RUN-TIME INSTRUMENTATION OF GUARDED STORAGE EVENT PROCESSING

• US 20180203633A1
• Filed: 01/19/2017
• Published: 07/19/2018
• Est. Priority Date: 01/19/2017
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Greiner, Dan F., Jacobi, Christian, Saporito, Anthony, Shum, Chung-Lung K., Slegel, Timothy J.
• Granted Patent: US 10,496,311 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 11/0724 in a multiprocessor or a multi-core unit multiprocessors per se G06F15/80
• CPC Class Codes: G06F 11/0775 Content or structure details of the error report, e.g. specific table structure, specific error fields
• CPC Class Codes: G06F 11/3024 where the computing system component is a central processing unit [CPU]
• CPC Class Codes: G06F 11/3055 Monitoring arrangements for monitoring the status of the computing system or of the computing system component, e.g. monitoring if the computing system is on, off, available, not available error or fault processing without redundancy G06F11/0703; error detection or correction by redundancy in data representation G06F11/08; error detection or correction by redundancy in operation G06F11/14; error detection or correction by redundancy in hardware G06F11/16
• CPC Class Codes: G06F 11/3612 by runtime analysis performance monitoring G06F11/3466
• CPC Class Codes: G06F 11/3636 by tracing the execution of the program
• CPC Class Codes: G06F 12/0253 Garbage collection, i.e. reclamation of unreferenced memory
• CPC Class Codes: G06F 12/0857 by multiple requestors
• CPC Class Codes: G06F 12/1441 for a range
• CPC Class Codes: G06F 2212/1052 Security improvement
• CPC Class Codes: G06F 3/0622 in relation to access
• CPC Class Codes: G06F 3/0637 Permissions
• CPC Class Codes: G06F 3/0673 Single storage device
• CPC Class Codes: G06F 9/30076 to perform miscellaneous control operations, e.g. NOP
• CPC Class Codes: G06F 9/3834 Maintaining memory consistency
• CPC Class Codes: G06F 9/3842 Speculative instruction execution
• CPC Class Codes: G06F 9/467 Transactional memory G06F9/528 takes precedence

Abstract

A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Claims

1. A computer program product for facilitating processing in a computing environment, said computer program product comprising:

a computer readable storage medium readable by a processing circuit and storing instructions for performing a method comprising;

executing an instruction that results in recognition of a guarded storage event, wherein the guarded storage event occurs based on attempting access to an address in a guarded section of storage defined by a boundary indicating a range of addresses that are guarded, the guarded storage event protecting addresses within the boundary, wherein a load operation by the instruction from addresses within the guarded section is prevented; and

creating a guarded storage event record, based on executing the instruction that results in recognition of the guarded storage event, the guarded storage event record including an indication of the instruction resulting in recognition of the guarded storage event.

2. The computer program product of claim 1, wherein the instruction is a load guarded instruction, the load guarded instruction used to determine whether the guarded storage event exists, and wherein based on a selected operand of the instruction not designating the guarded section, the instruction performs the load operation, and based on the selected operand designating the guarded section, control branches to a guarded storage event handler and the load operation is not performed.

3. The computer program product of claim 1, wherein the instruction is a load logical and shift guarded instruction, the load logical and shift guarded instruction used to determine whether the guarded storage event exists, and wherein based on a selected operand of the instruction not designating the guarded section, the instruction performs the load operation, and based on the selected operand designating the guarded section, control branches to a guarded storage event handler and the load operation is not performed.

4. The computer program product of claim 1, wherein the guarded storage event record further includes a location of a guarded storage event handler instruction of a guarded storage event handler used to manage the guarded storage event.

5. The computer program product of claim 1, wherein the guarded storage event record further includes a code to indicate how the indication of the instruction is stored in the guarded storage event record.

6. The computer program product of claim 1, wherein the method further comprises placing the guarded storage event record in a collection buffer, the collection buffer used to capture a set of records that report on one or more events of a processor during program execution.

7. The computer program product of claim 1, wherein the method further comprises creating an instruction record identifying a sampled instruction and indicating whether a guarded storage facility is enabled.

8. The computer program product of claim 7, wherein the creating the instruction record precedes creating the guarded storage event record.

9. The computer program product of claim 7, wherein the method further comprises performing sampling of instructions executing within the computing environment to determine the sampled instruction, and wherein the instruction record is created based on determining the sampled instruction.

10. The computer program product of claim 9, wherein the sampled instruction is a load instruction used to perform a load operation that is defined to identify a guarded area of memory.

11. A computer system for facilitating processing in a computing environment, said computer system comprising:

a memory; and

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

executing an instruction that results in recognition of a guarded storage event, wherein the guarded storage event occurs based on attempting access to an address in a guarded section of storage defined by a boundary indicating a range of addresses that are guarded, the guarded storage event protecting addresses within the boundary, wherein a load operation by the instruction from addresses within the guarded section is prevented; and

creating a guarded storage event record, based on executing the instruction that results in recognition of the guarded storage event, the guarded storage event record including an indication of the instruction resulting in recognition of the guarded storage event.

12. The computer system of claim 11, wherein the guarded storage event record further includes a location of a guarded storage event handler instruction of a guarded storage event handler used to manage the guarded storage event.

13. The computer system of claim 11, wherein the guarded storage event record further includes a code to indicate how the indication of the instruction is stored in the guarded storage event record.

14. The computer system of claim 11, wherein the method further comprises creating an instruction record identifying a sampled instruction and indicating whether a guarded storage facility is enabled.

15. The computer system of claim 14, wherein the method further comprises performing sampling of instructions executing within the computing environment to determine the sampled instruction, and wherein the instruction record is created based on determining the sampled instruction.

16. A computer-implemented method of facilitating processing in a computing environment, said computer-implemented method comprising:

executing an instruction that results in recognition of a guarded storage event, wherein the guarded storage event occurs based on attempting access to an address in a guarded section of storage defined by a boundary indicating a range of addresses that are guarded, the guarded storage event protecting addresses within the boundary, wherein a load operation by the instruction from addresses within the guarded section is prevented; and

creating, by a processor, a guarded storage event record, based on executing the instruction that results in recognition of the guarded storage event, the guarded storage event record including an indication of the instruction resulting in recognition of the guarded storage event.

17. The computer-implemented method of claim 16, wherein the guarded storage event record further includes a location of a guarded storage event handler instruction of a guarded storage event handler used to manage the guarded storage event.

18. The computer-implemented method of claim 16, wherein the guarded storage event record further includes a code to indicate how the indication of the instruction is stored in the guarded storage event record.

19. The computer-implemented method of claim 16, further comprising creating an instruction record identifying a sampled instruction and indicating whether guarded storage facility is enabled.

20. The computer-implemented method of claim 19, further comprising performing sampling of instructions executing within the computing environment to determine the sampled instruction, and wherein the instruction record is created based on determining the sampled instruction.