JPH0695894A - Information processing system and operating method therefor - Google Patents

Abstract

PURPOSE:To prevent malfunction from being generated in the plural pieces of processes sharing a resource by the generation of prohibition-impossible interruption in an information processing system using the prohibition-impossible interruption. CONSTITUTION:The prohibition-possible interruption can be generated from a processing unit 10 provided with an interruption request line 18 to the processing unit 10 by using an interruption generation mechanism 16. Within a processing started by a prohibition-impossible interruption request line INT0, after the processing outside a dangerous area is performed, then the prohibition- possible interruption is generated by using the interruption generation mechanism 16. Then, operation to the shared resource 14 being the processing of the dangerous area is performed within the interruption processing started by the prohibition-possible interruption. Thus, the processing to be interrupted and the prohibition-impossible interruption processing are prevented from simultaneously entering the dangerous area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interrupt control function of an information processing system and a method of operating the interrupt control function. Technology related to prevention.

[0002]

2. Description of the Related Art Software operating on an information processing system may have a plurality of processes simultaneously. In addition to normal processing, these processes include another process (hereinafter referred to as "interrupt processing") caused by an external factor (hereinafter referred to as "external interrupt").

An external interrupt is an interrupt caused by a signal from a peripheral device such as an input / output device. For example, there is an interrupt from a device that detects a power failure, an external timer, and a floppy disk controller.

The interrupt from the device for detecting the power supply abnormality is as follows. The information processing system may include a peripheral device that monitors the power supplied to the system. When this device detects that an abnormal voltage drop has occurred in the power supply, it is necessary to promptly perform processing in order to prevent system damage. Therefore, in such a case, interrupt is used.

The interrupt from the external timer is as follows. A timer device (external timer) may be provided outside the CPU (central processing unit). The system is designed so that the external timer informs the CPU of the elapse of a preset time or the elapse of a predetermined time.
Even in such a case, the interrupt is used.

The interrupt from the floppy disk controller is as follows. In general, an information processing system is provided with a floppy disk device and a controller for controlling the floppy disk device as an external storage device. The CPU can control the floppy disk device by issuing various commands to the controller. On the other hand, the operating speed itself of such a floppy disk device is much slower than the operation speed of the CPU. Therefore, it is general to operate the CPU so as to start execution of other processing without waiting for the end of the operation of the floppy disk device, thereby improving the operation efficiency of the CPU. In such a case, when the operation of the floppy disk device is completed, it is necessary for the controller to notify the CPU of the end of the operation. An interrupt is used for that purpose.

In addition to the above, there are external factors generated from various peripheral devices. By the way, when a plurality of processes exist simultaneously in the information processing system, the following problems may occur with respect to resources (memory, I / O device, etc.) that may be shared by these processes. . Consider the case where one process is operating on a shared resource. It is conceivable to perform an operation on the resource from an interrupt process triggered by an external interrupt in the middle of the process. If such an operation is performed,
For example, in memory, data integrity may be lost, and the entire process that shares the resource may fail.

[0008] Therefore, it is considered that a process portion that manipulates a resource that may be shared with another process in a certain process is a dangerous portion for maintaining the consistency of the system for the entire system. Hereinafter, such a program part will be referred to as a "dangerous area".

When a process in which such a dangerous area exists is executed, the following method is adopted in order to prevent a failure from occurring in the entire process related to the shared resource. The process in which the hazardous area exists is
Disable external interrupts before starting execution of the hazardous area. Then, after the execution of the dangerous area is completed, the prohibition of the external interrupt is released. As a result, when an interrupt is generated in the dangerous area of a process due to an external factor, acceptance of the external interrupt is delayed until the dangerous area of the currently executing process ends and the interrupt prohibition is released. It After the end of the dangerous area, the shared resource is operated by the processing of the accepted external interrupt.

By doing so, it is possible to prevent a plurality of processes from entering the dangerous area at the same time, and to realize a sequential operation on the shared resource. Then, there is no fear that a failure will occur in the entire process related to this shared resource.

