Selectively controlling instruction execution in transactional processing

• US 9,983,881 B2
• Filed: 10/29/2014
• Issued: 05/29/2018
• Est. Priority Date: 06/15/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Greiner, Dan F., Jacobi, Christian, Rogers, Robert R., Slegel, Timothy J.
• Primary Examiner(s): Pham, Tuan A
• Application Number:
  US14/527,068
• Publication Number:
  US 20150052337A1
• Time in Patent Office: 1,308 Days
• Field of Search: 707688-704
• CPC Class Codes: G06F 9/3001 Arithmetic instructions
• CPC Class Codes: G06F 9/3004 to perform operations on memory
• CPC Class Codes: G06F 9/30047 Prefetch instructions; cache control instructions
• CPC Class Codes: G06F 9/30076 to perform miscellaneous control operations, e.g. NOP
• CPC Class Codes: G06F 9/30087 Synchronisation or serialisation instructions
• CPC Class Codes: G06F 9/30098 Register arrangements
• CPC Class Codes: G06F 9/30145 Instruction analysis, e.g. decoding, instruction word fields
• CPC Class Codes: G06F 9/30181 Instruction operation extension or modification
• CPC Class Codes: G06F 9/3834 Maintaining memory consistency
• CPC Class Codes: G06F 9/3861 Recovery, e.g. branch miss-prediction, exception handling error detection or correction G06F11/00
• CPC Class Codes: G06F 9/466 Transaction processing

Abstract

Execution of instructions in a transactional environment is selectively controlled. A TRANSACTION BEGIN instruction initiates a transaction and includes controls that selectively indicate whether certain types of instructions are permitted to execute within the transaction. The controls include one or more of an allow access register modification control and an allow floating point operation control.

Claims

1. A method of controlling execution of instructions within transactions of a computing environment, said method comprising:

obtaining, by a processor, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising;

an operation code to specify a transaction begin operation; and

at least one control to be used in controlling execution of one or more types of instructions in transactional processing;

executing, by the processor, the machine instruction, the executing comprising;

initiating a transaction; and

using a first control of the at least one control of the machine instruction to determine a first value, the first value to control execution within the transaction of an instruction of a first type, wherein the first control is an allow access register modification control, and wherein based on the first control being the allow access register modification control, the first type comprises instructions that modify one or more access registers, the allow access register modification control to be used to indicate whether the transaction is permitted to execute an instruction that modifies an access register that includes an indirect specification of an address space control element to be used in address translation; and

controlling execution of a particular instruction of the transactional processing based on the first value, the first value determined using the allow access register modification control.

2. The method of claim 1, wherein the using comprises performing a logical AND of the allow access register modification control of the machine instruction for a current nesting level of transactions of which the machine instruction is a part and outer nesting levels, if any, to determine the first value, the first value comprising an effective allow access register modification control.

3. The method of claim 1, wherein the at least one control further comprises a second control, the second control comprising an allow floating point operation control to be used to indicate whether the transaction is permitted to execute specified floating point instructions.

4. The method of claim 1, further comprising:

obtaining, by the processor, an instruction within the transaction initiated by the transaction begin operation;

determining by the processor based on at least one value computed based on the at least one control whether the obtained instruction is an instruction to be prohibited from execution; and

executing the obtained instruction based on the determining indicating the instruction is not to be prohibited from execution.

5. The method of claim 1, wherein the transaction is part of a nest of transactions, and wherein the method further comprises re-determining the first value based on termination of a transaction of the nest of transactions.

6. The method of claim 1, wherein the transaction comprises a nonconstrained transaction.

7. The method of claim 1, wherein the transaction comprises a constrained transaction.

8. The method of claim 1, wherein the one or more types of instructions comprises specified floating point instructions or instructions that modify the access register.

9. A computer program product for controlling execution of instructions within transactions of a computing environment, said computer program product comprising:

a non-transitory computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

obtaining, by a processor, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising;

an operation code to specify a transaction begin operation; and

at least one control to be used in controlling execution of one or more types of instructions in transactional processing;

executing, by the processor, the machine instruction, the executing comprising;

initiating a transaction; and

using a first control of the at least one control of the machine instruction to determine a first value, the first value to control execution within the transaction of an instruction of a first type, wherein the first control is an allow access register modification control, and wherein based on the first control being the allow access register modification control, the first type comprises instructions that modify one or more access registers, the allow access register modification control to be used to indicate whether the transaction is permitted to execute an instruction that modifies an access register that includes an indirect specification of an address space control element to be used in address translation; and

controlling execution of a particular instruction of the transactional processing based on the first value, the first value determined using the allow access register modification control.

10. The computer program product of claim 9, wherein the using comprises performing a logical AND of the allow access register modification control of the machine instruction for a current nesting level of transactions of which the machine instruction is a part and outer nesting levels, if any, to determine the first value, the first value comprising an effective allow access register modification control.

11. The computer program product of claim 9, wherein the at least one control further comprises a second control, the second control comprising an allow floating point operation control to be used to indicate whether the transaction is permitted to execute specified floating point instructions.

12. The computer program product of claim 9, wherein the method further comprises:

obtaining, by the processor, an instruction within the transaction initiated by the transaction begin operation;

determining by the processor based on at least one value computed based on the at least one control whether the obtained instruction is an instruction to be prohibited from execution; and

executing the obtained instruction based on the determining indicating the instruction is not to be prohibited from execution.

13. The computer program product of claim 9, wherein the transaction is part of a nest of transactions, and wherein the method further comprises re-determining the first value based on termination of a transaction of the nest of transactions.

14. The computer program product of claim 9, wherein the one or more types of instructions comprises specified floating point instructions or instructions that modify the access register.

15. A computer system for controlling execution of instructions within transactions of a computing environment, said computer system comprising:

a memory; and

a processor in communications with the memory, wherein the computer system is configured to perform a method, said method comprising;

obtaining, by the processor, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising;

an operation code to specify a transaction begin operation; and

at least one control to be used in controlling execution of one or more types of instructions in transactional processing;

executing, by the processor, the machine instruction, the executing comprising;

initiating a transaction; and

using a first control of the at least one control of the machine instruction to determine a first value, the first value to control execution within the transaction of an instruction of a first type, wherein the first control is an allow access register modification control, and wherein based on the first control being the allow access register modification control, the first type comprises instructions that modify one or more access registers, the allow access register modification control to be used to indicate whether the transaction is permitted to execute an instruction that modifies an access register that includes an indirect specification of an address space control element to be used in address translation; and

controlling execution of a particular instruction of the transactional processing based on the first value, the first value determined using the allow access register modification control.

16. The computer system of claim 15, wherein the using comprises performing a logical AND of the allow access register modification control of the machine instruction for a current nesting level of transactions of which the machine instruction is a part and outer nesting levels, if any, to determine the first value, the first value comprising an effective allow access register modification control.

17. The computer system of claim 15, wherein the at least one control further comprises a second control, the second control comprising an allow floating point operation control to be used to indicate whether the transaction is permitted to execute specified floating point instructions.

18. The computer system of claim 15, wherein the method further comprises:

obtaining, by the processor, an instruction within the transaction initiated by the transaction begin operation;

determining by the processor based on at least one value computed based on the at least one control whether the obtained instruction is an instruction to be prohibited from execution; and

executing the obtained instruction based on the determining indicating the instruction is not to be prohibited from execution.

19. The computer system of claim 15, wherein the transaction is part of a nest of transactions, and wherein the method further comprises re-determining the first value based on termination of a transaction of the nest of transactions.

20. The computer system of claim 15, wherein the one or more types of instructions comprises specified floating point instructions or instructions that modify the access register.