Semiconductor circuit device and method of detecting runaway
View Patent ↗In an embodiment of the invention, if a microprocessor detects runaway of a CPU executing a program, it starts a recovery program. The runaway in the program execution is detected by monitoring accesses a non-implementation space in a program space. If the CPU accesses any address in the non-implementation space, the microprocessor sends an instruction to the CPU to execute a predetermined recovery program. Thereby, the microprocessor can detect and stop the runaway into the non-implementation space.
1. A semiconductor circuit device for detecting runaway of program execution in a processor comprising:
a processor executing a process according to a program;
an address determination section determining an address of a program space accessed by the processor;
an instruction section outputting a predetermined recovery program in response to a determination by said address determination section; and
an output control section selecting one of a result accessed by the address and the predetermined recovery program in response to the determination of the address determination section, and outputting the selected one to the processor,
wherein the output control section selects the predetermined recovery program when the address determination section determines that the address is a non-implementation space,
wherein the address determination section determines whether the processor has accessed addresses in a part of the non-implementation space, and
wherein a non-branching instruction is put out to the processor if the processor has accessed to an address in the non-implementation space outside of the part of the non-implementation space.
2. The semiconductor circuit device according to claim 1 , wherein
the address determination section determines whether the processor has accessed any of all of the addresses in the non-implementation space, and
the instruction section outputting the predetermined program in response to the determination of the address determination section that the processor has accessed any of the addresses in the non-implementation space.
3. The semiconductor circuit device according to claim 1 , wherein the instruction section outputs an interrupt request as the predetermined recovery program.
4. The semiconductor circuit device according to claim 1 , wherein the instruction section further comprises a register allocated to one or more of addresses in the non-implementation space, and provides an instruction stored in the register to the processor in response to the determination of the address determination section that the processor has accessed the one or more addresses.
5. The semiconductor circuit device according to claim 4 , wherein the register is allocated to all of the addresses in the non-implementation space.
6. The semiconductor circuit device according to claim 1 , wherein
the non-implementation space comprises a plurality of segments,
the instruction section comprises a plurality of registers each of which stores a predetermined recovery program,
each of the plurality of segments is allocated to one of the plurality of registers, and
the instruction section provides the processor with an instruction stored in the register corresponding to the address which the processor has accessed.
7. A runaway detection method for detecting runaway of program execution in a processor which carries out processes according to a program comprising:
determining an address of a program space accessed by the processor,
determining whether the address is in a first part of a non-implementation space of the program space or a second part thereof that is separate from the first part,
carrying out a predetermined recovery process in response to a determination that the address is in the first part of the non-implementation space, and
sending a non-branching instruction to the processor in response to the determination that the address is in the second part of the non-implementation space.
8. The runaway detection method according to claim 7 , wherein it is determined that the processor has accessed the first part of the non-implementation space if any one address of the first part of the non-implementation space has been accessed.
9. The runaway detection method according to claim 7 , wherein
the processor is instructed to invoke a predetermined recovery program in response to a determination that the first part of the non-implementation space has been accessed, and
the predetermined recovery program execution is started in the processor in response to the instruction.
10. The runaway detection method according to claim 9 , wherein
the processor is instructed to invoke the recovery program by an instruction corresponding to the accessed address in the first part of the non-implementation space, and
the recovery program indicated by the instruction started in the processor.
11. The runaway detection method according to claim 10 , wherein the instruction is allocated to a plurality of addresses in the first part of the non-implementation space.
12. The runaway detection method according to claim 9 , wherein
all addresses in the first part of the non-implementation space are allocated to one or more instructions,
an instruction corresponding to the accessed address in the first part of the non-implementation space instructs the processor to invoke the recovery program, and
the recovery program indicated in the instruction is started in the processor.
13. The runaway detection method according to claim 9 , wherein the processor is instructed to invoke the predetermined recovery program by an interrupt request.