Intel SL6VU Specification Update - Page 43

Errata R and BLW transactions, or (2) all HITM snoop results without regard to the transaction type and snoop results' source. Workaround: 1. The central agent can issue a bus cycle that causes a cache line to be invalidated (Bus Read Invalidate Line (BRIL) or BWIL transaction) in response to a processor-generated BWIL (or BLW) transaction to insure complete invalidation of the associated cache line. If there are no intervening processor-originated transactions to that cache line, the central agent's invalidating snoop will get a clean snoop result. Or 2. Snoop filtering central agents can: a. Not use processor-originated BWIL or BLW transactions to update their snoop filter information, or b. Update the associated cache line state information to shared state on the originating bus (rather than invalid state) in reaction to a BWIL or BLW. Status: For the steppings affected, see the Summary Tables of Changes. AC65. Memory Control Register 2 (CR2) Can be Updated during a REP MOVS/STOS Instruction with Fast Strings Enabled Transaction Problem: Under limited circumstances while executing a REP MOVS/STOS string instruction, with fast strings enabled, it is possible for the value in CR2 to be changed as a result of an interim paging event, normally invisible to the user. Any higher priority architectural event that arrives and is handled while the interim paging event is occurring may see the modified value of CR2. Implication: The value in CR2 is correct at the time that an architectural page fault is signaled. Intel has not observed this erratum with any commercially available software. Workaround: None identified. Status: For the steppings affected, see the Summary Tables of Changes. AC66. Writing the Local Vector Table (LVT) when an Interrupt is Pending May Cause an Unexpected Interrupt Problem: If a local interrupt is pending when the LVT entry is written, an interrupt may be taken on the new interrupt vector even if the mask bit is set. Implication: An interrupt may immediately be generated with the new vector when a LVT entry is written, even if the new LVT entry has the mask bit set. If there is no Interrupt Service Routine (ISR) set up for that vector the system will GP fault. If the ISR does not do an End of Interrupt (EOI) the bit for the vector will be left set in the in-service register and mask all interrupts at the same or lower priority. Workaround: Any vector programmed into an LVT entry must have an ISR associated with it, even if that vector was programmed as masked. This ISR routine must do an EOI to clear any unexpected interrupts that may occur. The ISR associated with the spurious vector does not generate an EOI, therefore the spurious vector should not be used when writing the LVT. Status: For the steppings affected, see the Summary Tables of Changes Intel® Celeron® Processor in the 478-Pin Package Specification Update 43