Microprocessor that facilitates task switching between encrypted and unencrypted programs
US8886960B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2013 |
| Grant date | Nov 11, 2014 |
| Priority date | — |
| Expiry date | Oct 29, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/20
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A microprocessor includes an architected register having a bit. The microprocessor sets the bit. The microprocessor also includes a fetch unit that fetches encrypted instructions from an instruction cache and decrypts them prior to executing them, in response to the microprocessor setting the bit. The microprocessor saves the value of the bit to a stack in memory and then clears the bit, in response to receiving an interrupt. The fetch unit fetches unencrypted instructions from the instruction cache and executes them without decrypting them, after the microprocessor clears the bit. The microprocessor restores the saved value from the stack in memory to the bit in the architected register, in response to executing a return from interrupt instruction. The fetch unit resumes fetching and decrypting the encrypted instructions, in response to determining that the restored value of the bit is set.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.