JPS6373336A - Calling system for privileged program - Google Patents

Abstract

PURPOSE:To make the correction of an operating system unnecessary when a support program is enhanced by providing a prescribed privileged subprogram and non-privileged subprogram respectively in the support program. CONSTITUTION:The support program 3 is started up with a non-privileged level to support the development or the maintenance, etc., of the operating system 2. In the program 3, the non-privileged subprogram 3A including a privileged subprogram call instruction 3A-1 to call the privileged subprogram 3B, is built in. Also, in the program 3, the privileged subprogram 3B including a non-privileged subprogram return instruction 3B-1 to return to the non- privileged subprogram 3A, is built in. In this way, it is possible to make the correction of the operating system unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a privileged program calling system, and particularly to a privileged program calling system for a support program compatible with an operating system when data processing is performed by an electronic computer.

[Conventional technology]

Conventionally, in this type of privileged program calling method, in order to execute support programs such as performance measurement programs and debugging programs corresponding to the operating system, normal calls provided by the operating system such as supervisor calls and gate calls are used. The same method was used to call the service program. For this reason, some of the functions required by the support program have often been built into the operating system as privileged programs.

For example, a service program that acquires information on a specific control block used by the operating system for a debugging program may be pre-built into the operating system as a privileged program.

[Problem that the invention seeks to solve]

In the conventional privileged program calling method described above, some functions of the support program are built into the operating system, so there is a drawback that the operating system also needs to be modified when the support program is enhanced.

For example, in the case of a service program that acquires information about a specific control block, if the scope of the target control block needs to be changed due to a request from the support program, the privileged program built into the operating system must be modified. The need arises.

In view of the above-mentioned points, an object of the present invention is to enable the support program started at a non-privileged level to be executed at the privileged level built into the support program without incorporating some functions of the support program into the operating system. The object of the present invention is to provide a method for calling a privileged program that allows calling a privileged subprogram that is to be used.

[Means for solving problems]

The privileged program calling method of the present invention is a data processing system using a central processing unit that has a privileged level and a non-privileged level as a program execution environment. A support program to be started, a non-privileged subprogram built in this support program and containing a privileged subprogram call instruction for calling a privileged subprogram, and a non-privileged subprogram built in the support program and containing a privileged subprogram call instruction for returning to the non-privileged subprogram. and the privileged subprogram including a subprogram return instruction.

[Effect]

In the privileged program calling method of the present invention, the support program is started at a non-privileged level to support the development and maintenance of the operating system, and the non-privileged subprogram built in the support program has the privilege to call the privileged subprogram. It includes a subprogram call instruction and a non-privileged subprogram return instruction for returning a privileged subprogram built in the support program to a non-privileged subprogram.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The main parts of the data processing system to which the privileged program calling method of this embodiment is applied include a central processing unit 1, an operating system 2, and a support program 3.

The central processing unit 1 has a privileged level and a non-privileged level as a program execution environment, and includes a keyword register IA in which a keyword 2B is set by a keyword setting instruction 2A-1, which will be described later.

Operating system 2 uses keyword register I
Keyword setting command 2A to set keyword 2B to A
-1 and the keyword 2 specified by the keyword setting command 2A-1.
It is composed of B.

The support program 3 is a service program that obtains information on a specific control block used by the operating system 2, for example, and acquires information on a specific control block in the operating system 2 from the terminal by calling the privileged subprogram 3B. A non-privileged subprogram 3A that is displayed on the screen; a privileged subprogram 3B that is called by the non-privileged subprogram 3A and stores information on a specific control block in a control block information storage area 3E;
A keyword register IA in the central processing unit 1 specified by a privileged subprogram call instruction 3A-1 to be described later.
, a stack 3D used by the privileged subprogram call instruction 3A-1, and a control block information storage area 3E that stores information on a specific control block.

The non-privileged subprogram 3A is activated at a non-privileged level, and the privileged subprogram call instruction 3A uses the first operand to specify the keyword 3C and the next operand to specify the privileged subprogram 3B to be called.
-1 is included.

Note that such a privileged subprogram call instruction 3A-
1 is easy to provide.

The privileged subprogram 3B is activated at a privileged level and executes a non-privileged subprogram return instruction 3B-1 that returns control to the return address of the non-privileged subprogram 3A stored in the stack 3D by the privileged subprogram call instruction 3A-1. Contains. Note that it is easy to provide such a non-privileged subprogram return instruction 3B-1.

The stack 3D has a privileged subprogram call instruction 3A.
−1 stored by unprivileged subprogram return instruction 3
Contains a non-privileged subprogram return address storage area 3D-1 referenced by B-1.

Referring to FIG. 2, the processing in the non-samurai privilege subprogram 3A includes a privileged subprogram calling step 21;
and a control block information display step 22.

Referring to FIG. 3, the processing in the privileged subprogram 3B consists of a control block information storage step 31.

Next, the operation of the privileged program calling system of this embodiment configured as described above will be explained.