[0011]

However, in general, an information processing system may use an interrupt that cannot be prohibited due to an external factor (hereinafter referred to as "non-prohibited interrupt"). For example, an interrupt from a device for detecting a power failure, an interrupt from a system reset switch, a system abort switch, or the like is such an unprohibited interrupt.

For example, if a power failure occurs, the system may be damaged unless immediate processing is performed. Therefore, the power failure is much more urgent than an interrupt from a peripheral device such as an external storage or a communication device. Therefore, it is common to use such highly urgent ones as non-prohibition interrupts.

Such a non-disabled interrupt is accepted even in the interrupt prohibited state. Therefore, even if a certain process is in the dangerous area period, it is accepted when a non-prohibitable interrupt occurs, and the shared resource is operated by the interrupt processing for the non-prohibitable interrupt. There is a possibility that it will end up. If such an operation is performed, there is a problem that a failure occurs in the entire process related to the shared resource.

The present invention has been made in order to solve the above-mentioned problems, and in an information processing system using a non-prohibited interrupt, resources are shared by the occurrence of a non-prohibited interrupt. An object of the present invention is to provide an information processing system and its operating method capable of preventing a failure from occurring in all of a plurality of processes.

[0015]

An information processing system according to claim 1 has an interrupt processing function for a plurality of interrupt levels including interrupts that cannot be prohibited, and is for executing a program. In order to generate an interrupt request signal of a predetermined prohibitable level and give it to the processing means in response to the processing means and a signal which is connected to the processing means and which gives an instruction to generate an external interrupt. Interrupt generating means.

According to a second aspect of the present invention, there is provided an information processing system operating method, which comprises a processing means for executing a program, having an interrupt processing function for a plurality of interrupt levels including interrupts that cannot be prohibited. An interrupt for connecting to the processing means and generating an interrupt request signal of a predetermined forbidden level in response to a signal instructing the generation of an external interrupt given from the processing means and giving it to the processing means. It is a method of operating an information processing system including a generation unit. This operation method is
When a non-prohibitable interrupt occurs, a step of executing a predetermined first interrupt processing program that does not include a dangerous area by the processing means, and an external step for the interrupt generating means from the first interrupt processing program. In response to the step of outputting a signal instructing the generation of an interrupt and ending the first interrupt processing program, and in response to the signal instructing the generation of an external interrupt output by the first interrupt processing program, At the step of generating an interrupt request level interrupt request signal to the processing means by the interrupt generation means, and at the stage when the interrupt of the disableable level to the processing means becomes available, the interrupt request signal of the disableable level is sent. In response to executing a predetermined second interrupt processing program including the dangerous area.

[0017]

In the information processing system according to the first aspect, in the interrupt processing program executed when an interrupt that cannot be prohibited occurs, only the processing that does not include the dangerous area is executed, and then the interrupt is generated. A signal for instructing the means to generate an external interrupt is generated and the processing is ended. In response to the signal instructing the generation of the external interrupt, an interrupt request signal of an inhibitable level is given to the processing means by the interrupt generating means. The program can be configured to execute the processing of the dangerous area in the interrupt processing by the interrupt request signal of the prohibition level.

In the method of operating the information processing system according to the second aspect of the present invention, when an interrupt that cannot be prohibited occurs, the first interrupt processing program that does not include the dangerous area is first executed.
The first interrupt processing program outputs a signal instructing the interrupt generating means to generate an external interrupt and ends the processing.
In response to the signal instructing the generation of the external interrupt, an interrupt request signal of an inhibitable level is generated by the interrupt generation means and given to the processing means. At the stage where the processing means can accept the interrupt of the prohibition level, the second interrupt processing program including the dangerous area is executed in response to the interrupt request signal generated by the interrupt generation means. . The processing including the dangerous area is not performed in the processing for the interrupt that cannot be prohibited, and is always performed in the interrupt processing of the prohibition level.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, an information processing system according to an embodiment of the present invention is connected to a processing unit 10 having a plurality of interrupt request lines 18 and a processing unit 10 by a data and address bus 22. Stored memory 12. The interrupt request line 18 is a non-disabled interrupt request line INT0.
And prohibition interrupt request lines INT1 to INTn.
The memory 12 includes a shared resource 14 shared by a plurality of processes executed by the processing unit 10.

