Abstract: Detailed herein are examples of instructions and their hardware support for floating-point comparison that makes use of the distinction between signed integer comparison and unsigned integer comparison to make an analogous distinction between floating-point relationships including unordered and those that do not. These instructions may reduce the number of instructions required to compare and conditionally execute operations in a program, including instructions to load values and instructions to explicitly test for the unordered condition.

Abstract: Techniques for flexible return and event delivery are described. In particular, in some examples, event delivery causes a stack switch if the event stack level is greater than the current stack level wherein the new stack level is always the greater of the current stack level and the event stack level.

Abstract: Embodiments of an invention for protecting supervisor mode information are disclosed. In one embodiment, an apparatus includes a storage location, instruction hardware, execution hardware, and control logic. The storage location is to store an indicator to enable supervisor mode information protection. The instruction hardware is to receive an instruction to access supervisor mode information. The execution hardware is to execute the instruction. The control logic is to prevent execution of the instruction if supervisor mode information protection is enabled and a current privilege level is less privileged than a supervisor mode.

Abstract: An apparatus and method for efficiently managing shadow stacks. For example, one embodiment of a processor comprises: a plurality of registers to store a plurality of shadow stack pointers (SSPs); event processing circuitry to select a first SSP of the plurality of SSPs from a first register of the plurality of registers responsive to receipt of a first event associated with a first event priority level, the first SSP usable to identify a top of a first shadow stack; verification and utilization checking circuitry to determine whether the first SSP has been previously verified, wherein if the first SSP has not been previously verified then initiating a set of atomic operations to verify the first SSP and confirm that the first SSP is not in use, the set of atomic operations using a locking operation to lock data until the set of atomic operations are complete.

Abstract: In one embodiment, a processor includes: a front end circuit to fetch and decode a read list instruction, the read list instruction to cause storage to a memory of a software-provided list of processor state information; and an execution circuit coupled to the front end circuit. The execution circuit, in response to the decoded read list instruction, is to read the processor state information stored in the processor and store each datum of the processor state information into an entry of a data table in the memory. Other embodiments are described and claimed.

Abstract: Techniques for flexible return and event delivery are described. As an example, an exemplary apparatus includes decoder circuitry to decode a single instruction, the single instruction to include a field for an opcode; and execution circuitry to execute the decoded single instruction according to the opcode to cause a return from an event handler while staying in a most privileged level and establish a return context that was in effect before event delivery.

Abstract: An apparatus and method for efficiently managing shadow stacks. For example, one embodiment of a processor comprises: a plurality of registers to store a plurality of shadow stack pointers (SSPs); event processing circuitry to select a first SSP of the plurality of SSPs from a first register of the plurality of registers responsive to receipt of a first event associated with a first event priority level, the first SSP usable to identify a top of a first shadow stack; verification and utilization checking circuitry to determine whether the first SSP has been previously verified, wherein if the first SSP has not been previously verified then initiating a set of atomic operations to verify the first SSP and confirm that the first SSP is not in use, the set of atomic operations using a locking operation to lock data until the set of atomic operations are complete.

Abstract: An apparatus and method for efficiently managing shadow stacks.

Abstract: A processor of an aspect includes a decode unit to decode a user-level suspend thread instruction that is to indicate a first alternate state. The processor also includes an execution unit coupled with the decode unit. The execution unit is to perform the instruction at a user privilege level. The execution unit in response to the instruction, is to: (a) suspend execution of a user-level thread, from which the instruction is to have been received; (b) transition a logical processor, on which the user-level thread was to have been running, to the indicated first alternate state; and (c) resume the execution of the user-level thread, when the logical processor is in the indicated first alternate state, with a latency that is to be less than half a latency that execution of a thread can be resumed when the logical processor is in a halt processor power state.

Abstract: An apparatus and method for efficiently managing shadow stacks.

Abstract: Embodiments of an invention for protecting supervisor mode information are disclosed. In one embodiment, an apparatus includes a storage location, instruction hardware, execution hardware, and control logic. The storage location is to store an indicator to enable supervisor mode information protection. The instruction hardware is to receive an instruction to access supervisor mode information. The execution hardware is to execute the instruction. The control logic is to prevent execution of the instruction if supervisor mode information protection is enabled and a current privilege level is less privileged than a supervisor mode.

