Pipeline processor execution stages, secure emulation logic, gating debug/profile output
The present disclosure describes systems and methods for controlling access to secure debugging and profiling features of a computer system. Some illustrative embodiments include a system that includes a processor, and a memory coupled to the processor (the memory used to store information and an attribute associated with the stored information). At least one bit of the attribute determines a security level, selected from a plurality of security levels, of the stored information associated with the attribute. Asserting at least one other bit of the attribute enables exportation of the stored information from the computer system if the security level of the stored information is higher than at least one other security level of the plurality of security levels.
1. A pipeline processor comprising:
A. a first pipeline processor stage including:
i. a first instruction execution stage having a first instruction input and a first instruction output, and executing instructions received on the first instruction input;
ii. a first secure emulation logic, corresponding to the first execution stage, having first security inputs and first security outputs, the first secure emulation logic including a first register for storing a non-secure bit and a secure emulation bit for each instruction received by the first instruction execution stage; and
iii. first gating circuitry having a first input coupled with the a non-secure bit and the secure emulation bit of the first register, a second input coupled with the first instruction execution stage, and a first processor stage debug/profile output; and
B. a second pipeline processor stage including:
i. a second instruction execution stage having a second instruction input coupled to the first instruction output and a second instruction output, and executing instructions received on the second instruction input;
ii. a second secure emulation logic, corresponding to the second execution stage, having second security inputs coupled to the first security outputs, and second security outputs, the second secure emulation logic including a second register storing a non-secure bit and a secure emulation bit for each instruction received by the second instruction execution stage; and
iii. second gating circuitry having a first input coupled with the a non-secure bit and the secure emulation bit of the second register, a second input coupled with the second instruction execution stage, and a second processor stage debug/profile output.
2. The pipeline processor of claim 1 including test interface circuitry having processor debug/profile inputs coupled to the first processor stage debug/profile output and the second processor stage debug/profile output.
3. The pipeline processor of claim 1 including memory circuitry having instruction outputs coupled with the first instruction inputs of the first instruction execution stage and having security outputs coupled with the first security inputs of the first secure emulation logic, the memory circuitry including a program instruction portion coupled with the instruction outputs and a page attribute table portion for the program instruction coupled to the security outputs.
4. The pipeline processor of claim 3 including a memory controller coupled between the memory circuitry and the first pipeline processor stage.
5. The pipeline processor of claim 1 in which the first gating circuitry includes an AND gate and the second gating circuitry includes an AND gate.
6. The pipeline processor of claim 3 in which the page attribute table portion includes a non-secure bit and an emulation bit for each instruction.
7. The pipeline processor of claim 3 in which the memory circuitry includes first cache memory having a program portion for cached program instructions, cached program tag information, and a cached program page attribute table for the cached program instructions.
8. The pipeline processor of claim 7 in which the memory circuitry includes second cache memory coupled with the first cache memory, the second cache memory having a program portion for cached program instructions, cached program tag information, and a cached program page attribute table for the cached program instructions.
9. The pipeline processor of claim 8 in which the memory circuitry includes main memory coupled with the second cache memory, the main memory having a program portion for cached program instructions and a cached program page attribute table for the cached program instructions.