Abstract: A processor, including: a core; system test circuitry, the system test circuitry to be locked during operational processor operation; reset circuitry including a kick-off test (KOT) input, the reset circuitry to detect a reset with the KOT input asserted, and to initiate an in-field system test (IFST) mode; a test interface controller to receive in IFST mode an encrypted test packet having a signature, verify the signature of the test packet, and decrypt the test packet; and IFST control circuitry to cause the system test circuitry to perform an IFST test according to the decrypted test packet and to log or report results.

Abstract: A processor, including: a core; system test circuitry, the system test circuitry configured to be locked except during an in-field system test (IFST) mode; IFST control circuitry; and a test interface controller, including: a data interface to receive a test packet; a parser to parse the test packet into a key, a signature, and a stored hash-of-hashes; a decryption circuit to decrypt the signature according to the key and to generate a computed hash-of-hashes; a hash circuit to verify the stored hash-of-hashes against the computed hash-of-hashes; and an IFST interface, wherein the test interface controller is to signal the IFST control circuitry to place the system test circuitry in IFST mode.

Abstract: A processor, including: a core; system test circuitry, the system test circuitry configured to be locked except during an in-field system test (IFST) mode; IFST control circuitry; and a test interface controller, including: a data interface to receive a test packet; a parser to parse the test packet into a key, a signature, and a stored hash-of-hashes; a decryption circuit to decrypt the signature according to the key and to generate a computed hash-of-hashes; a hash circuit to verify the stored hash-of-hashes against the computed hash-of-hashes; and an IFST interface, wherein the test interface controller is to signal the IFST control circuitry to place the system test circuitry in IFST mode.

Abstract: A processor, including: a core; system test circuitry, the system test circuitry to be locked during operational processor operation; reset circuitry including a kick-off test (KOT) input, the reset circuitry to detect a reset with the KOT input asserted, and to initiate an in-field system test (IFST) mode; a test interface controller to receive in IFST mode an encrypted test packet having a signature, verify the signature of the test packet, and decrypt the test packet; and IFST control circuitry to cause the system test circuitry to perform an IFST test according to the decrypted test packet and to log or report results.

Abstract: Embodiments of an invention for consecutive bit error detection and correction are disclosed. In one embodiment, an apparatus includes a storage structure, a second storage structure, a parity checker, an error correction code (ECC) checker, and an error corrector. The first storage structure is to store a plurality of data values, a plurality of parity values, and a plurality of ECC values, each parity value corresponding to one of the plurality of data values, a first bit of each parity value corresponding to a first of a plurality of portions of a corresponding data value, wherein the first of the plurality of portions of the corresponding data value is interleaved with a second of the plurality of portions of the corresponding data value, wherein a second bit of each parity value corresponds to a second of the plurality of portions of the corresponding data value, each ECC value corresponding to one of the plurality of data values.

Abstract: Embodiments of an invention for consecutive bit error detection and correction are disclosed. In one embodiment, an apparatus includes a storage structure, a second storage structure, a parity checker, an error correction code (ECC) checker, and an error corrector. The first storage structure is to store a plurality of data values, a plurality of parity values, and a plurality of ECC values, each parity value corresponding to one of the plurality of data values, a first bit of each parity value corresponding to a first of a plurality of portions of a corresponding data value, wherein the first of the plurality of portions of the corresponding data value is interleaved with a second of the plurality of portions of the corresponding data value, wherein a second bit of each parity value corresponds to a second of the plurality of portions of the corresponding data value, each ECC value corresponding to one of the plurality of data values.

Abstract: An error detection unit including one or more register files that store at least one operand and at least one operand residue, an operand multiplexor operable to receive the operand, a residue multiplexor operable to receive the operand residue, a source operand residue generator operable to generate at least one generated residue from the operand, a first comparator that compares the operand residue to the generated residue, the result of the first comparator being sent to a reorder buffer, an execution unit that supplies the operand to a residue calculator and a result residue generator, wherein the residue calculator operable to determine an expected residue and the result residue generator operable to generate a result residue, and a second comparator that compares the expected residue with the result residue, the result of the second comparator being sent to the reorder buffer.

Abstract: An error detection unit including one or more register files that store at least one operand and at least one operand residue, an operand multiplexor operable to receive the operand, a residue multiplexor operable to receive the operand residue, a source operand residue generator operable to generate at least one generated residue from the operand, a first comparator that compares the operand residue to the generated residue, the result of the first comparator being sent to a reorder buffer, an execution unit that supplies the operand to a residue calculator and a result residue generator, wherein the residue calculator operable to determine an expected residue and the result residue generator operable to generate a result residue, and a second comparator that compares the expected residue with the result residue, the result of the second comparator being sent to the reorder buffer.

Abstract: Methods and apparatus to provide core sparing on multi-core platforms are described. In an embodiment, stored core state information of a target core (e.g., a core that has detected a fault condition (e.g., within its circuitry) or a request to offload operations from the target core (e.g., to enable run-time diagnostics without interfering with system software)) may be read by a spare core which is to operationally replace the target core. Other embodiments are also described.

