RVFI INSTR IF - Heed clicptr in is_instr_bus_valid
#2565
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Signed-off-by: Robin Pedersen <[email protected]>
silabs-robin
commented
Dec 11, 2024
| @@ -275,6 +276,10 @@ interface uvma_rvfi_instr_if_t | |||
|
|
|||
| asm_t instr_asm; | |||
|
|
|||
| wire is_exception_cause_instr_acc_fault = (rvfi_trap.exception_cause == EXC_CAUSE_INSTR_ACC_FAULT); | |||
| wire is_exception_cause_integrity_fault = (rvfi_trap.exception_cause == EXC_CAUSE_INSTR_INTEGRITY_FAULT); | |||
| wire is_exception_cause_bus_fault = (rvfi_trap.exception_cause == EXC_CAUSE_INSTR_BUS_FAULT); | |||
There was a problem hiding this comment.
Note: Having one single token (instead of 8) makes it easier to reason about the boolean expression (for is_instr_bus_valid) that combines all of these 3 boolean expressions.
There was a problem hiding this comment.
Good idea. Maybe put in a comment to that effect.
| !is_exception_cause_integrity_fault && | ||
| !is_exception_cause_instr_acc_fault | ||
| ) || | ||
| rvfi_trap.clicptr |
There was a problem hiding this comment.
Note: This is the primary change. rvfi_trap.clicptr can now "make the instr valid after all".
MikeOpenHWGroup
added
enhancement
|
Nice @silabs-robin. I'll hold off on the Approval until you've removed the "draft" lablel. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR amends
uvma_rvfi_instr_if, making sureis_instr_bus_validconsidersrvfi_trap.clicptr.Relevant
clicptrspec:https://docs.openhwgroup.org/projects/cv32e40x-user-manual/en/latest/rvfi.html#compatibility
"rvfi_trap.clicptr is set for CLIC pointers. CLIC pointers are only reported on RVFI when they get an exception during fetch."
Test status:
ci_check- Passed ✅Background:
Here is the assert that failed before: a_mintstatus_mil_decrease_intended.
It required an
mretin a certain situation, but the RVFI instr if claimed that there was nomretbecause of an "instruction access fault". (The fault was on the pointer fetch, but the mret itself was fine.)