The information processing system further includes a data and address bus 22 to the processing unit 10 and an interrupt output request line 20 to disable the interrupt request line INT1.
.. to INTn, and an interrupt generation mechanism 16 for generating an interrupt of a predetermined prohibition level to the processing unit 10 in response to a signal instructing the generation of an external interrupt from the processing unit 10. Including and

Referring to FIG. 2, the interrupt generation mechanism 16 sends the data and address bus 22 to the processing unit 10.
The write / read control circuit 30 and the data bus buffer 32 which are connected by the processing unit 1 controlled by the write / read control circuit 30 and via the data bus buffer 32.
An interrupt request register 34 for storing a signal for instructing the generation of an external interrupt given from 0, and prohibition interrupt request lines INT1 to INT connected to the interrupt request register 34
control circuit 36 for generating an interrupt request to any one of n. Actually, a specific address is assigned to the interrupt generating mechanism 16, and an interrupt request is generated in response to the output of the specific address signal from the processing unit 10.

Consider a case where a program executed on the processing unit 10 includes a plurality of processes, and the plurality of processes share the shared resource 14 of the memory 12 to operate. Further, it is assumed that the shared resource 14 may be operated even in the interrupt processing for the external interrupt received by the processing unit 10.

In the information processing system according to this embodiment,
In order to solve the conventional problems, the program structure is as follows. First, in the dangerous area where each process operates the shared resource 14, the following procedure is always followed.

Prohibit other interrupts. The shared resource 14 is operated.

Allow other interrupts. The above-mentioned periods (1) to (4) are an interrupt prohibition section in which the operation to the shared resource 14 by another process or interrupt processing is prohibited.

When a prohibition-disabled interrupt occurs in this interrupt-prohibited section, the processing unit 10 accepts this prohibition-disabled interrupt even though it is an interrupt-prohibited section. The program executed in the interrupt process in this case has the following configuration.

Processing other than the operation of the shared resource, that is, processing of an area other than the dangerous area is performed.

The interrupt generation mechanism 16 is operated to generate a predetermined level of prohibitable interrupt for the processing unit 10.

The interrupt processing is terminated, and the non-prohibited interrupt is restored. By performing the above-mentioned processing, the operation of the above-mentioned shared resource, which has been interrupted by the occurrence of the non-prohibited interrupt, is restarted.

In the above-mentioned prohibition interruption processings 1 to 3,
The shared resource is not operated. Therefore, the above process is temporarily interrupted by a non-inhibitable interrupt,
Even if the processing is restarted after the processing in step 1, the shared resource will not be destroyed due to the occurrence of the non-prohibitable interrupt. That is, no trouble occurs in the entire process related to the shared resource 14.

When it is necessary to operate the shared resource 14 in response to the occurrence of a non-prohibit interrupt, the following processing is performed. By the above-mentioned processing, a prohibitable interrupt is generated. This prohibitable interrupt is not accepted immediately because of the interrupt prohibition process performed in, and is not executed unless the process in is performed. On the other hand, if this process is executed, the prohibitable interrupt generated in is accepted.

In the accepted prohibition interrupt process, the following shared resource operation is performed in the same manner as the above-described processes (1) to (3).

Prohibit other interrupts. The shared resource 14 is operated.

Allow other interrupts. If the processes (1) to (3) are performed in the non-prohibit interrupt process, the processes (1) to (4) are dangerous areas that collide with the processes (1) to (5) performed in the interrupted process. Conventionally, such processing has been performed in the non-inhibitable interrupt processing, so that there is a fear that the shared resource is destroyed. However, according to the present invention, the processes (1) to (3) are not executed in the non-inhibitable interrupt process itself, but are executed in the inhibitable interrupt process generated from the non-inhibitable interrupt process. Therefore, the process of ~ is interrupted ~
There is no fear that the processing of 1) will be executed, and it becomes possible to perform sequential processing for the shared resource. That is,
It is possible to avoid a situation in which both the process of performing the interrupt and the interrupt process accompanying the non-prohibitable interrupt enter the dangerous area.

