EFFICIENT STORAGE OF MEMORY VERSION DATA

• US 20130013843A1
• Filed: 07/07/2011
• Published: 01/10/2013
• Est. Priority Date: 07/07/2011
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Radovic, Zoran, Murphy, Graham Ricketson, Daga, Bharat K.
• Granted Patent: US 8,756,363 B2
• Time in Patent Office: Days
• US Class Current: 711/5
• CPC Class Codes: G06F 11/073 in a memory management context, e.g. virtual memory or cache management memory management G06F12/00; testing of static memory units G11C29/00
• CPC Class Codes: G06F 11/0763 by bit configuration check, e.g. of formats or tags
• CPC Class Codes: G06F 11/1666 where the redundant component is memory or memory area
• CPC Class Codes: G06F 21/52 during program execution, e.g. stack integrity ; Preventing unwanted data erasure; Buffer overflow

Abstract

Systems and methods for efficient memory corruption detection in a processor. A processor detects a first data structure is to be allocated in a physical memory. The physical memory may be a DRAM with a spare bank of memory reserved for a hardware failover mechanism. Either the processor or an operating system (OS) determines a first version number corresponding to the first data structure. During initialization of the first data structure, the first version number may be stored in a first location in the spare bank. The processor receives from the OS a pointer holding the first version number. When the processor executes memory access operations targeting the first data structure, the processor compares the first version number with a third version number stored in a location in the physical memory indicated by the memory access address. The processor may set a trap in response to determining a mismatch.

Claims

1. A computing system comprising:

a processor;

a physical memory coupled to the processor; and

an operating system (OS);

wherein the processor is configured to;

detect a first data structure is to be allocated in the physical memory;

send an indication to the OS to allocate the first data structure in the physical memory;

receive from the OS a pointer indicating a first location in the physical memory where the first data structure is stored;

associate a first version number with the first data structure; and

store the first version number in a second location in the physical memory, wherein the second location is associated with the first location.

2. The computing system as recited in claim 1, wherein the physical memory comprises a plurality of banks, and wherein the first data structure is stored in a first bank of the plurality of banks, and the first version number is stored in a spare bank corresponding to the first bank.

3. The computing system as recited in claim 2, wherein in response to a new memory allocation, the processor is configured to associate a new version number with the new memory allocation, wherein the new version number is different from a version number associated with a most recent memory allocation.

4. The computing system as recited in claim 2, wherein said pointer includes a subset of bits which are used for identifying a memory location, and one or more bits which are unused for purposes of identifying the memory location, and wherein the processor is configured to use the one or more bits to convey the first version number.

5. The computing system as recited in claim 4, wherein when accessing the first data structure, the processor is further configured to:

compare an expected version number to a version number stored with the first data structure; and

detect an error in response to determining the expected version number does not match the version number stored with the first data structure.

6. The computing system as recited in claim 5, wherein the processor is further configured to generate an indication of an error in response to detecting said error.

7. The computing system as recited in claim 5, wherein the processor is configured to generate said indication of an error in further response to detecting a memory corruption detection state is enabled.

8. The computing system as recited in claim 7, wherein the error-reporting condition further comprises a determination the physical memory does not hold a value indicating a hardware failure occurred in a portion of the physical memory corresponding to the first data structure.

9. A method for a processor, the method comprising:

detecting a first data structure is to be allocated in the physical memory;

determining a first version number corresponding to the first data structure;

sending an indication to the OS to allocate the first data structure in the physical memory;

receiving from the OS a pointer indicating a first location in the physical memory where the first data structure is stored;

associating a first version number with the first data structure; and

storing the first version number in a second location in the physical memory, wherein the second location is associated with the first location.

10. The method as recited in claim 9, wherein the physical memory comprises a plurality of banks, and wherein the first data structure is stored in a first bank of the plurality of banks, and the first version number is stored in a spare bank corresponding to the first bank.

11. The method as recited in claim 10, wherein in response to a new memory allocation, the method further comprises associating a new version number with the new memory allocation, wherein the new version number is different from a version number associated with a most recent memory allocation.

12. The method as recited in claim 10, wherein said pointer includes a subset of bits which are used for identifying a memory location, and one or more bits which are unused for purposes of identifying the memory location, and wherein the method comprises using the one or more bits to convey the first version number.

13. The method as recited in claim 12, wherein when accessing the first data structure, the method further comprises:

comparing an expected version number to a version number stored with the first data structure; and

detecting an error in response to determining the expected version number does not match the version number stored with the first data structure.

14. The method as recited in claim 13, further comprising generating an indication of an error in response to detecting said error.

15. The method as recited in claim 13, wherein the error-reporting condition comprises at least a memory corruption detection state is enabled.

16. The method as recited in claim 15, generating said indication of an error in further response to detecting a memory corruption detection state is enabled.

17. A processor comprising:

a first interface to a memory subsystem comprising at least a physical memory;

a second interface to an operating system (OS);

a multi-stage pipeline for executing instructions received via the first interface; and

circuitry;

wherein the circuitry is configured to;

detect a first data structure is to be allocated in the physical memory;

send an indication to the OS to allocate the first data structure in the physical memory;

receive from the OS a pointer indicating a first location in the physical memory where the first data structure is stored;

associate a first version number with the first data structure; and

store the first version number in a second location in the physical memory, wherein the second location is associated with the first location.

18. The processor as recited in claim 17, wherein the physical memory comprises a plurality of banks, and wherein the first data structure is stored in a first bank of the plurality of banks, and the first version number is stored in a spare bank corresponding to the first bank.

19. The processor as recited in claim 18, wherein in response to a new memory allocation, the processor is configured to associate a new version number with the new memory allocation, wherein the new version number is different from a version number associated with a most recent memory allocation.

20. The processor as recited in claim 19, wherein said pointer includes a subset of bits which are used for identifying a memory location, and one or more bits which are unused for purposes of identifying the memory location, and wherein the processor is configured to use the one or more bits to convey the first version number.