The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 13, 2008
Filed:
Mar. 25, 2004
Van Hoa Lee, Cedar Park, TX (US);
Van Hoa Lee, Cedar Park, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method, system, and computer instructions for providing valid translation entries in the TCE table for all supported DMA addresses to prevent the occurrence of system errors due to prefetching. The mechanism of the present invention reserves a page in system memory. This reserved page is made unavailable to the operating system and may not be utilized by any software in the system. The reserved page is also written with all bytes set to 0xFF. The system firmware then selects a region in system memory for the TCE table. The TCE table is initialized, with all entries within the TCE table initialized to be valid as well as contain the corresponding address of the reserved page. In this manner, all supported DMA page addresses will have valid TCE entries which translate the DMA addresses into the reserved page memory. Thus, prefetched DMA addresses will not encounter invalid DMA address translation, and crash the system.