| 摘要 |
What is provided is an enhanced dynamic address translation facility. In one embodiment, a virtual address to be translated is first obtained and an initial origin address of a translation table of the hierarchy of translation tables is obtained. Based on the obtained initial origin, a segment table entry is obtained. The segment table entry is configured to contain a format control and access validity fields. If the format control and access validity fields are enabled, the segment table entry further contains an access control field, a fetch protection field, and a segment-frame absolute address. Store operations are permitted only if the access control field matches a program access key provided by any one of a Program Status Word or an operand of a program instruction being emulated. Fetch operations are permitted if the program access key associated with the virtual address is equal to the segment access control field or the fetch protection field is not enabled. |
| 主权项 |
1. A computer program product for protecting data in a computer system having a hierarchy of translation tables used for translation of a virtual address into a translated address of a block of main storage, the computer program product comprising:
a computer readable storage medium readable by said computer system, said computer readable storage medium storing instructions for performing:
building the software routine to emulate execution of an instruction of a first computer architecture on a general purpose processor of an alternate computer architecture, the instruction configured to protect data, the software routine comprising a plurality of instructions, the software routine configured to cause the general purpose processor of the alternate computer architecture to performobtaining for translation a virtual address of a desired block of main storage;obtaining an initial origin address of a translation table in a hierarchy of translation tables, said hierarchy of translation tables comprising a segment table;based on said obtained initial origin address and said virtual address, obtaining a segment table entry from said segment table, said segment table entry configured to contain a format control field;based on an enhanced dynamic address translation (eDAT) facility being enabled, determining, by a processor, whether said format control field in said segment table entry is enabled; andbased on said format control field being enabled, performing:
determining whether an access validity field in said segment table entry is enabled, said segment table entry comprising said access validity field, a segment access control field, a segment fetch protection field and a segment-frame absolute address of a large block of main storage, said large block of main storage comprising said desired block of main storage; andbased on said access validity field being enabled, performing:
permitting stores to said desired block of storage, wherein the stores are associated with the virtual address, said stores permitted in response to said segment access control field matching a program access key provided by any one of a Program Status Word or an operand of a program instruction being executed, wherein the stores are associated with the virtual address; andnot permitting stores to said desired block of main storage based on said segment access control filed not matching said program access key, wherein the stores are associated with the virtual address. |
