Methods and indirect branch predictor logic units to predict the target addresses of indirect branch instructions. The method comprises storing in a table predicted target addresses for indirect branch instructions indexed by a combination of the indirect path history for previous indirect branch instructions and the taken/not-taken history for previous conditional branch instructions. When a new indirect branch instruction is received for prediction, the indirect path history and the taken/not-taken history are combined to generate an index for the indirect branch instruction. The generated index is then used to identify a predicted target address in the table. If the identified predicted target address is valid, then the target address of the indirect branch instruction is predicted to be the predicted target address.

Systems and methods for managing optimized branching in executable instructions are disclosed. In one implementation, a processing device may identify, in a sequence of executable instructions, a branching instruction associated with a safe static key, the branching instruction specifying a first target location. The processing device may determine whether a value of the safe static key is initialized. Responsive to determining that the value of the safe static key is initialized, the processing device may further replace the branching instruction with an unconditional branching instruction specifying the first target location. Responsive to determining that the value of the safe static key is uninitialized, the processing device may replace the branching instruction with a conditional branching instruction specifying the first target location.

A computer implemented method of translation of verification commands of an electronic design file of an electronic circuit defined by the electronic design file, comprising receiving, at a processor, the electronic design file defining a functional level electronic design of the electronic circuit, wherein said electronic circuit comprises at least two subsystems and said electronic circuit includes at least two configuration options for the at least two subsystems, receiving along with the electronic design file, at least one analog test harness model having at least one indirect branch contribution statement, translating said at least one indirect branch contribution statement into a plurality of direct branch contribution operators based at least in part upon said at least one analog test harness model and said electronic design file and generating a netlist for the electronic circuit based at least in part upon said translation of said at least one indirect branch contribution statement.

A system for detecting malware includes a processor to collect processor trace information corresponding to an application being executed by the processor (202). The processor can also detect an invalid indirect branch instruction from the processor trace information (204) and detect at least one malware instruction being executed by the application in response to analyzing modified memory values corresponding to the invalid indirect branch (206). Additionally, the processor can block the application from accessing or modifying memory (208).

The present disclosure is directed to systems and methods for mitigating or eliminating the effectiveness of a side-channel based attack, such as one or more classes of an attack commonly known as Spectre. Novel instruction prefixes, and in certain embodiments one or more corresponding instruction prefix parameters, may be provided to enforce a serialized order of execution for particular instructions without serializing an entire instruction flow, thereby improving performance and mitigation reliability over existing solutions. In addition, improved mitigation of such attacks is provided by randomizing both the execution branch history as well as the source address of each vulnerable indirect branch, thereby eliminating the conditions required for such attacks.

Instruction set architecture extensions to configure priority ordering of divergent target branch instructions on SIMT computing platforms to enable tools such as compilers (e.g., under influence of execution profilers) or human software developers to configure branch direction prioritization explicitly in code. Extensions for simple (two-way) branch instructions as well as multi-target (more than two branch target instructions) are disclosed.

A method for predicting a fetch address of a next instruction to be fetched includes selecting, at a processor, a first way identifier or a second way identifier as a way pointer based on an active fetch address and historical prediction data. A first predictor table includes a first entry having the first way identifier and a second predictor table includes a second entry having the second way identifier. The method also includes selecting a first or second fetch address as a predicted fetch address based on the way pointer. A target table includes a first way storing the first fetch address and a second way storing the second fetch address. The first way and the second way are associated with the active fetch address. The first fetch address is associated with the first way identifier and the second fetch address is associated with the second way identifier.

Technologies for indirect branch target security include a computing device having a processor to execute an indirect branch instruction. The processor may determine an indirect branch target of the indirect branch instruction, load a memory tag associated with the indirect branch target, and determine whether the memory tag is set. The processor may generate a security fault if the memory tag is not set. The processor may load an encrypted indirect branch target, decrypt the encrypted branch target using an activation record key stored in an activation key register, and perform a jump to the indirect branch target. The processor may generate a next activation record coordinate as a function of the activation record key and a return address of a call instruction and generate the next activation record key as a function of the next activation record coordinate. Other embodiments are described and claimed.

In one embodiment, a microprocessor, comprising: a branch prediction table comprising plural entries, wherein at least a portion of the plural entries corresponds to an indirect branch type; and an indirect valid table; wherein based on an indirect branch instruction fetch, an entry corresponding to an indirect branch instruction in the branch prediction table is configured as invalid based on clearing a corresponding entry in the indirect valid table.

A technique for operating a processor includes identifying a difficult branch instruction (branch) whose target address (target) has been mispredicted multiple times. Information about the branch (which includes a current target and a next target) is learned and stored in a data structure. In response to the branch executing subsequent to the storing, whether a branch target of the branch corresponds to the current target in the data structure is determined. In response to the branch target of the branch corresponding to the current target of the branch in the data structure, the next target of the branch that is associated with the current target of the branch in the data structure is determined. In response to detecting that a next instance of the branch has been fetched, the next target of the branch is utilized as the predicted target for execution of the next instance of the branch.