Field repairable logic
A state matcher for a logic circuit may detect at least one of a buggy state of the logic circuit, a precursor to a buggy state of the logic circuit and a verified state of the logic circuit based on a plurality of signal values indicative of a state of the logic circuit. A recovery controller for a microprocessor may reconfigure the microprocessor to a trusted feature mode in response to receiving a signal indicating that the microprocessor is in a predefined state and operate the microprocessor in the trusted feature mode for a predetermined period of time.
1. A method for state matching and recovering a microprocessor, the method comprising:
sampling a plurality of signal values indicative of at least one state of the microprocessor;
comparing at least some of the signal values with one or more signatures of signal values each representing one or more precursors to an untrusted state of the microprocessor;
determining whether the at least one state of the microprocessor is in one of the precursors to the untrusted state based on the comparing; and
initiating reconfiguration of the microprocessor to a trusted state in response to the at least one state of the microprocessor being in one of the precursors to the untrusted state.
2. The method of claim 1 further comprising loading storage cells with the one or more signatures of signal values.
3. The method of claim 1 wherein the at least one state of the microprocessor comprises a microarchitectural state of the microprocessor or a logic circuit state of the microprocessor.
4. A recovery controller for a microprocessor comprising:
a logic block configured to
receive a triggering signal (i) that results from a comparison of sampled signal values indicative of a state of the microprocessor with one or more signatures of signal values each representing one or more precursors to an untrusted state of the microprocessor, and (ii) that indicates that the microprocessor is in one of the precursors to the untrusted state,
initiate reconfiguration of the microprocessor to a trusted feature mode in response to the triggering signal, and
operate the microprocessor in the trusted feature mode for a period of time to avoid the untrusted state.
5. The recovery controller of claim 4 wherein the logic block is further configured to reconfigure the microprocessor to a full feature mode after the period of time.
6. A method for controlling a logic circuit comprising:
sampling a plurality of signal values indicative of a state of the logic circuit;
initiating reconfiguration of the logic circuit to a trusted feature mode in response to a comparison of at least some of the signal values with one or more signatures of signal values, each representing one or more precursors to an untrusted state of the logic circuit, indicating that the state of the logic circuit is a precursor to an untrusted state; and
operating the logic circuit in the trusted feature mode for a predetermined period of time.
7. The method of claim 6 further comprising reconfiguring the logic circuit to a full feature mode after the predetermined period of time.
8. A state matcher for a logic circuit comprising:
a logic block configured to detect a precursor to an untrusted state of the logic circuit based on a comparison of sampled signal values indicative of a state of the logic circuit with one or more signatures of signal values each representing one or more precursors to the untrusted state of the logic circuit, and to initiate reconfiguration of the logic circuit to a trusted feature mode.
9. A recovery controller for a microprocessor comprising:
a logic block configured to,
detect a precursor to an untrusted state of the microprocessor based on a comparison of sampled signal values indicative of a state of the microprocessor with one or more signatures of signal values each representing one or more precursors to the untrusted state of the microprocessor,
reconfigure the microprocessor to a trusted feature mode in response to the detecting, and
operate the microprocessor in the trusted feature mode for a predetermined period of time.