PC-Based Instruction Group Permissions

A method, comprising:

• receiving, in a processor of a computer system, a particular instruction of an instruction set architecture (ISA) of the processor, the particular instruction being located at a first memory address of a memory of the computer system;
• storing, by the processor in a permission table, a plurality of secondary execution privileges that define, for instructions stored at different memory locations, which of a plurality of instruction groups of the ISA are executable from those memory locations;
• generating, by the processor based on a first value corresponding to the first memory address, a particular secondary execution privileges index for the particular instruction;
• retrieving, by the processor from the permission table using the particular secondary execution privileges index, a particular secondary execution privileges value corresponding to the first memory address;
• and
• determining, by the processor based on the particular secondary execution privileges value and the particular instruction, whether to permit execution of the particular instruction.

An apparatus, comprising:

• a processor configured to:
• receive, at an execution pipeline, a particular instruction for execution, the particular instruction being located at a first virtual memory address;
• access, using the first virtual memory address, an entry of a page table, the entry storing a physical page number to which the first virtual memory address maps and an indication of a particular secondary execution privileges value that specifies which of a plurality of instruction groups of an instruction set architecture (ISA) of the processor are permitted to be executed at the first virtual memory address;
• and
• determine, based on the particular secondary execution privileges value and a determination of which instruction group the particular instruction belongs to, whether to permit execution of the particular instruction.