Abstract: A method and apparatus for saving and restoring architectural states utilizing hardware is described. A first portion of an architectural state of a processing element, such as a core, is concurrently saved upon being updated. A remaining portion of the architectural state is saved to memory in response to a save state triggering event, which may include a hardware event or a software event. Once saved, the state is potentially transferred to another processing element, such as a second core. As a result, hardware, software, or combination thereof may transfer architectural states between multiple processing elements, such as threads or cores, of a processor utilizing hardware support.

Abstract: In some embodiments a system includes one or more processing nodes, a backplane, and one or more links to couple the one or more processing nodes to the backplane, wherein at least one of the one or more links is configurable as a standard Input/Output link and/or as a proprietary link. Other embodiments are described and claimed.

Abstract: An end-to-end residue-based protection scheme protects multiple units/blocks of a floating point execution pipeline without the complexity and cost of having multiple protection schemes for the execution pipeline. Protecting an execution pipeline that supports floating point operations includes factoring in component operations, such as normalization and rounding, into a residue generated for a result. In addition, residues of operands are distilled to extract their corresponding mantissa residues, thus allowing the floating point operations (e.g., multiplication, addition, etc.) to be applied to the mantissa residues.

Abstract: A method and apparatus for saving and restoring architectural states utilizing hardware is herein described. A first portion of an architectural state of a processing element, such as a core, is concurrently saved upon being updated. A remaining portion of the architectural state is saved to memory in response to a save state triggering event, which may include a hardware event or a software event. Once saved, the state is potentially transferred to another processing element, such as a second core. As a result, hardware, software, or combination thereof may transfer architectural states between multiple processing elements, such as threads or cores, of a processor utilizing hardware support.

Abstract: A processor that protects an execution pipeline includes a residue-based error detection infrastructure including a first logic for computing a first residue of a result of an executed instruction instance, and a second logic for computing a second residue of the result. The second logic applies arithmetic operations of the executed instruction instance to residues of operands of the instruction instance. The execution pipeline includes registers and one or more arithmetic execution units. A method of protecting an execution pipeline includes performing one or more operations of an instruction instance on residues of operands of the instruction instance, computing a first residue of a result of the operations on the operand residues, computing a second residue from a result of executing the instruction instance, and checking the first residue against the second residue to determine whether errors were introduced while the instruction instance was resident in the execution pipeline.

Abstract: Errors in a shift result can be detected with a residue-based mechanism, instead of with duplication of an entire shifter. The commutative property of residue computation over a bit string allows the residue of a value to be independent of the actual bit positions when the divisor is a Merrill number. Without a duplicated shifter, an operand that is the subject of a shift operation is formatted to become a multiple of k, where divisor=2k?1, and the divisor is used for computation of residues. The shift operation is translated to a single position shift or a zero position shift. The translated shift is applied to the formatted operand to generate a shift check value. Despite different values, the residues of the shift result and the shift check value will be the same as long as bit groups are consistent between the two. An error(s) is detected by comparing the residue of the shift check value with the residue of the shift result.

Abstract: A multi-stride prefetcher includes a recurring prefetch table that in turn includes a stream table and an index table. The stream table includes a valid field and a tag field. The stream table also includes a thread number field to help support multi-threaded processor cores. The tag field stores a tag from an address associated with a cache miss. The index table includes fields for storing information characterizing a state machine. The fields include a learning bit. The multi-stride prefetcher prefetches data into a cache for a plurality of streams of cache misses, each stream having a plurality of strides.

Abstract: A method for optimizing a register file hierarchy in a multithreaded processor. The method includes providing a register file hierarchy with a plurality of register file cells, associating the plurality of register file cells with respective threads when the processor is operating in a multithreaded mode and flattening the plurality of register file cells with a single thread when the processor is operating in a single threaded mode. The register file cells correspond to threads of the multithreaded processor.

Abstract: Methods and apparatus to provide core sparing on multi-core platforms are described. In an embodiment, stored core state information of a target core (e.g., a core that has detected a fault condition (e.g., within its circuitry) or a request to offload operations from the target core (e.g., to enable run-time diagnostics without interfering with system software)) may be read by a spare core which is to operationally replace the target core. Other embodiments are also described.

Abstract: Offloading data coherence operations from a primary processing unit(s) executing instantiated code responsible for data coherence in a shared-cache cluster to a data coherence offload engine reduces resource consumption and allows for efficient sharing of data in accordance with the data coherence protocol. Some of the data coherence operations, such as consulting and maintaining a directory, generating messages, and writing a data unit can be performed by a data coherence offload engine. The data coherence offload engine indicates availability of the data unit in the memory to the appropriate instantiated code. Hence, the instantiated code (the corresponding primary processing unit) is no longer burdened with some of the work load of data coherence operations. Migration of tasks from a primary processing unit(s) to data coherence offload engines allows for efficient retrieval and writing of a requested data unit.

Abstract: The present application describes a method and a processor for handling register dependency conflicts between lesser and greater width instructions, colloquially referred to as “evil twins.” If there is a register dependency between a greater width producer instruction and a lesser width consumer instruction, a greater width source register is substituted for the source register specified by the lesser width producer. If there is a register dependency between a lesser width producer instruction and a greater width producer instruction, the greater width consumer instruction is replaced by multiple helper instructions. One or more of the helper instructions merge lesser width registers aliased onto the source registers specified by the greater width consumer instruction, into temporary registers. Another helper instruction executes the greater width consumer instruction using the temporary registers instead of the original source registers.