditional methods for clearing Event Log are as follows: First, enter the BIOS page to execute the Configuration/Setup Utility tool provided by the BIOS manufacturer to clear the Event Log; second, install the DOS system, and directly call the PnP call routine to clear the Event Log under the DOS system.

The manufacturer must write the serial number of the motherboard during the process of making the motherboard. At present, the method of programming the serial number of the motherboard is also to install the DOS system, and directly call the PnP calling routine to perform the programming operation under the DOS system.

The above clearing or programming of the DMI MIFD data either needs to enter the BIOS interface, or requires additional installation of the DOS system, which is undoubtedly very troublesome. In addition, due to The DOS system is a single-threaded operating system. Therefore, in the DOS system, the programming operation is performed. If the data to be written is incorrect, the burning phenomenon often occurs after the burning operation is performed.

In view of the above, it is necessary to propose a method and device for implementing DMI data in a Linux system, which can call the PnP calling routine in the Linux operating system to implement data erasing in the DMI MIFD.

A method for erasing DMI data under Linux system. The method includes: creating a new process; mapping a BIOS interrupt vector table and BIOS data to a space at the bottom of the process; selecting a subspace smaller than the space in the space as a system stack space of the virtual 8086 mode, and The address of the stack space of the system is assigned to the context of the process; a PnP tag is searched through the string alignment method from the physical address of the BIOS to find a PnP call in a data structure next to the PnP tag. Entry point; set the permission permission for IO operations so that the PnP call routine can perform input/output operations; receive 16-bit parameters, convert the 16-bit parameters to 32-bit, and store the parameters to The above system stacking space; setting the operating environment of the virtual 8086, and assigning the running environment to the context of the process; setting the signal blocking to prevent other processes from interrupting the process to jump to the virtual 8086 mode; and utilizing Linux The virtual 8086 system call function provided by the system kernel causes the process to enter the virtual 8086 mode and executes the PnP call routine to populate the above system. The parameter is read out in the stack space, and the DMI data is erased according to the parameter.

A device for erasing DMI data under a Linux system. The device includes: a process creation module for creating a new process; a virtual 8086 memory environment construction module, The interrupt vector table and the BIOS data for mapping the BIOS to a space at the bottom of the process; the stack space building module is configured to select a subspace smaller than the space in the space as the system stack space of the virtual 8086 mode, and The address of the stacking space of the system is assigned to the context of the process; the entry point finding module is configured to search for a PnP label from the physical address of the BIOS through a string alignment method, so as to be next to the PnP label. The entry point of the PnP calling routine is found in a data structure; the permission setting module is used to set the permission permission of the IO operation, so that the PnP calling routine can perform input/output operations; the parameter storage module is configured to receive 16-bit parameter, the 16-bit parameter is converted into 32-bit, and the parameter is stored in the above-mentioned system stacking space; the operating environment setting module is used to set the operating environment of the virtual 8086, and the operating environment is assigned The context of the process; the signal blocking setting module is used to set the signal blocking to prevent other processes from interrupting the process to jump to the virtual 8086 mode; and The calling module is used to make the process enter the virtual 8086 mode by using the virtual 8086 system calling function provided by the Linux system kernel, and execute the PnP calling routine to read the parameter from the above system stacking space, and according to the parameter Write and erase DMI data.

Compared with the prior art, the method and device for implementing the DMI data in the Linux system can be called by the PnP calling routine in the Linux operating system to implement data erasing in the DMI MIFD, saving time and operation. And even if the data is programmed incorrectly, there will be no crash.

1‧‧‧ computer

100‧‧‧Process Creation Module

101‧‧‧Virtual 8086 Memory Environment Construction Module

102‧‧‧Stacking space building module

103‧‧‧Entry Point Search Module

104‧‧‧Permission Setting Module

105‧‧‧Parameter storage module

106‧‧‧Running environment setting module

107‧‧‧Signal blocking setting module

108‧‧‧ function call module

109‧‧‧Judgement module

110‧‧‧ prompt module

20‧‧‧BIOS

200‧‧‧MIFD

FIG. 1 is a structural diagram of a preferred embodiment of an apparatus for erasing DMI data in a Linux system according to the present invention.

