CN107729085A - A kind of On-board software dynamic loading method for supporting address to redirect - Google Patents

Abstract

The invention provides a dynamic loading method of on-board software supporting address redirection, which can realize a simple, highly reliable and redundant address redirection loading method of on-board software. Step 1. Write the embedded software link configuration file; Step 2. Memory detection when the program starts; Step 3. The global attributes of the on-board software are componentized: all global attributes that will change, including those with initial values and those that do not Attributes with initial values are encapsulated into attributes of a component, which is called a program component; step 4, program component instantiation: by obtaining the initial address saved in the global register, map the program component defined in step 3 to Realize the instantiation of program components on the starting address of healthy memory; Step 5, compile and link the entire program to form a burnable binary program file; Step 6, finally burn the binary file to the target device, power on and start normally .

Description

A Dynamic Loading Method of Spaceborne Software Supporting Address Redirection

technical field

The invention relates to a method for dynamically loading spaceborne software supporting address redirection, and belongs to the technical field of spacecraft embedded software implementation.

Background technique

For many embedded on-board computer devices in spacecraft, the internal memory (SRAM) is the direct carrier of software operation, and most of the internal memory is non-repairable and non-replaceable. At present, the processors used by many on-board computer equipment do not have a memory management unit (MMU). After the program is compiled and linked, the memory addresses used for variable access are all physical addresses. Therefore, when an address in the device memory is physically damaged, the (The fault still cannot be recovered after power on again), when the software accesses this address, errors will occur. After a memory failure is discovered, the ground generally adopts a processing measure of switching backup equipment, that is, the current master computer cannot be used normally in the future. The failure of a single computer due to a regional failure of RAM is undoubtedly a great loss for the entire spacecraft.

In the prior art, the patent with the publication number CN106873990A discloses a multi-partition boot method in the embedded system RAM damage mode. Lightweight launcher. The two parts of the program run in different memory address spaces. When the RAM failure causes the normal startup program to fail, start the lightweight startup program to run. The patent with the publication number of CN104461657A discloses a switching and starting device for an embedded system, which includes a processor, a switching signal generating module, a main backup solidified memory, and the like. The device is used to read the boot program from the solidified memory when the solidified memory is powered on, and read the boot program from the backup memory when the solidified memory is powered off. There is also a patent with the publication number CN10288049A disclosing an embedded multi-system self-starting method, which is characterized in that it includes a self-starting circuit and a timer designed separately. After the system is powered on, the timer starts to work, and the self-starting circuit outputs The chip select selects the first memory, the processor loads the boot program from the first memory, the system is initialized, and the timer is turned off if the startup is successful. If the self-starting circuit does not receive the correct status signal before the timer expires, the self-starting circuit outputs a chip select to select the second memory, the processor loads the boot program from the second memory, and the system is initialized.

The above method mainly has the following problems:

(1) Corresponding hardware circuits need to be designed to cooperate with the operation of fault elimination, and in some embedded systems, issues such as cost, power consumption, and volume need to be considered.

(2) The memory address space where the failure occurs is random. In the above method, if the main backup program runs in the same address space, the backup program cannot run after the failure. If the address spaces of the master and backup programs are different, if the fault space overlaps with the address space of the master and backup programs, neither the master nor the backup programs will be able to run.

Therefore, this paper proposes a dynamic loading method of on-board software that supports address redirection. This method combines the software component technology to encapsulate the global attributes of the entire on-board program into a dedicated component. Through the process of component instantiation, the original on-board software The physical address used after compiling and linking is transformed into a logical address, thereby realizing dynamic mapping. After the memory health check is completed when the on-board software is loaded and running, the faulty memory address can be skipped without any impact.

Contents of the invention

The invention provides a dynamic loading method of on-board software that supports address redirection, which can realize a simple, highly reliable and redundant on-board software address redirection loading method, uses software component technology, and uses embedded software to compile and link rules , to solve the problem that the program cannot be loaded and run normally after a certain address or area of memory is physically damaged.

A method for dynamically loading spaceborne software supporting address redirection, comprising the following steps:

Step 1. Write the onboard software link configuration file: define the text section and data section of the onboard software program to be placed in ROM, and the bss section to be placed in RAM, and define the address and size of the memory space where the onboard software program runs;

Step 2, memory detection: when the program starts, it starts to detect from the starting address of the memory space, finds a continuous and correct memory address space that is sufficient for the program, and saves the starting address of the memory address space in the global register ;

Step 3, program component instantiation: first, all the global attributes in the on-board software that will change are encapsulated into the attributes of a component, which is called a program component; address, mapping the program component to the start address to realize the instantiation of the program component;

Step 4, compiling and linking the instantiated program components to form burnable binary program files;

Step 5. Finally, burn the binary program file to the target device, power on and start normally.

Beneficial effects of the present invention:

The present invention combines the software component technology to encapsulate the global attributes of the entire on-board program into a dedicated component. Through the process of component instantiation, the physical address used after compiling and linking the original on-board software is transformed into a logical address, thereby realizing dynamic mapping. The faulty memory address can be skipped after the memory health check is completed when the software is loaded and running without any impact.

