Modification of context saving functions

Patent metadata

Field	Value
Publication number	US-10496433-B2
Application number	US-201414552394-A
Country	US
Kind code	B2
Filing date	Nov 24, 2014
Priority date	Nov 24, 2014
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

A method for modifying a context saving function is disclosed. The method identifies a context saving function within a code fragment. The method further modifies the context saving function to determine a size of a register save buffer, allocate the register save buffer using the determined size, and save a register value in the register save buffer.

First claim

What is claimed is:

1. A method comprising:
identifying a context saving function within a code fragment; and
modifying, by a processing device, a portion of the code fragment corresponding to the context saving function to generate a modified context saving function to:
determine a size of a register save buffer where a register value indicative of a process state of a processing unit is stored in the register save buffer responsive to an execution of the context saving function;
allocate the register save buffer using the determined size;
save the register value in the register save buffer, wherein the register value is to restore the process state of the processing unit; and
provide an indication of the context saving function having been modified,

wherein the modified context saving function allows the context saving function associated with a fixed-size register save buffer used by a first processing architecture of the processing unit to be used by a second processing architecture that uses one or more additional processing unit registers.

2. The method of claim 1 , wherein modifying the context saving function further comprises:
inserting a function call to receive an indication of the size of the register save buffer.

3. The method of claim 1 , wherein modifying the context saving function further comprises:
modifying an initial part of a context switch to:
allocate the register save buffer; and
call a first system call to save process state data to the register save buffer.

4. The method of claim 1 , wherein modifying the context saving function further comprises:
modifying a final part of a context switch to:
call a second system call to restore the process state data from the register save buffer.

5. The method of claim 1 , wherein the register save buffer is an additional register save buffer distinct from the fixed-size register save buffer associated with the context switching function, and wherein the processing device is the same as the processing unit.

6. The method of claim 1 , wherein identifying the context saving function within a code fragment further comprises:
identifying an attribute of the code fragment indicating that the code fragment comprises a context switching function.

7. The method of claim 1 , wherein the code fragment comprises at least one of a source code, compiler-internal data structure, or an executable code.

8. The method of claim 1 , wherein modifying the context saving function is performed by a compiler.

9. The method of claim 1 , wherein modifying the context saving function is performed as a post-processing operation following a compilation.

10. A system comprising:
a memory; and
a processing device, operatively coupled with the memory, to:
identify a context saving function within a code fragment; and
modify a portion of the code fragment corresponding to the context saving function to generate a modified context saving function to:
determine a size of a register save buffer where a register value indicative of a process state of a processing unit is stored in the register save buffer responsive to an execution of the context saving function;
allocate the register save buffer using the determined size;
save the register value in the register save buffer, wherein the register value is to restore the process state of the processing unit; and
provide an indication of the context saving function having been modified,
wherein the modified context saving function allows the context saving function associated with a fixed-size register save buffer used by a first processing architecture of the processing unit to be used by a second processing architecture that uses one or more additional processing unit registers.

11. The system of claim 10 , wherein the processing device is further to:
insert a function call to determine the size of the register save buffer.

12. The system of claim 10 , wherein the processing device is further to:
modify an initial part of a context switch to:
allocate the register save buffer; and
call a first system call to save process state data to the register save buffer.

13. The system of claim 10 , wherein the processing device is further to:
modify a final part of a context switch to:
call a second system call to restore the process state data from the register save buffer.

14. A non-transitory computer readable storage medium including instructions that, when executed by a processing device, cause the processing device to:
identify a context saving function within a code fragment; and
modify, by the processing device, a portion of the code fragment corresponding to the context saving function to generate a modified context saving function to:
determine a size of a register save buffer where a register value of a process state of a processing unit is stored in the register save buffer responsive to an execution of the context saving function;
allocate the register save buffer using the determined size;
save the register value in the register save buffer, wherein the register value is to restore the process state of the processing unit; and
provide an indication of the context saving function having been modified,
wherein the modified context saving function allows the context saving function associated with a fixed-size register save buffer used by a first processing architecture of the processing unit to be used by a second processing architecture that uses one or more additional processing unit registers.

15. The non-transitory computer readable storage medium of claim 14 , wherein to modify the context saving function, the processing device is to:
insert a function call to receive the size of the register save buffer;
modify an initial part of a context switch to:
allocate the register save buffer; and
call a first system call to save process state data to the register save buffer; and modify a final part of a context switch to:
call a second system call to restore the process state data from the register save buffer.

Assignees

• Red Hat Inc

Inventors

• Weimer Florian

Classifications

• G06F8/76

  Adapting program code to run in a different environment; Porting · CPC title

• G06F9/547

  Remote procedure calls [RPC]; Web services · CPC title

• G06F9/461 Primary

  Saving or restoring of program or task context · CPC title

• G06F11/3466

  Performance evaluation by tracing or monitoring · CPC title