2 is a schematic diagram of a preferred embodiment of a method for erasing DMI data in a Linux system according to the present invention Implement the flow chart.

Referring to FIG. 1, a block diagram of a preferred embodiment of an apparatus for erasing DMI data in a Linux system is provided. The device may be a computer 1, or a mobile phone, a server, a PDA (Personal Digital Assistant), or the like. In this embodiment, the device takes the computer 1 as an example. The computer 1 is equipped with a Linux operating system. As we all know, Linux is a multiplexed operating system, users can run multiple applications at the same time, create multiple processes. The computer 1 also includes a BIOS (Basic Input Output System) 20. The BIOS 20 includes a MIFD 200 (Management Information Format Database).

The computer 1 includes a plurality of functional modules. The function module is a program segment for completing a specific function, and is more suitable for describing the execution process of the software in the computer than the software program itself. Therefore, the description of the software program in the present invention is described by a module.

The plurality of function modules mainly include: a process creation module 100, a virtual 8086 memory environment structure module 101, a stack space construction module 102, an entry point search module 103, a permission setting module 104, and a parameter storage module. The group 105, the operating environment setting module 106, the signal blocking setting module 107, the function calling module 108, the determining module 109, and the prompting module 110.

The process creation module 100 is used to create a new process. When the process creation module 100 discovers an event requesting the creation of a new process by detecting the user's behavior, the process creation primitive is invoked, and a new process is created as follows: (1) Applying for a blank process control block (Process Control) Block, referred to as PCB); (2) allocate resources for new processes, allocate necessary programs and data for new processes, and user stacks Memory space; (3) initialize the process control block; (4) insert the new process into the ready queue.

The virtual 8086 memory environment construction module 101 is configured to map the interrupt vector table of the BIOS 20 and the data of the BIOS 20 to a space at the bottom of the process, such as 1 MB, to construct a memory environment suitable for the virtual 8086 mode operation.

The stack space building module 102 is configured to select a sub-space of less than 1 MB, for example, 7 KB, in a 1 MB space at the bottom of the process, as a system stack space of the virtual 8086 mode. The system stacking space is a space for temporarily storing the interrupt point address and protecting (restoring) the field data when the function is called. Further, the stack space building module 102 assigns the address of the system stack space to the context of the process (hereinafter referred to as a process context). The process context represents various information about the process, including various variables, registers, and the operating environment of the process. When the process is switched, the next time you switch back to continue execution, you can use the process context to know the state of the process.

The entry point finding module 103 is configured to search for a PnP label "$PnP" from the physical address f0000~fffff of the BIOS 20 by means of string alignment. Next to the PnP tag, a data structure is stored, and the data structure indicates a segment address and an offset address of the 16-bit real mode of the PnP calling routine, so the entry point finding module 103 can The entry point of the PnP calling routine is found in the data structure.

The permission setting module 104 is configured to set an allow permission of the IO operation, so that the PnP calling routine can perform an input/output operation.

The parameter storage module 105 is configured to receive a 16-bit parameter, and the 16-bit parameter Convert to a 32-bit parameter and store the parameter in the system stack space above. The parameters include a PnP sub-function number, a data type and a data content to be written into the MIFD 200.

The running environment setting module 106 is configured to set an operating environment of the virtual 8086. The operating environment of the virtual 8086 includes a system level context, a process control block of a register context, a program control block, various control registers, and the like. Further, the runtime environment setting module 106 assigns the runtime environment to the process context.

The signal blocking setting module 107 is configured to set a signal blocking to prevent other processes' signals from interrupting the process to jump to the virtual 8086 mode.

The function calling module 108 is configured to make the process enter the virtual 8086 mode by using the virtual 8086 system calling function provided by the kernel of the Linux system, and execute the PnP calling routine. After executing the PnP calling routine, the PnP calling routine can read the above parameters from the above-mentioned system stacking space, and perform corresponding erasing operations on the data in the MIFD 200 according to the read parameters.

The determining module 109 is configured to determine whether the value in the AX register in the CPU is 0. If the PnP call routine is successfully executed, the value in the AX register is zero. Otherwise, if the PnP call routine is not successfully executed, an error code will be returned in the AX register.

