Processor, data processing system and method for synchronzing access to data in shared memory

A data processing system, comprising:

• a system memory;
• a system interconnect;
• and
• a plurality of processing units coupled to the system interconnect, at least a particular processing unit among said plurality of processing units including:
• a processor core including:
• a store-through upper level cache;
• an instruction sequencing unit that fetches instructions for execution;
• a data register;
• at least one instruction execution unit coupled to said instruction sequencing unit, wherein the at least one instruction execution unit, responsive to receipt of a load-reserve instruction from said instruction sequencing unit, executes said load-reserve instruction to determine a load target address;
• and
• wherein the processor core, responsive to the execution of the load-reserve instruction, performs a corresponding load-reserve operation by accessing said store-through upper level cache utilizing said load target address to cause data associated with said load target address to be loaded from said store-through upper level cache into said data register and by establishing a reservation for a reservation granule including the load target address.

A method of data processing in a data processing system including a memory hierarchy including a store-though upper level cache, a lower level cache and a system memory, said method comprising:

• in response to receipt of a load-reserve instruction, an execution unit executing said load-reserve instruction to determine a load target address;
• in response to execution of the load-reserve instruction, performing a corresponding load-reserve operation, wherein performing the load-reserve operation includes:
• accessing the store-through upper level cache utilizing said load target address to cause data associated with said load target address to be loaded from the store-through upper level cache into a data register;
• and
• establishing, at the lower level cache, a reservation for a reservation granule including the load target address.