Methods and systems involving secure RAM

1. A system, comprising:

a processor;

a random access memory (RAM) coupled to the processor, the RAM divided into public RAM and secure RAM;

a system memory coupled to the processor, wherein the system memory stores RAM resize instructions that, when executed, enable the public RAM and the secure RAM to be dynamically resized; and

a cryptographic hardware accelerator (HWA), wherein the system memory stores save/restore secure RAM instructions that, when executed, perform a save operation that saves all secure RAM content to non-volatile memory and a restore operation that restores all secure RAM content from the non-volatile memory, and wherein the system memory stores HWA arbitration instructions that, when executed, enable the cryptographic HWA to operate in a secure mode and a public mode.

2. The system of claim 1 wherein, during a boot process of the system, the public RAM is selectively maximized while the secure RAM is minimized.

3. The system of claim 1 wherein, during run-time of the system, the public RAM is selectively minimized while the secure RAM is maximized.

4. The system of claim 1 wherein the RAM resize instructions determine at least one of an excess amount of public RAM and an excess amount of secure RAM.

5. The system of claim 4 wherein, if an excess amount of public RAM exists, the RAM resize instructions increase the amount of secure RAM and decrease the amount of public RAM in proportion to the amount of excess public RAM.

6. The system of claim 4 wherein, if an excess amount of secure RAM exists, the RAM resize instructions increase the amount of public RAM and decrease the amount of secure RAM in proportion to the amount of excess secure RAM.

7. The system of claim 1 wherein the RAM resize instructions cause the processor to perform a resize function selected from the group consisting of,

reconfiguring a firewall that divides the public RAM and the secure RAM;

cleaning memory that is switched from secure RAM to public RAM;

organizing memory heaps and variables in response to resized public RAM and secure RAM; and

organizing stacks and global variables to ensure dynamic resize of public RAM and secure RAM is possible.

8. A system, comprising:

a processor;

a cryptographic hardware accelerator (HWA) coupled to the processor; and

a system memory coupled to the processor, wherein the system memory stores HWA arbitration instructions that, when executed, enable the cryptographic HWA to be shared by a secure application and a public application;

wherein the system memory stores RAM resize instructions that, when executed, enable the public RAM portion and the secure RAM portion to be dynamically resized based on use; and

wherein the system memory stores save/restore secure RAM instructions that, when executed, saves the entire secure RAM portion to non-volatile memory before the system powers off and restores the entire secure RAM portion from the non-volatile memory when the system powers on again.

9. The system of claim 8 wherein the cryptographic HWA comprises HWA registers and wherein the HWA arbitration instructions, when executed, selectively set the HWA registers to a secure mode associated with the secure application and to a public mode associated with the public application.

10. The system of claim 9 wherein, during the secure mode, the HWA registers are only accessible to secure applications.

11. The system of claim 9 wherein, during the secure mode, the HWA arbitration instructions selectively save and restore content of the HWA registers.

12. The system of claim 9 wherein the HWA arbitration instructions, when executed, clean the HWA registers before switching from the secure mode to the public mode.

13. The system of claim 9 wherein, during the secure mode, the HWA arbitration instructions enable the cryptographic HWA to be shared by multiple secure applications.