摘要:
A method and apparatus for the prevention of unwanted access to secure areas of memory during the POR or boot sequence of a CPU. Via control within the CPU, commands that are sent to and received by the CPU prior to the finish of the POR sequence can be denied I/O address translation, thus protecting memory during the POR sequence. Furthermore, an error response can be generated in the CPU and sent back to the I/O device which issued the command.
摘要:
Embodiments of the present invention provide methods and systems for maintaining command order while processing commands in a command queue. Commands may be queued in an input command queue at the CPU. During address translation for a command, subsequent commands may be processed to increase efficiency. Processed commands may be placed in an output queue and sent to the CPU in order. If address translation entries for a command are not found, the translation entries may be retrieved from memory. Address translations for subsequent commands depending from the command getting the miss may be preserved until the address translation entry is retrieved from memory. Therefore, retranslation of addresses for subsequent commands is avoided.
摘要:
Embodiments of the present invention provide methods and systems for maintaining command order while processing commands in a command queue while handling translation cache misses. Commands may be queued in an input command queue at the CPU. During address translation for a command, subsequent commands may be processed to increase efficiency. Processed commands may be placed in an output queue and sent to the CPU in order. During address translation, if a translation cache miss occurs the relevant translation cache entries may be retrieved from memory. After the relevant entries are retrieved a notification may be sent requesting reissue of the command getting the translation cache miss.
摘要:
Embodiments of the present invention provide methods and systems for maintaining command order while processing commands in a command queue while handling multiple translation cache misses. Commands may be queued in an input command queue at the CPU. During address translation for a command, subsequent commands may be processed to increase efficiency. Processed commands may be placed in an output queue and sent to the CPU in order. During address translation, if a translation cache miss occurs while an outstanding miss is being handled, the pipeline may be stalled and the command causing the second miss and all subsequent commands may be processed again after the first miss is handled.
摘要:
The present invention provides an improved way to calculate a replacement way within a processor cache that is effective with different combinations of hardware address translation cache miss handling, software address translation cache miss handling, and hint lock bits. For some embodiments, LRU bits used to select an entry for replacement are updated only if software address translation cache miss handling is disabled. Further, for some embodiments, LRU bits may be modified to change the way a binary tree structure is traversed to avoid selecting a hint locked entry for replacement
摘要:
A method and apparatus for allowing multiple devices access to an address translation cache while cache maintenance operations are occurring at the same time. By interleaving the commands requiring address translation with maintenance operations that may normally take many cycles, address translation requests may have faster access to the address translation cache than if maintenance operations were allowed to stall commands requiring address translations until the maintenance operation was completed.
摘要:
Embodiments of the present invention generally provide an improved technique to handle I/O address translation cache misses caused by I/O commands within a CPU. For some embodiments, CPU hardware may buffer I/O commands that cause an I/O address translation cache miss in a command queue until the I/O address translation cache is updated with the necessary information. When the I/O address translation cache has been updated, the CPU may reissue the I/O command from the command queue, translate the address of the I/O command at a convenient time, and execute the command as if a cache miss did not occur. This way the I/O device does not need to handle an error response from the CPU, the I/O command is handled by the CPU, and the I/O command is not discarded.
摘要:
In a first aspect, a first method is provided. The first method includes the steps of (1) providing a cache having a plurality of cache entries, each entry adapted to store data, wherein the cache is adapted to be accessed by hardware and software in a first operational mode; (2) determining an absence of desired data in one of the plurality of cache entries; (3) determining a status based on a current operational mode and a value of hint-lock bits associated with the plurality of cache entries; and (4) determining availability of at least one of the cache entries based on the status, wherein availability of a cache entry indicates that data stored in the cache entry can be replaced. Numerous other aspects are provided.
摘要:
In a first aspect, a first method is provided for removing entries from an address cache. The first method includes the steps of (1) writing data to a register; and (2) removing a plurality of address cache entries from the address cache based on the data written to the register. Numerous other aspects are provided.
摘要:
Methods and apparatus for tracking dependencies of commands to be executed by a command processor are provided. By determining the dependency of incoming commands against all commands awaiting execution, dependency information can be stored in a dependency scoreboard. Such a dependency scoreboard may be used to determine if a command is ready to be issued by the command processor. The dependency scoreboard can also be updated with information relating to the issuance of commands, for example, as commands complete.