In order to enable the processing as described above,
The software executed by the processing unit 10 needs to have the following structure.

(A) In processes other than the interrupt process activated by the non-prohibited interrupt, software is created so that the interrupt is prohibited only in the dangerous area as shown by.

(B) The interrupt process activated by the non-inhibitable interrupt is preliminarily divided into the following two or more processes, and the software is created so that they are separate processes.

(I) Process consisting of a processing block that does not operate shared resources (ii) Process consisting of a processing block that operates shared resources Inside this process (ii) is the same as the normal prohibitable interrupt process. It does the processing of.

(C) When the non-prohibitable interrupt occurs, the above process (i) is started.

(D) In the process (i), a process of generating a prohibitable interrupt of a predetermined level is performed immediately before the end thereof.

(E) Then, in response to the prohibitable interrupt generated in the above (d), the above process (ii) is activated.

Sharing is achieved by configuring the information processing system as shown in FIGS. 1 and 2 and configuring each process executed in the processing unit 10 as shown in (a) to (e) above. It is possible to prevent the destruction of resources and prevent the possibility of malfunction in all processes related to shared resources.

FIG. 3 is a software configuration diagram showing a configuration of software processing executed by the information processing system shown in FIGS. Referring to FIG. 3, the interrupted process first performs an interrupt prohibition 40 and then a shared resource operation 42.
When the operation 42 of the shared resource is completed, the interrupt permission 44 is given. From the interrupt prohibition 40 to the interrupt permission 44 is a dangerous area of interrupted processing.

On the other hand, the non-inhibitable interrupt process 46 is accepted even if the interrupted process is in the dangerous area, and performs the following process. First, the non-prohibitable interrupt process 46 performs a process 48 other than the shared resource operation, and then, immediately before the return 52, a prohibition-prohibited interrupt generation 50 is performed. The return 52 terminates this prohibition prohibition interrupt process.

On the other hand, the prohibitable interrupt process 54 executed in response to the occurrence 50 of the prohibitable interrupt is executed only after the interrupt permission 44 of the interrupted process. In the process, an interrupt prohibition 56 is first performed, followed by a shared resource operation 58 and an interrupt permission 60. From the interrupt prohibition 56 to the interrupt permission 60 is a risk area of the prohibitable interrupt processing. After the interrupt permission 60, the prohibition interrupt process 54 is terminated by the return 62.

Since the prohibitable interrupt process 54 is executed only after the interrupt permission 44 of the interrupted process, the prohibitable interrupt process 54 and the interrupted process cannot enter the dangerous area at the same time. Absent. Therefore, there is no risk that the shared resource will be destroyed by the occurrence of the non-prohibitable interrupt process 46, and there will be no risk that a process related to this shared resource will malfunction.

FIG. 4 is a timing chart showing the operation of the information processing system of the above embodiment. First, at the time t0 during execution of the interrupted process, the interrupt is prohibited and enters the danger area of the interrupted process. It is assumed that the impossible prohibition interrupt process occurs at time t1 before the end of the dangerous area. As a result, the non-interrupt processing is interrupted, and the execution of the non-prohibitable interrupt processing is started. Although the non-prohibitable interrupt processing ends at time t3 and the control returns to the interrupted processing, the non-prohibitable interrupt processing generates a prohibitable interrupt at time t2 prior to the return. This interrupt can be prohibited, and due to the interrupt prohibition performed at time t0, it cannot be accepted immediately after the non-disabled interrupt processing ends at time t3.

The execution of the interrupted process is resumed at time t3 and ends at time t4. At time t4, interrupt permission is performed and the dangerous area of the interrupted process ends.

At time t4, an interrupt is permitted by the interrupted process, so that the forbidden interrupt generated at time t2 is accepted. That is, the acceptance of the prohibitable interrupt generated at time t2 is delayed until time t4. In this prohibition interrupt process, after the acceptance, the interrupt prohibition process is performed at time t5 to enter the dangerous area. After the operation on the shared resource is performed, the interrupt permission is performed at time t6, and the disallowable interrupt process is terminated at time t7 to return to the interrupted process. The interrupted process restarts from time t7.

