Method and apparatus for pipeline inclusion tracking

A computer processor comprising:

• an instruction cache to store instruction fetched upon branch predictions in a pipeline of the computer processor;
• and
• a buffer coupled to the instruction cache, the buffer is to support a plurality of groups, a group within the plurality of groups to support a plurality of entries, an entry within a respective group to support tracking of a plurality of cache lines in the instruction cache, and a cache line of the plurality of cache lines to store instructions, wherein the respective group identifies a youngest branch identifier (ID) and an oldest branch ID corresponding to a youngest instruction and an oldest instruction tracked by the respective group, respectively, upon a lookup request, the buffer to perform lookup in one group that is currently available to track the fetched instructions, wherein responsive to a matching entry for an instruction being found in the one group, the youngest branch ID of the one group is to be updated with a corresponding branch ID of the instruction, and responsive to no matching entry being found for the instruction in the one group, a matching entry is to be added for the instruction in the one group to track a cache line in the instruction cache corresponding to the instruction and updating the youngest branch ID of the one group with a corresponding branch ID of the instruction, and responsive to a detection of dynamic code modification violation affecting a cache line tracked by an entry in the buffer, flushing non-retired instructions in the pipeline.

A non-transitory machine-readable storage medium storing instructions that when executed by a processor, are capable of causing the processor to perform:

• looking up a buffer to find entries to track fetched instructions in a pipeline of a processor, the buffer to support a plurality of groups each to support a plurality of entries, an entry within a respective group to support tracking of a plurality of cache lines in an instruction cache, and a cache line of the plurality of cache lines to store instructions, wherein the respective group identifies a youngest branch identifier (ID) and an oldest branch ID corresponding to a youngest instruction and an oldest instruction, respectively, and wherein the looking up is performed in one group that is currently available to track the fetched instructions;
• responsive to a matching entry for an instruction being found in the one group, updating the youngest branch ID of the one group with a corresponding branch ID of the instruction;
• and
• responsive to a detection of dynamic code modification violation affecting a cache line tracked by an entry in the buffer, flushing non-retired instructions from the pipeline.