The prompting module 110 is configured to return the above error code when determining that the value in the AX register is not 0, to prompt the user that the PnP calling routine is not successfully executed.

Referring to FIG. 2, it is a flowchart of an implementation of a preferred embodiment of a method for erasing DMI data in a Linux system of the present invention.

In step S10, the process creation module 100 discovers that a new request is created by detecting the behavior of the user. After the event of the process, the calling process creates the primitive, and creates a new process by the following steps: (1) applying for a blank Process Control Block (PCB); (2) allocating resources for the new process, for the new process. The program and data and the user stack allocate the necessary memory space. (3) Initialize the process control block (4) Insert the new process into the ready queue.

In step S11, the virtual 8086 memory environment structure module 101 maps the interrupt vector table of the BIOS 20 and the data of the BIOS 20 to a space at the bottom of the process, for example, 1 MB, to construct a memory environment suitable for the virtual 8086 mode operation.

In step S12, the stack space building module 102 selects a subspace smaller than 1 MB in the 1 MB space at the bottom of the process, for example, 7 KB, as a system stack space of the virtual 8086 mode, and assigns the address of the system stack space to the process. Context (hereinafter referred to as the process context).

In step S13, the entry point finding module 103 searches for a PnP tag "$PnP" from the physical address f0000~fffff of the BIOS through a string alignment method.

Step S14, the entry point finding module 103 finds the segment address and the offset address of the 16-bit real mode of the PnP calling routine in a data structure stored next to the PnP tag, thereby finding the entry of the PnP calling routine. point.

In step S15, the permission setting module 104 sets the permission permission of the IO operation so that the PnP calling routine can perform an input/output operation.

In step S16, the parameter storage module 105 receives the 16-bit parameter and converts the 16-bit parameter into a 32-bit parameter. The parameters refer to the PnP sub-function number, the type of data to be written into the MIFD 200, the data content, and the like.

Step S17, the parameter storage module 105 stores the parameter to the above system stack. between.

In step S18, the running environment setting module 106 sets the running environment of the virtual 8086, and assigns the running environment to the process context. The operating environment of the virtual 8086 includes a system level context, a process control block of a register context, a program control block, various types of control registers, and the like.

In step S19, the signal blocking setting module 107 sets the signal blocking to prevent other processes' signals from interrupting the process to jump to the virtual 8086 mode.

In step S20, the function calling module 108 uses the virtual 8086 system calling function provided by the kernel of the Linux system to make the process enter the virtual 8086 mode and execute the PnP calling routine. After executing the PnP calling routine, the PnP calling routine can read the above parameters from the above-mentioned system stacking space, and perform corresponding erasing operations on the data in the MIFD 200 according to the parameters.

In step S21, the determination module 109 determines whether the value in the AX register is 0. If the PnP call routine is successfully executed, the value in the AX register is 0. Otherwise, if the PnP call routine is not successfully executed, an error code will be returned in the AX register.

If the determination module 109 determines that the value in the AX register is 0, the flow is terminated.

Otherwise, if the determining module 109 determines that the value in the AX register is not 0, the prompting module 110 returns the above error code to prompt the user that the PnP calling routine has not been successfully executed, and ends the flow.

The method and device for erasing DMI data in the Linux system provided by the present invention firstly construct a memory environment running in the virtual 8086 mode, and then jump the CPU and the memory operating environment into the virtual 8086 mode, and execute the PnP calling routine. After the execution, return to the Linux system, this process does not need to install the DOS system, thus saving time And operation. In addition, because the Linux system is a multiplexed operating system, the process scheduling mechanism is complete and the system is more stable. In the Linux system, the system can still successfully return to the Linux system even if the data being programmed is incorrect or the PnP calling routine is not successfully executed for other reasons. The system does not crash, so this method is more secure.

The above is only the preferred embodiment of the present invention, and has been used in a wide range of ways. Any other equivalent changes or modifications which are not departing from the spirit of the present invention should be included in the following claims. Inside.

