ARCHITECTURAL MODE CONFIGURATION

• US 20150269117A1
• Filed: 03/18/2014
• Published: 09/24/2015
• Est. Priority Date: 03/18/2014
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gainey, Charles W. Jr., Gschwind, Michael K.
• Granted Patent: US 9,582,295 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 15/76 Architectures of general purpose stored program computers with program plugboard G06F15/08; multicomputers G06F15/16
• CPC Class Codes: G06F 15/7867 with reconfigurable architecture
• CPC Class Codes: G06F 9/30076 to perform miscellaneous control operations, e.g. NOP
• CPC Class Codes: G06F 9/30189 according to execution mode, e.g. mode flag
• CPC Class Codes: G06F 9/4403 Processor initialisation
• CPC Class Codes: G06F 9/4405 Initialisation of multiprocessor systems
• CPC Class Codes: G06F 9/44505 Configuring for program initiating, e.g. using registry, configuration files

Abstract

A determination is made that a configuration architectural mode facility is installed in a computing environment that is configured for a plurality of architectural modes and has a defined power-on sequence that is to power-on the computing environment in one architectural mode of the plurality of architectural modes. Based on determining that the configuration architectural mode facility is installed, the computing environment is reconfigured to restrict use of the one architectural mode. The reconfiguring includes selecting a different power-on sequence to power-on the computing environment in another architectural mode of the plurality of architectural modes, wherein the another architectural mode is different from the one architectural mode, and executing the different power-on sequence to power-on the computing environment in the another architectural mode in place of the one architectural mode restricting use of the one architectural mode.

Claims

1. A computer program product for reconfiguring a computing environment, said computer program product comprising:

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

determining, by a processor, that a configuration architectural mode facility is installed in a computing environment that is configured for a plurality of architectural modes and has a defined power-on sequence that is to power-on the computing environment in one architectural mode of the plurality of architectural modes, the one architectural mode comprising a first instruction set architecture and having a first set of supported features;

based on determining that the configuration architectural mode facility is installed, reconfiguring, by the processor, the computing environment to restrict use of the one architectural mode, wherein the reconfiguring comprises;

selecting a different power-on sequence to power-on the computing environment in another architectural mode of the plurality of architectural modes, wherein the another architectural mode is different from the one architectural mode, and the another architectural mode comprises a second instruction set architecture and having a second set of supported features; and

executing the different power-on sequence to power-on the computing environment in the another architectural mode in place of the one architectural mode restricting use of the one architectural mode.

2. The computer program product of claim 1, wherein the executing the different power-on sequence comprises creating a new program status word to control operations of the computing environment in the another architectural mode, the creating the new program status word comprising inverting an architectural mode indicator in the new program status word to indicate the another architectural mode.

3. The computer program product of claim 2, wherein the creating the new program status word comprises forming the new program status word to have a format indicated by the another architectural mode, the format comprising expanding an address field from a first size to a second size, and performing the inverting of the architectural mode indicator.

4. The computer program product of claim 1, wherein the determining that the configuration architectural mode facility is installed comprises checking a facility indicator, the facility indicator to be set unconditionally or under control of a configuration indicator.

5. The computer program product of claim 1, wherein the reconfiguring further comprises disabling within the computing environment one or more operations to support the one architectural mode, the one or more operations comprising a switch operation to switch from the another architectural mode to the one architectural mode, wherein a switch back to the one architectural mode is disabled.

6. The computer program product of claim 5, wherein the disabling comprises altering processing of a signal processor instruction to provide an error based on a request to switch back to the one architectural mode.

7. The computer program product of claim 1, wherein the method further comprises performing a reset of at least one processor of the computing environment, wherein the performing the reset comprises:

resetting the computing environment in the another architectural mode, the resetting comprising setting an architectural mode of the computing environment to the another architectural mode; and

inverting an architectural mode indicator in a program status word to indicate the another architectural mode, the program status word used to control operations of the computing environment.

8. The computer program product of claim 1, wherein the reconfiguring comprises changing processing of a signal processor operation, wherein a signal processor operation to set an architectural mode of the computing environment to the architectural mode it is currently in results in storing status indicating the computing environment is currently in the architectural mode, this status being treated as acceptable by an issuer of the signal processor operation.

9. The computer program product of claim 1, wherein the one architectural mode is a legacy mode and the another architectural mode is an enhanced mode, and wherein the first set of supported features comprise 31-bit addressing and use of 32-bit general purpose registers, and the second set of supported features comprises 64-bit addressing and use of 64-bit general purpose registers.

10. The computer program product of claim 1, wherein the computing environment is a virtual guest environment having a host processor, a first guest virtual machine at a first level of virtualization, and a second guest virtual machine at a second level of virtualization, and wherein the reconfiguring is performed for the host processor and the first guest virtual machine, but not for the second guest virtual machine, the second guest virtual machine being initiated and processing in the one architectural mode.

11. A computer system for reconfiguring 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;

determining, by the processor, that a configuration architectural mode facility is installed in a computing environment that is configured for a plurality of architectural modes and has a defined power-on sequence that is to power-on the computing environment in one architectural mode of the plurality of architectural modes, the one architectural mode comprising a first instruction set architecture and having a first set of supported features;

based on determining that the configuration architectural mode facility is installed, reconfiguring, by the processor, the computing environment to restrict use of the one architectural mode, wherein the reconfiguring comprises;

selecting a different power-on sequence to power-on the computing environment in another architectural mode of the plurality of architectural modes, wherein the another architectural mode is different from the one architectural mode, and the another architectural mode comprises a second instruction set architecture and having a second set of supported features; and

executing the different power-on sequence to power-on the computing environment in the another architectural mode in place of the one architectural mode restricting use of the one architectural mode.

12. The computer system of claim 11, wherein the executing the different power-on sequence comprises creating a new program status word to control operations of the computing environment in the another architectural mode, the creating the new program status word comprising inverting an architectural mode indicator in the new program status word to indicate the another architectural mode.

13. The computer system of claim 12, wherein the creating the new program status word comprises forming the new program status word to have a format indicated by the another architectural mode, the format comprising expanding an address field from a first size to a second size, and performing the inverting of the architectural mode indicator.

14. The computer system of claim 11, wherein the reconfiguring further comprises disabling within the computing environment one or more operations to support the one architectural mode, the one or more operations comprising a switch operation to switch from the another architectural mode to the one architectural mode, wherein a switch back to the one architectural mode is disabled.

15. The computer system of claim 14, wherein the disabling comprises altering processing of a signal processor instruction to provide an error based on a request to switch back to the one architectural mode.

16. The computer system of claim 11, wherein the reconfiguring comprises changing processing of a signal processor operation, wherein a signal processor operation to set an architectural mode of the computing environment to the architectural mode it is currently in results in storing status indicating the computing environment is currently in the architectural mode, this status being treated as acceptable by an issuer of the signal processor operation.

17-19. -19. (canceled)

20. A computer program product for configuring a computing environment, said computer program product comprising:

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

configuring, by a processor, a computing environment to perform operations in a selected architectural mode, the configuring comprising;

commencing initialization of the computing environment using a stored program status word, the stored program status word having a format of an architectural mode different from the selected architectural mode;

determining that the stored program status word has the format of the architectural mode different from the selected architectural mode;

based on determining the stored program status word has the format of the architectural mode different from the selected architectural mode, automatically modifying the stored program status word to have a format of the selected architectural mode, the automatically modifying being performed absent an explicit request to switch to the selected architectural mode; and

completing initialization of the computing environment using the modified program status word to configure the computing environment in the selected architectural mode.