This esoteric bug manifests if a tag-read error occurs when a FENCE.I is
executed, even if the error was correctable. Subsequently, an attempt to
flush a dirty line may flush the wrong line's data.
Deallocation can change repl_way, which violates the assumption that it
remains constant throughout refill.
The workaround described in commit 3db066303b
still suffices, provided only the hart that owns the ITIM changes the ITIM
allocation.
This subsumes commit 3db066303b.
...instead of on the master side of the system bus.
People inheriting from HasTileMasterPort might need to add
`masterNode := tileBus.node` to their Tile child class.
- Put correctness responsibility on Frontend, not IBuf, for improved
separation of concerns. Frontend must detect case that the BTB
predicts a taken branch in the middle of an instruction.
- Pass BTB information down pipeline unconditionally, fixing case that
screws up the branch history when the BTB misses and the instruction
is misaligned.
- Remove jumpInFrontend option; it's now unconditional.
- Default to one-bit counters in the BHT. For tiny BHTs like these, it's
more resource efficient to have a larger index space than to have
hysteresis.
Fragmenter: add a third case for earlyAck (PutFulls only)
It seems quite common to have a device that is backed by ECC. When
performing a multibeat PutPartial, these devices can exhibit their
first error on the last beat (if it had an incomplete write mask
for that beat, which required read-write-modifying corrupted data).
Generally, these devices have ECC granularity <= the bus width. In
those cases, if you send a PutFull, the first beat carries the
error value for the whole burst. Consider:
If the PutFull was below the granularity, it was a single beat.
If the PutFull was multi-beat, it exceeds the granularity.
Therefore, an important variation on the earlyAck optimization is
the case where only PutFulls receive an earlyAck.
* CSR provides a decode port to check for an illegal instruction.
* This commit now allows for multiple instructions in decode to get this
illegal instruction information.
* This commit leverages the existing decodeWidth parameter. This will
potentially over-provision the number of decode ports needed for
RVC-enabled cores.
Closes#1068
We had planned for a while to add an 'Overwrite' message which obtains
permissions without requiring retrieval of data. This is useful whenever
a master knows it will completely replace the contents of a cache block.
Instead of calling it Overwrite, we decided to split the Acquire type.
If you AcquirePerm, you MUST Release and ProbeAck with Data.