1‧‧‧ computer

100‧‧‧Process Creation Module

101‧‧‧Virtual 8086 Memory Environment Construction Module

102‧‧‧Stacking space building module

103‧‧‧Entry Point Search Module

104‧‧‧Permission Setting Module

105‧‧‧Parameter storage module

106‧‧‧Running environment setting module

107‧‧‧Signal blocking setting module

108‧‧‧ function call module

109‧‧‧Judgement module

110‧‧‧ prompt module

20‧‧‧BIOS

200‧‧‧MIFD

Claims (10)

A method for erasing DMI data in a Linux system, comprising: creating a new process; mapping a BIOS interrupt vector table and BIOS data to a space at the bottom of the process; selecting a subspace smaller than the space in the space as Virtual 8086 mode system stacking space, and assign the address of the system stacking space to the context of the process; look for a PnP tag from the physical address of the BIOS through a string comparison method to be next to the PnP The entry point of the PnP calling routine is found in a data structure of the tag; the permission permission of the I/O operation is set so that the PnP calling routine can perform an input/output operation; the 16-bit parameter is received, and the 16-bit parameter is received. Convert to 32-bit and store the parameter in the above system stack space; set the virtual 8086 running environment, and assign the running environment to the context of the process; set the signal blocking to prevent other processes from interrupting the signal. The process jumps to the virtual 8086 mode; and uses the virtual 8086 system call function provided by the Linux system kernel to make the process enter the virtual 8086 mode. And executing the PnP calling routine to read out the parameter from the above-mentioned system stacking space, and perform erasing operation on the DMI data according to the parameter. The method for erasing DMI data in a Linux system, as described in claim 1, further includes: determining whether a value in the AX register in the CPU is 0; and returning when determining that the value in the AX register is not 0, An error code to prompt the user that the PnP call routine did not execute successfully. A method for erasing DMI data under a Linux system as described in claim 1 of the patent scope, The space is 1 MB and the subspace of the space is 7 KB. The method for erasing DMI data in a Linux system, as described in claim 1, wherein the entry point of the PnP calling routine includes a 16-bit real mode segment address and an offset address. The method for erasing DMI data in a Linux system, as described in claim 1, wherein the parameter includes a PnP sub-function number, a data type to be written, and a data content. The method for implementing DMI data in a Linux system, as described in claim 1, wherein the operating environment of the virtual 8086 includes a system level context, a process control block of a register context, a program control block, and various control registers. . A device for erasing DMI data in a Linux system, comprising: a process creation module for creating a new process; a virtual 8086 memory environment construction module for mapping a BIOS interrupt vector table and BIOS data to the bottom of the process a space; a stacking space building module for selecting a subspace smaller than the space in the space as a system stacking space of the virtual 8086 mode, and assigning the address of the system stacking space to the context of the process; Point finding module for finding a PnP tag from a physical address of the BIOS through a string comparison method to find an entry point of the PnP calling routine in a data structure next to the PnP tag; permission Setting a module for setting permission permissions for I/O operations so that the PnP calling routine can perform input/output operations; a parameter storage module for receiving 16-bit parameters, converting the 16-bit parameters to 32-bit, and store the parameter in the above system stacking space; the operating environment setting module is used to set the operating environment of the virtual 8086, and assign the running environment to the process Context; signal blocking signal setting module for setting the signal blocking to prevent other processes that break The operation of the process jumps to the virtual 8086 mode; and the function call module is used to make the process enter the virtual 8086 mode by using the virtual 8086 system call function provided by the Linux system kernel, and execute the PnP call routine to be from the above system stack space. The parameter is read out, and the DMI data is erased according to the parameter. The device for erasing DMI data under the Linux system, as described in claim 7, wherein the device is a computer, a mobile phone, a server or a PDA. The device for erasing DMI data in a Linux system, as described in claim 7, the device further comprising: a determining module, configured to determine whether a value in the AX register in the CPU is 0; and a prompting module, It is used to return an error code when it is judged that the value in the AX register is not 0, to prompt the user that the PnP calling routine has not been executed successfully. The device for erasing DMI data in a Linux system, as described in claim 7, wherein the parameter includes a PnP sub-function number, a data type to be written, and a data content.