Abstract: A processor of an aspect includes a decode unit to decode a user-level suspend thread instruction that is to indicate a first alternate state. The processor also includes an execution unit coupled with the decode unit. The execution unit is to perform the instruction at a user privilege level. The execution unit in response to the instruction, is to: (a) suspend execution of a user-level thread, from which the instruction is to have been received; (b) transition a logical processor, on which the user-level thread was to have been running, to the indicated first alternate state; and (c) resume the execution of the user-level thread, when the logical processor is in the indicated first alternate state, with a latency that is to be less than half a latency that execution of a thread can be resumed when the logical processor is in a halt processor power state.

Abstract: Embodiments of an invention for protecting supervisor mode information are disclosed. In one embodiment, an apparatus includes a storage location, instruction hardware, execution hardware, and control logic. The storage location is to store an indicator to enable supervisor mode information protection. The instruction hardware is to receive an instruction to access supervisor mode information. The execution hardware is to execute the instruction. The control logic is to prevent execution of the instruction if supervisor mode information protection is enabled and a current privilege level is less privileged than a supervisor mode.

Abstract: Embodiments of an invention for protecting supervisor mode information are disclosed. In one embodiment, an apparatus includes a storage location, instruction hardware, execution hardware, and control logic. The storage location is to store an indicator to enable supervisor mode information protection. The instruction hardware is to receive an instruction to access supervisor mode information. The execution hardware is to execute the instruction. The control logic is to prevent execution of the instruction if supervisor mode information protection is enabled and a current privilege level is less privileged than a supervisor mode.

Abstract: Embodiments of an invention for protecting supervisor mode information are disclosed. In one embodiment, an apparatus includes a storage location, instruction hardware, execution hardware, and control logic. The storage location is to store an indicator to enable supervisor mode information protection. The instruction hardware is to receive an instruction to access supervisor mode information. The execution hardware is to execute the instruction. The control logic is to prevent execution of the instruction if supervisor mode information protection is enabled and a current privilege level is less privileged than a supervisor mode.

Abstract: Embodiments of an invention for protecting supervisor mode information are disclosed. In one embodiment, an apparatus includes a storage location, instruction hardware, execution hardware, and control logic. The storage location is to store an indicator to enable supervisor mode information protection. The instruction hardware is to receive an instruction to access supervisor mode information. The execution hardware is to execute the instruction. The control logic is to prevent execution of the instruction if supervisor mode information protection is enabled and a current privilege level is less privileged than a supervisor mode.

Abstract: Embodiments of an invention for protecting supervisor mode information are disclosed. In one embodiment, an apparatus includes a storage location, instruction hardware, execution hardware, and control logic. The storage location is to store an indicator to enable supervisor mode information protection. The instruction hardware is to receive an instruction to access supervisor mode information. The execution hardware is to execute the instruction. The control logic is to prevent execution of the instruction if supervisor mode information protection is enabled and a current privilege level is less privileged than a supervisor mode.

Abstract: A processor of an aspect includes a decode unit to decode an exception handler return instruction. The processor also includes an exception handler return execution unit coupled with the decode unit. The exception handler return execution unit, responsive to the exception handler return instruction, is to not configure the processor to enable delivery of a subsequently received nonmaskable interrupt (NMI) to an NMI handler if an exception, which corresponds to the exception handler return instruction, was taken within the NMI handler. The exception handler return execution unit, responsive to the exception handler return instruction, is to configure the processor to enable the delivery of the subsequently received NMI to the NMI handler if the exception was not taken within the NMI handler. Other processors, methods, systems, and instructions are disclosed.

Abstract: A processor of an aspect includes a decode unit to decode a user-level suspend thread instruction that is to indicate a first alternate state. The processor also includes an execution unit coupled with the decode unit. The execution unit is to perform the instruction at a user privilege level. The execution unit in response to the instruction, is to: (a) suspend execution of a user-level thread, from which the instruction is to have been received; (b) transition a logical processor, on which the user-level thread was to have been running, to the indicated first alternate state; and (c) resume the execution of the user-level thread, when the logical processor is in the indicated first alternate state, with a latency that is to be less than half a latency that execution of a thread can be resumed when the logical processor is in a halt processor power state.

Abstract: Instructions and logic provide memory key protection functionality. Embodiments include a processor having a register to store a memory protection field. A decoder decodes an instruction having an addressing form field for a memory operand to specify one or more memory addresses, and a memory protection key. One or more execution units, responsive to the memory protection field having a first value and to the addressing form field of the decoded instruction having a second value, enforce memory protection according to said first value of the memory protection field, using the specified memory protection key, for accessing the one or more memory addresses, and fault if a portion of the memory protection key specified by the decoded instruction does not match a stored key value associated with the one or more memory addresses.