| commit | 6d7e5dd10741acda2fe7b8ab16cb48a4d4fe97fa | [log] [tgz] |
|---|---|---|
| author | Andreas Kurth <adk@lowrisc.org> | Tue Aug 30 11:14:50 2022 +0000 |
| committer | Greg Chadwick <mail@gregchadwick.co.uk> | Thu Sep 01 16:38:30 2022 +0100 |
| tree | cfa01eecf28640a72fdcfdf1aef5deb9d5fd8d32 | |
| parent | 125b7c54097e12c3af35fe6cf42d51457b5928b0 [diff] |
[otbn,rtl] Fix `BAD_DATA_ADDR` unknown on pop from empty call stack Prior to this commit, when a load or store used the call stack as address and the call stack was empty, that may or may not result in a `BAD_DATA_ADDR` error depending on the residual value in the empty call stack. However, a value popped from an empty stack is by definition undefined and can thus not be decided as bad data address. Furthermore, this was problematic in most RTL simulators, where an empty call stack that has never been pushed contains an unknown (X) value, so the `BAD_DATA_ADDR` error bit became unknown. This is described in more detail in #13641. These problems can be reproduced with the `bnlid-1.s` test program, which is run as part of the `otbn_multi_err` test. This commit fixes these problems by explicitly *not* setting the `BAD_DATA_ADDR` error bit when a load or store uses the call stack as address and the call stack is empty. It therefore fixes #13641. Signed-off-by: Andreas Kurth <adk@lowrisc.org>
OpenTitan is an open source silicon Root of Trust (RoT) project. OpenTitan will make the silicon RoT design and implementation more transparent, trustworthy, and secure for enterprises, platform providers, and chip manufacturers. OpenTitan is administered by lowRISC CIC as a collaborative project to produce high quality, open IP for instantiation as a full-featured product. See the OpenTitan site and OpenTitan docs for more information about the project.
This repository contains hardware, software and utilities written as part of the OpenTitan project. It is structured as monolithic repository, or “monorepo”, where all components live in one repository. It exists to enable collaboration across partners participating in the OpenTitan project.
The project contains comprehensive documentation of all IPs and tools. You can access it online at docs.opentitan.org.
Have a look at CONTRIBUTING and our documentation on project organization and processes for guidelines on how to contribute code to this repository.
Unless otherwise noted, everything in this repository is covered by the Apache License, Version 2.0 (see LICENSE for full text).