riscv/rocket-chip
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61 Commits

Author SHA1 Message Date
Henry Cook
efe7165b54 tile: BaseTile refactor, pt 2 
* 2 layer cake
* no more bundle traits, only call to IO
 2018-01-02 15:37:31 -08:00
Henry Cook
1cd018546c tile: BaseTile refactor, pt 1 
* Make dts generation reusable across tile subclasses
* First attempt to standardize tile IO nodes and connect methods
* hartid => hartId when talking about scala Ints
 2017-12-26 11:04:15 -08:00
Andrew Waterman
676110bc1f Add cover for a1ebe6da4d 2017-12-07 21:03:42 -08:00
Andrew Waterman
a1ebe6da4d Prevent frontend deadlock fetching from uncacheable memory 
After detecting a corrupted BTB, don't speculatively update it until
the next non-speculative fetch.  This prevents the frontend from replaying
forever.
 2017-12-07 18:56:06 -08:00
Andrew Waterman
d0c6cbba6b Improve frontend branch prediction 
- 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.
 2017-11-09 00:00:56 -08:00
Andrew Waterman
7bcf28c585 Define fetchBytes in HasCoreParams, not Frontend 
It is more generally useful.
 2017-10-03 17:34:18 -07:00
Wesley W. Terpstra
60614055e3 diplomacy: eliminate some wasted IdentityNodes using cross-module refs 2017-09-25 12:06:27 -07:00
Wesley W. Terpstra
b9a2e4c243 diplomacy: API beautification 2017-09-22 15:01:42 -07:00
Wesley W. Terpstra
9217baf9d4 diplomacy: change API to auto-create node bundles => cross-module refs 2017-09-22 15:01:39 -07:00
Andrew Waterman
034ea722f4 Report I$ errors 2017-09-20 00:05:07 -07:00
Henry Cook
9c0bfbd500 tile: remove global Field ResetVectorBits 
Reset vector width is determined by systemBus.busView.
Also move some defs from HasCoreParameters to HasTileParameters.
 2017-09-08 14:50:59 -07:00
Wesley W. Terpstra
1365c5f90c diplomacy: implement DisableMonitors scope 2017-09-07 16:03:35 -07:00
Andrew Waterman
74d309c18e Make I vs. D a static property of TLB, not an input pin 
The microarchitecture doesn't really support unified TLBs, so don't fake it.
 2017-08-08 11:54:47 -07:00
Andrew Waterman
658e36f98b Reduce fanout on frontend io.cpu.req.valid signal 2017-08-06 17:38:51 -07:00
Andrew Waterman
4bfbe75d74 Avoid pipeline replays when fetch queue is full 2017-08-04 16:59:21 -07:00
Andrew Waterman
a45997d03f Separate I$ parity error from miss signal 
Handle parity errors with a pipeline flush rather than a faster
frontend replay, reducing a critical path.
 2017-08-04 16:59:21 -07:00
Andrew Waterman
f483bab4aa Fix I$ miss perfctr 
The old version was counting prefetches, too.
 2017-08-03 00:52:12 -07:00
Andrew Waterman
1be1433f04 Merge pull request #918 from freechipsproject/icache-prefetch 
Icache prefetch
 2017-08-02 21:22:20 -07:00
Andrew Waterman
2537d0d54e Optionally prefetch next I$ line into L2$ on miss 2017-08-02 17:10:56 -07:00
Andrew Waterman
9464c6db40 Mitigate(?) frontend critical path 2017-08-01 18:51:17 -07:00
Andrew Waterman
735701382f Mitigate some I$ response valid critical paths 2017-08-01 18:51:17 -07:00
Andrew Waterman
d811692c3b Mitigate I$->D$->I$ critical path 
This seemingly irrelevant change shaves several gate delays off the I$
tl.a.valid path.
 2017-07-31 01:43:04 -07:00
Andrew Waterman
acca0fccf5 Fix BTB not being refilled on some indirect jumps 
We are overloading the BTB-hit signal to mean that any part of the frontend
changed the control-flow, not just the BTB.  That's the right thing to do for
most of the control logic, but it means the BTB sometimes won't get refilled
when we'd like it to.  This commit makes the frontend use an invalid BTB entry
number when it, rather than the BTB, changes the control flow.  Since the
entry number is invalid, the BTB will treat it as a miss and refill itself.

