| commit | 15daa83ee2abb7abecc0140bcbe043a013111dfd | [log] [tgz] |
|---|---|---|
| author | Timothy Trippel <ttrippel@google.com> | Tue Nov 30 00:38:11 2021 +0000 |
| committer | Michael Munday <mike.munday@lowrisc.org> | Thu Dec 02 09:57:32 2021 +0000 |
| tree | c9164914af2e37d2d7cfe79bee97a3c467c27a48 | |
| parent | 9aeaac797a34043b2a04424f3128d3dc02e75c4c [diff] |
[sw/ottf] Fix bugs saving/restoring stack pointer in ISRs. The OTTF was optimized in #9158 to allow running bare-metal tests (in place of running each test as a FreeRTOS "task") if the test did NOT require spawning (additional) concurrenct tasks. This introduced a bug in the ISR assembly that saves/restores the current execution context to the stack upon entry/exit from the ISR. For tests run as a FreeRTOS task, i.e., tests that set the `enable_concurrency` flag in the test configuration struct (see `test_config_t` in `sw/device/lib/testing/test_framework/ottf.h`), the current stack pointer must be saved/restored from the current Task Control Block (TCB) because each FreeRTOS task maintains a separate stack and a context switch could happen in an exception handler (task yield) or ISR (preemption). However, for bare-metal tests, the current TCB pointer (which is initialized and maintained by FreeRTOS) is NULL. Therefore attempting to dereference said pointer results in a store access fault. This commit fixes this bug by checking the test mode (bare-metal vs. concurrency) in the ISR entry/exit assembly to store/load the proper execution context state. Signed-off-by: Timothy Trippel <ttrippel@google.com>
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.
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