Abstract: Embodiments described herein enable the interoperability between processes configured for pointer authentication and processes that are not configured for pointer authentication. Enabling the interoperability between such processes enables essential libraries, such as system libraries, to be compiled with pointer authentication, while enabling those libraries to still be used by processes that have not yet been compiled or configured to use pointer authentication.

Abstract: In an embodiment, processors may have associated special purpose registers (SPRs) such as model specific registers (MSRs), used to communicate IPIs between the processors. In an embodiment, several types of IPIs may be defined, such as one or more of an immediate type, a deferred type, a retract type, and/or a non-waking type. The immediate IPI may be delivered and may cause the target processor to interrupt in response to receipt of the IPI. The deferred IPI may be delivered within a defined time limit, and not necessarily on receipt by the target processor. The retract IPI may cause a previously transmitted IPI to be cancelled (if it has not already caused the target processor to interrupt). A non-waking IPI may not cause the target processor to wake if it is asleep, but may be delivered when the target processor is awakened for another reason.

Abstract: In one embodiment, a system includes a non-volatile memory that may serve as both the main memory system and the backing store (or persistent storage). In some embodiments, the non-volatile memory is divided into a main memory portion and a persistent portion. Data in the main memory operation may be encrypted using one or more first keys, and data in the persistent portion may be encrypted using one or more second keys, in an embodiment. The volatile behavior of main memory may be implemented by discarding the one or more first keys in a power down event or other event that indicates a loss of main memory data, while the one or more second keys may be retained. In one embodiment, the physical address space of the non-volatile memory may be a mapping from a second physical address space that is used within the system.

Abstract: Systems, apparatuses, and methods for modifying access permissions in a processor. A processor may include one or more permissions registers for managing access permissions. A first permissions register may be utilized to override access permissions embedded in the page table data. A plurality of bits from the page table data may be utilized as an index into the first permissions register for the current privilege level. An attribute field may be retrieved from the first permissions register to determine the access permissions for a given memory request. A second permissions register may also be utilized to set the upper and lower boundary of a region in physical memory where the kernel is allowed to execute. A lock register may prevent any changes from being made to the second permissions register after the second permissions register has been initially programmed.

Abstract: Techniques are disclosed relating to register caching techniques for thread switches. In one embodiment, an apparatus includes a register file and caching circuitry. In this embodiment, the register file includes a plurality of registers and the caching circuitry is configured to store information that indicates threads that correspond to data stored in respective ones of the plurality of registers. In this embodiment, the apparatus is configured to store, at a point in time at which a first register of the plurality of registers includes first valid data corresponding to a first thread, second valid data corresponding to a second thread in a second register of the plurality of registers. In some embodiments, the disclosed techniques may reduce context switch latency, reduce pressure on a data cache, and/or allow smaller slices of thread execution, for example.

Abstract: Techniques are disclosed relating to register caching techniques for thread switches. In one embodiment, an apparatus includes a register file and caching circuitry. In this embodiment, the register file includes a plurality of registers and the caching circuitry is configured to store information that indicates threads that correspond to data stored in respective ones of the plurality of registers. In this embodiment, the apparatus is configured to store, at a point in time at which a first register of the plurality of registers includes first valid data corresponding to a first thread, second valid data corresponding to a second thread in a second register of the plurality of registers. In some embodiments, the disclosed techniques may reduce context switch latency, reduce pressure on a data cache, and/or allow smaller slices of thread execution, for example.

Abstract: In an embodiment, a timer unit may be provided that may be programmed to a selected time interval, or wakeup interval. A processor may execute a wait for event instruction, and enter a low power state for the thread that includes the instruction. The timer unit may signal a timer event at the expiration of the wakeup interval, and the processor may exit the low power state in response to the timer event. The thread may continue executing with the instruction following the wait for event instruction. In an embodiment, the processor/timer unit may be used to implement a power-managed lock acquisition mechanism, in which the processor is awakened a number of times to check the lock and execute the wait for event instruction if the lock is not free, after which the thread may block until the lock is free.

Abstract: In an embodiment, a timer unit may be provided that may be programmed to a selected time interval, or wakeup interval. A processor may execute a wait for event instruction, and enter a low power state for the thread that includes the instruction. The timer unit may signal a timer event at the expiration of the wakeup interval, and the processor may exit the low power state in response to the timer event. The thread may continue executing with the instruction following the wait for event instruction. In an embodiment, the processor/timer unit may be used to implement a power-managed lock acquisition mechanism, in which the processor is awakened a number of times to check the lock and execute the wait for event instruction if the lock is not free, after which the thread may block until the lock is free.

Abstract: In an embodiment, a timer unit may be provided that may be programmed to a selected time interval, or wakeup interval. A processor may execute a wait for event instruction, and enter a low power state for the thread that includes the instruction. The timer unit may signal a timer event at the expiration of the wakeup interval, and the processor may exit the low power state in response to the timer event. The thread may continue executing with the instruction following the wait for event instruction. In an embodiment, the processor/timer unit may be used to implement a power-managed lock acquisition mechanism, in which the processor is awakened a number of times to check the lock and execute the wait for event instruction if the lock is not free, after which the thread may block until the lock is free.

Abstract: In an embodiment, a timer unit may be provided that may be programmed to a selected time interval, or wakeup interval. A processor may execute a wait for event instruction, and enter a low power state for the thread that includes the instruction. The timer unit may signal a timer event at the expiration of the wakeup interval, and the processor may exit the low power state in response to the timer event. The thread may continue executing with the instruction following the wait for event instruction. In an embodiment, the processor/timer unit may be used to implement a power-managed lock acquisition mechanism, in which the processor is awakened a number of times to check the lock and execute the wait for event instruction if the lock is not free, after which the thread may block until the lock is free.

Abstract: In an embodiment, a timer unit may be provided that may be programmed to a selected time interval, or wakeup interval. A processor may execute a wait for event instruction, and enter a low power state for the thread that includes the instruction. The timer unit may signal a timer event at the expiration of the wakeup interval, and the processor may exit the low power state in response to the timer event. The thread may continue executing with the instruction following the wait for event instruction. In an embodiment, the processor/timer unit may be used to implement a power-managed lock acquisition mechanism, in which the processor is awakened a number of times to check the lock and execute the wait for event instruction if the lock is not free, after which the thread may block until the lock is free.