This is kind of a hack, but a more palatable fix requires reworking the RVC
IBuf, which I don't have time for right now.
 2017-07-26 02:13:43 -07:00
Andrew Waterman
15878d4691 Perform some control-flow transfers within the Frontend 2017-07-25 15:19:16 -07:00
Henry Cook
4c595d175c Refactor package hierarchy and remove legacy bus protocol implementations (#845) 
* Refactors package hierarchy.

Additionally:
  - Removes legacy ground tests and configs
  - Removes legacy bus protocol implementations
  - Removes NTiles
  - Adds devices package
  - Adds more functions to util package
 2017-07-07 10:48:16 -07:00
Andrew Waterman
438abc76d2 Handle TL errors in L1 I$ 
Cache the error bit in the tag array; report precisely on access.
 2017-07-06 01:02:11 -07:00
Wesley W. Terpstra
fbcd6f0eb2 Revert "rocket: link itim to its cpu" 
This reverts commit 48390ed604.
 2017-06-28 23:10:57 -07:00
Henry Cook
6e5a4c687f diplomacy: a type of connect that always disables monitors (#828) 2017-06-28 21:48:10 -07:00
Wesley W. Terpstra
48390ed604 rocket: link itim to its cpu 2017-06-28 15:06:19 -07:00
Andrew Waterman
3e04a99f61 Refactor frontend exception passing 
Bundle them, and leverage regularity, so that if we have to add more
exceptions in the future, we don't need to change so much code.
 2017-06-28 02:09:18 -07:00
Andrew Waterman
25f585f2a9 Remove unused signal from TLB interface 2017-06-28 02:09:18 -07:00
Andrew Waterman
d5f80df0ae Allow speculative I$ refill to cacheable regions 
Backpedaling on 27b143013f.  Shaving
four cycles off of I$ miss penalty is obviously worth the HW cost.
 2017-06-28 02:09:18 -07:00
Colin Schmidt
675f183dd2 refactor ICache to be reusable by other frontends (#808) 
* refactor ICache to be reusable by other frontends

specifically one that would like to change the fetch width and number of
bytes in an instruction
 2017-06-20 08:21:01 -07:00
Andrew Waterman
8552c77972 Fix I$ reset regression FU-357 
Can't rely on s2 TLB response, so mask using s2_valid.
 2017-06-09 00:48:24 -07:00
Andrew Waterman
27b143013f Improve ITLB QoR 
- No need to check cacheability
- Remove a gate delay from PMP path
 2017-06-02 20:45:50 -07:00
Andrew Waterman
dbc5e7c494 Add TLB miss performance counters (#762) 2017-05-23 12:52:25 -07:00
Henry Cook
a19fc2549e tile: add tileBus xbar 2017-05-16 16:12:01 -07:00
Andrew Waterman
fa6ecdf813 Fix RVC/uncacheable instruction memory performance bug 
9c1d126965 was an incomplete fix, so
sometimes we were requesting pipeline replays when they weren't
necessary.
 2017-05-03 17:52:06 -07:00
Andrew Waterman
4efcb5a139 Increase frontend decoupling (#722) 
Reduce pathological RVC stalls
 2017-05-03 07:54:46 -07:00
Henry Cook
e99fa057ac cleanup scratchpad nodes 2017-04-27 14:02:05 -07:00
Andrew Waterman
e23ee274f6 Size hartid field with NTiles, not XLen 2017-04-26 20:11:43 -07:00
Andrew Waterman
418879a47f Add Instruction Tightly Integrated Memory 2017-04-26 19:35:35 -07:00
Wesley W. Terpstra
9c1d126965 Allow speculative fetch to uncacheable memory if it hits in I$ (#700) 
@aswaterman it's in
 2017-04-24 19:12:37 -07:00
Andrew Waterman
f2d4cb8152 Update RAS speculatively from fetch stage 2017-04-24 02:01:15 -07:00
Andrew Waterman
bf861293d9 Add ShiftQueue; use it 2017-04-24 02:01:15 -07:00
Andrew Waterman
d24d8ff84b Don't stall the frontend, making it easier to add more features later 2017-04-24 02:01:15 -07:00
Andrew Waterman
061a0adceb Fetch smaller parcels from the I$ 2017-04-24 02:01:15 -07:00
Andrew Waterman
410e9cf736 I$ bugfix, to be reworked 2017-03-31 12:17:41 -07:00
Andrew Waterman
069858a20c rocket: separate page faults from physical memory access exceptions 2017-03-27 16:37:09 -07:00
Andrew Waterman
723352c3e2 Mitigate some more PMP critical paths 2017-03-24 16:39:52 -07:00