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Specification
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Resolution: Unresolved
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Medium
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Not Required
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Double Trap
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Yes
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ISA
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Ssdbltrp, Smdbltrp
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Freeze Approved
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In Progress
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10
A double trap typically arises during a sensitive phase in trap handling operations - when an exception or interrupt occurs while the trap handler, the component responsible for managing these events, is in a non-reentrant state. This non-reentrancy usually occurs in the early phase of trap handling, where the trap handler hasn't yet preserved the necessary state to handle and resume from the trap. The occurrence of a second trap during this phase can lead to an overwrite of this critical state information, resulting in the loss of data needed to recover from the initial trap. Trap handlers are designed to neither enable interrupts nor cause exceptions during this phase of handling. However, managing Hardware-Error exceptions, which may occur unpredictably, presents a significant challenge in trap handler implementation due to the potential risk of a double trap condition triggered by such a Hardware-Error exception. The Double Trap Extensions tackles situations where conventional fault handling mechanisms fall short in dealing with double trap conditions.
- is governed by
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RVG-59 Privileged Spec (IC)
- Active