Description of drawings

FIG. 1 is a schematic diagram of the present invention using an address redirection method to generate an executable program.

Fig. 2 is a flow chart of the memory detection mechanism at startup of the present invention.

Fig. 3 is a structural diagram of components in the present invention.

FIG. 4 is a layout diagram of memory address space after memory address dynamic mapping in the present invention.

detailed description

As shown in FIG. 1 , the present invention provides a method for dynamically loading on-board software that supports address redirection. The following describes the present invention in detail with reference to the accompanying drawings and examples.

The steps of the on-board software dynamic loading method supporting address redirection of the present invention are as follows:

Step 1: Taking the development of an on-board software as an example, the program code text section is 28K Bytes, the data section is 16KBytes, the bss section is 36K Bytes, and the stack section is 32K Bytes. After comprehensive statistics, it is estimated that the memory usage space will not exceed 128K Bytes. Suppose its RAM starting address is 0x40000000, its size is 1M Bytes, and its damaged memory address is 0x400000FC

Step 2: Use assembly language to write a memory detection program. When the entire program starts, the detection program completes the initialization of the CPU. The detection process starts from the starting address of the memory and searches for a continuous address space sufficient for the program. If the program needs to use 128K byte space, write 0x55555555 and 0xAAAAAAAA feature codes into the subsequent 128K byte space from the starting address and read them for judgment. And save the starting address of the correct space detected this time in the global register. If there is an error in an address in this space, skip the wrong address, start from the address of the next 32 bytes, continue to detect the address space of 128K bytes, and so on, until a continuous correct 128K bytes is found Space, when the sum of the detection start address and detection length exceeds the maximum address of RAM, the program needs to enter an endless loop and wait for the dog bite cutter.

The detection process is shown in Figure 2. After the program starts, it starts to detect the 128K RAM space from the address 0x40000000. An error is found when the address 0x400000FC is detected. At this time, the program re-initializes the detection address and length, and starts from the address 0x40000100. The RAM space of 128K length is detected, and the address 0x40000100 is saved to the global register of the processor after the detection is successful.

Step 3: Componentization of the global attributes of the on-board software:

(a) Encapsulation attributes: all global attributes in the original program design (attributes that will change, including attributes with and without initial values), such as global variables, global arrays, global pointers, global components, etc. An attribute encapsulated into a component, such as defined as struct AppComponent, which contains n attributes, 32-bit integer attribute a, single-precision floating-point attribute b, double-precision floating-point attribute c, unsigned integer pointer attribute d and unsigned Integer array attribute e (128 elements), etc. Among them, a, b, c, and d have initial value requirements, and perform initial assignment operations on them in the initialization interface implemented in (b).

(b) Write the initialization interface: the interface form is generally void AppComponentInit(void). The interface assigns values to the a, b, c, and d attributes of the AppComponent component. This interface needs to be called before the program main body runs to realize the initialization function of the program component.

(c) Publishing interface: Write the publishing interface, and return the pointer to the AppComponent instance through the publishing interface, through which the previously defined global attributes a, b, c, d, and e can be accessed.

The defined program component is mapped to the healthy memory start address 0x40000100 to realize the instantiation of the program component.

Step 4: Finally, compile and link the completed project to form an executable program;

Step 5: After programming to the target device, power on and run.

Claims (4)

1. A method for dynamically loading spaceborne software that supports address redirection, is characterized in that, comprising the following steps: Step 1. Write the onboard software link configuration file: define the text section and data section of the onboard software program to be placed in ROM, and the bss section to be placed in RAM, and define the address and size of the memory space where the onboard software program runs; Step 2, memory detection: when the program starts, it starts to detect from the starting address of the memory space, finds a continuous and correct memory address space that is sufficient for the program, and saves the starting address of the memory address space in the global register ; Step 3, program component instantiation: first, all the global attributes in the on-board software that will change are encapsulated into the attributes of a component, which is called a program component; address, mapping the program component to the start address to realize the instantiation of the program component; Step 4, compiling and linking the instantiated program components to form burnable binary program files; Step 5. Finally, burn the binary program file to the target device, power on and start normally. 2. A kind of on-board software dynamic loading method that supports address redirection as claimed in claim 1, is characterized in that, the on-board software link configuration file that step 1 writes is divided into three sections: program section, band initial value Data segment and data segment with no initial value assigned. 3. A method for dynamically loading on-board software supporting address redirection as claimed in claim 1 or 2, wherein the memory detection program in step 2 is written in assembly language. 4. A kind of on-board software dynamic loading method that supports address redirection as claimed in claim 1 or 2, is characterized in that, described program component comprises component property, initialization interface, publishing interface; Wherein: Component attributes: including global variables, global arrays, global pointers, and global components; Initialization interface: assign values to the attributes with initial value requirements in the program component, that is, initialize; Publishing interface: provide an interface for accessing attributes in this program component.