When the system is started, the operating system 2 executes two keyword setting subprograms before the non-privileged program 3A can be executed.

For example, the keyword setting subprogram 2A stores a value obtained by inserting binary "0100011" between each bit of the release number of the operating system 2 in binary into the keyword 2B, and then issues the keyword setting command 2.
A-1 is executed to set the keyword 2B in the keyword register IA in the central processing unit 1.

For example, if the release number of Operating System 2 is "11" in decimal, convert it to binary.
1011'', and between these bits there is “
0100011” respectively, it becomes “101000”.
1100100011101000111010001
A 32-bit value of ``1'' can be obtained, and this is set in the keyword register IA as the keyword 2B of the operating system 2 with release number ``11''.

When the support program 3 is executed after the setting of the keyword 2B to the keyword register IA is completed, the non-privileged subprogram 3A in the support program 3 starts execution. For example, if the support program 3 corresponds to the operating system 2 whose lease number is "11" in decimal, the non-privileged subprogram 3A
is 1010001100100011101000 using the same method as in Operating System 2.
After obtaining the 32-bit value "1110100011" and storing it in the keyword 3C, the privileged subprogram call instruction 3A- is used to obtain information on a specific control block.
1 to call the privileged subprogram 3B (step 21).

The privileged subprogram call instruction 3A-1 first calls the keyword 3C specified by the first operand and the central processing bag N.
Compare the contents of keyword register IA in l. If they match, change the privilege level to Privilege Level 2.
Transfers control to the address specified by the second operand. At this time, the address next to the second operand is stored as a return address in the non-privileged subprogram return address storage area 3D-1 in the stack-3D. As a result, the privileged subprogram 3B starts execution.

The privileged subprogram 3B stores information on a specific control block in use within the operating system 2 in the control block information storage area 3E (step 31). The privileged subprogram 3B finally executes the non-privileged subprogram return instruction 3B-1.

The non-privileged subprogram return instruction 3B-1 is a privileged subprogram in the non-privileged subprogram 3A stored in the non-privileged subprogram return address storage area 3D-1 in the stack 3D after changing the privilege level to the non-privileged level. Control is transferred to the address next to the program call instruction 3A-1. As a result, the non-privileged subprogram 3A is re-executed from this address, and the control block information stored in the control block information storage area 3E is displayed on the terminal screen (step 22).

On the other hand, if the keyword 3C specified by the first operand of the privileged subprogram call instruction 3A-1 and the contents of the keyword register IA in the central processing unit 1 do not match, the privileged subprogram 3B is called. It won't happen.

For example, if the support program 3 corresponds to the operating system 2 whose release number is "12" in decimal, the non-privileged subprogram 3A has the value of the keyword 3c "101000110010001".
11010001100100011'', so if the value of keyword 3c and the contents of keyword register IA do not match, privileged subprogram call instruction 3A-1 generates an interrupt for an illegal instruction and executes the instruction. and exit privileged subprogram 3.
Do not call B.

In this way, in the privileged program calling method of this embodiment, the support program 3, which has a close relationship with the operating system 2 and has a strong possibility of not being able to operate on an operating system with a different release number, can be used in an operating system with a different release number. can be prohibited from being used.

〔Effect of the invention〕

As explained above, the present invention provides a non-privileged subprogram that includes a privileged subprogram call instruction for calling a privileged subprogram, and a privileged subprogram that includes a non-privileged subprogram return instruction for returning to the non-privileged subprogram. Its use has the effect that it is not necessary to modify the operating system itself when enhancing support programs for performance measurement and debugging.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing an overview of the processing of the non-privileged subprogram shown in FIG. 1, and FIG. 3 is a flowchart showing an overview of subprogram processing. In the figure, 1...Central processing unit, IA...Keyword register, 2...Operating system, 2A...Keyword setting subprogram, 2A-To keyword setting instruction, 2B...Keyword, 3 ... Support program, 3A... Non-privileged subprogram, 3A-1. Privileged subprogram call instruction, 3B...
Privileged subprogram, 3B-1/Non-privileged subprogram return instruction, 3C...
Keywords: 3D: Stack; 3D-1: Non-privileged subprogram return address storage area; 3E: Control block information storage area.

Claims (2)

[Claims] (1) In a data processing system that uses a central processing unit that has a privileged level and a non-privileged level as a program execution environment, there are support programs that are started at a non-privileged level to support the development and maintenance of the operating system, etc. , a non-privileged subprogram that is built in this support program and includes a privileged subprogram call instruction for calling a privileged subprogram; and a non-privileged subprogram return instruction that is built in the support program and includes a privileged subprogram return instruction for returning to the non-privileged subprogram. A privileged program calling method comprising: the privileged subprogram; (2) The central processing unit has a keyword register for storing keywords, the operating system has a keyword setting subprogram including a keyword setting instruction for setting a keyword in the keyword register, and the privileged subprogram Privileged program calling according to claim 1, wherein a keyword specified by a program calling instruction is compared with a keyword set in the keyword register, and the privileged subprogram is called only when they match. method.