Apparatuses and methods of data processing are disclosed for tagging instructions on-line. Instruction tag storage stores information indicative of a tag applied to certain instruction identifiers. A data processing operation performed by the data processing circuitry in response to an executed instruction is dependent on whether there is a corresponding instruction identifier for the executed instruction in the instruction tag storage which has the instruction tag. Register writer storage is maintained, and an entry is created for each register writing instruction encountered which causes a result value to be written to a destination register, where the entry comprises an indication of the destination register and the register writing instruction. An instruction tagging queue buffers instruction identifiers and an instruction identifier is added to the queue for a predetermined type of instruction when it is encountered. Instruction tagging circuitry tags the instructions in the instruction tagging queue and determines one or more producer instructions which each produce at least one data value which is a source operand of a subject instruction and adds the one or more producer instructions to the instruction tagging queue. Data dependency graphs are thus elaborated and online tagging of such data dependency graphs is thus supported.

Dynamic hammock branch training for branch hammock detection in an instruction stream executing in a processor is disclosed. A branch hammock detection circuit is configured to dynamically detect branch hammocks in an instruction stream during run-time processing of the instruction stream. In response to an identified conditional branch instruction, the branch hammock detection circuit starts a training process for a potential branch hammock predicated by the conditional branch instruction. The branch hammock detection circuit is configured to determine if an identified in-training branch hammock is an actual branch hammock based on setting a potential convergence point as the target address for the conditional branch instruction based on whether the branch is taken or not taken. If an instruction is processed at the set convergence point, this means the set convergence point can be an actual convergence point and the in-training branch hammock can be detected as an actual branch hammock.

Methods, systems and computer program products provide protection domains for processes in shared address space. Multiple processes may share address space, for example, in a software isolated process running on top of a library operating system (OS). A protection domain (PD), such as a Protection Key (PKEY), may be assigned to a process to protect its allocated address spaces from access by other processes. PDs may be acquired from a host OS. A library OS may manage PDs to protect processes and/or data. A PD may be freed and reassigned to a different process or may be concurrently assigned to multiple processes, for example, when the number of processes exceeds the number of protection domains. Threads spawned by a process may inherit protection provided by a PD assigned to the process. Process PDs may be disassociated with address spaces as they are deallocated for a process or its threads.

Performing atomic store-and-invalidate operations in processor-based devices is disclosed. In this regard, a processing element (PE) of one or more PEs of a processor-based device includes a store-and-invalidate logic circuit used by a memory access stage of an execution pipeline of the PE to perform an atomic store-and-invalidate operation. Upon receiving an indication to perform a store-and-invalidate operation (e.g., in response to a store-and-invalidate instruction execution) comprising a store address and store data, the memory access stage uses the store-and-invalidate logic circuit to write the store data to a memory location indicated by the store address, and to invalidate an instruction cache line corresponding to the store address in an instruction cache of the PE. The operations for storing data and invalidating instruction cache lines are performed as one atomic store-and-invalidate operation, such that the store-and-invalidate operation is considered successful only if both the store and invalidate operations are successful.

A data processing apparatus is provided, which includes a cache to store operations produced by decoding instructions fetched from memory. The cache is indexed by virtual addresses of the instructions in the memory. Receiving circuitry receives an incoming invalidation request that references a physical address in the memory. Invalidation circuitry invalidates entries in the cache where the virtual address corresponds with the physical address. Coherency is thereby achieved when using a cache that is indexed using virtual addresses.

A microprocessor includes: a first memory bus; a second memory bus; a fetch part configured to fetch an instruction from a first memory connected to the first memory bus; a bus controller configured to control the second memory bus; a determination part configured to determine whether or not an address output from the bus controller is in an area of the first memory; and a first logic circuit part configured to use an output of the determination part to set an access destination of the first memory as the bus controller when the address output from the bus controller is in the area of the first memory.

In an embodiment, a processor includes hardware circuitry and/or supports instructions which may be used to detect that a return address or jump address has been modified since it was written to memory. In response to detecting the modification, the processor may be configured to signal an exception or otherwise initiate error handling to prevent execution at the modified address. In an embodiment, the processor may perform a cryptographic sign operation on the return address/jump address before writing the signed return address/jump address to memory and the signature may be verified before the address is used as a return target or jump target. Security of the system may be improved by foiling ROP/JOP attacks.

A method comprises: compiling the code segment with a compiler; and determining, based on an intermediate result of the compiling, a resource associated with a dedicated processing unit and for executing the code segment. As such, the resource required for executing a code segment may be determined quickly without actually executing the code segment and allocating or releasing the resource, which helps subsequent resource allocation and further brings about a better user experience.

Systems and methods for configuring a reduced instruction set computer processor architecture to execute fully homomorphic encryption (FHE) logic gates as a streaming topology. The method includes parsing sequential FHE logic gate code, transforming the FHE logic gate code into a set of code modules that each have in input and an output that is a function of the input and which do not pass control to other functions, creating a node wrapper around each code module, configuring at least one of the primary processing cores to implement the logic element equivalents of each element in a manner which operates in a streaming mode wherein data streams out of corresponding arithmetic logic units into the main memory and other ones of the plurality arithmetic logic units.

Methods and apparatuses relating to preventing the execution of a modified instruction. In one embodiment, an apparatus includes a hardware binary translator to translate an instruction to a translated instruction, and a consistency hardware manager to prevent execution of the translated instruction by a hardware processor on detection of a modification to a virtual to physical address mapping of the instruction after the translation.