Although the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments. For example, in the above-described embodiment, a non-inhibitable interrupt was generated for processing unit 10 by only one interrupt request line.
However, the present invention can also be applied to an information processing system utilizing a plurality of non-prohibitable interrupts. Further, as the interrupt generation mechanism 16, new hardware may be created, or an existing interrupt controller or the like may be used.

[0051]

As described above, in the information processing system according to claim 1, the interrupt request signal of the prohibition level is generated from the non-prohibition interrupt to the processing means by using the interrupt generation means. You can The shared resource is not manipulated in the prohibition-disabled interrupt process, and the shared resource is manipulated within the interrupt process of the prohibition-prohibited level generated by this prohibition-disabled interrupt. Due to the occurrence of
It is possible to prevent simultaneous execution of dangerous areas of multiple processes. Therefore, it is possible to provide an information processing system capable of preventing a failure from occurring in all of a plurality of processes sharing a resource due to the occurrence of an unprohibitable interrupt.

In the operating method of the information processing system according to the second aspect of the invention, when an interrupt that cannot be prohibited occurs,
The first interrupt processing program that does not include the dangerous area is executed, and the interrupt generation means can be used to generate an interrupt at a prohibition level. By performing the processing of the dangerous area only within the interrupt of the forbidden level, it is possible to prevent a plurality of processes from entering the dangerous area at the same time even when the interrupt that cannot be prohibited occurs. As a result, it is possible to provide an operation method of the information processing system capable of preventing a failure from occurring in all of the plurality of processes sharing the resource due to the occurrence of the non-prohibitable interrupt.

[Brief description of drawings]

FIG. 1 is a block diagram of an information processing system according to an embodiment of the present invention.

FIG. 2 is a detailed block diagram of an interrupt generation mechanism.

FIG. 3 is a software configuration diagram of an embodiment of the present invention.

FIG. 4 is a timing chart explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

 10 Processing Unit 12 Memory 14 Shared Resource 16 Interrupt Generation Mechanism 18 Interrupt Request Line 20 Interrupt Output Request Line 22 Data and Address Bus

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[Procedure amendment]

[Submission date] December 7, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

FIG. 4 is a timing chart showing the operation of the information processing system of the above embodiment. First, at the time t0 during execution of the interrupted process, the interrupt is prohibited and enters the danger area of the interrupted process. It is assumed that the impossible prohibition interrupt process occurs at time t1 before the end of the dangerous area. This
The interrupt processing is interrupted, and starts execution of the prohibited not interrupt processing. Although the non-prohibitable interrupt processing ends at time t3 and the control returns to the interrupted processing, the non-prohibitable interrupt processing generates a prohibitable interrupt at time t2 prior to the return. This interrupt can be prohibited, and due to the interrupt prohibition performed at time t0, it cannot be accepted immediately after the non-disabled interrupt processing ends at time t3.

Claims (2)

[Claims] 1. A processing unit having an interrupt processing function for a plurality of interrupt levels including non-inhibitable interrupts and for executing a program; and a processing unit connected to the processing unit, An information processing system including: an interrupt generating means for generating an interrupt request signal of a predetermined prohibition level and giving it to the processing means in response to a signal instructing the generation of an external interrupt. 2. Processing means for interrupting a plurality of interrupt levels including non-disabled interrupts and for executing a program; and processing means connected to said processing means, An information processing system including an interrupt generation means for generating an interrupt request signal of a predetermined prohibition level and giving it to the processing means in response to a signal instructing the generation of an external interrupt. An operating method, when a non-inhibitable interrupt occurs, a step of executing a predetermined first interrupt processing program that does not include a dangerous area by the processing means; and, from the first interrupt processing program, Outputting a signal instructing the generation of an external interrupt to the interrupt generating means to terminate the first interrupt processing program; and output by the first interrupt processing program. Responsive to a signal instructing the generation of the external interrupt, the interrupt generation means generates an interrupt request signal of the prohibition level to the processing means, and a prohibition level of the processing means. A step of executing a predetermined second interrupt processing program including a dangerous area in response to the interrupt request signal of the prohibition level at the stage when the interrupt can be accepted. How it works.