riscv/rocket-chip
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380 Commits

Author SHA1 Message Date
Andrew Waterman
8087a205cc Remove redundant check in interrupt priority encoding 
chooseInterrupts already sorts M interrupts above S interrupts.
 2017-08-17 22:23:42 -07:00
Andrew Waterman
cbe7c51b50 Respect ISA requirements on interrupt priority order 
a62e76cb16
 2017-08-17 21:27:08 -07:00
Andrew Waterman
e945f6e265 Merge pull request #955 from freechipsproject/fix-acquire-before-release 
Fix acquire before release
 2017-08-13 18:29:58 -07:00
Megan Wachs
88332bd885 max-core-cycles: Add a +max-core-cycles PlusArg 2017-08-13 15:47:14 -07:00
Andrew Waterman
3cbc5262ec Don't permit new acquires until the release queue is drained 
If the queue is not empty before a dirty miss, C could block D.
I haven't seen this in the wild, but it could happen because of
dirty probe responses backed up in the queue.
 2017-08-13 13:18:45 -07:00
Andrew Waterman
0190724492 Actually use the C-channel acquire-before-release queue 
oops...
 2017-08-13 13:03:35 -07:00
Andrew Waterman
7387f2a93a Don't block D-channel when handling a probe 
This is an acquire-before-release regression.
 2017-08-12 16:13:24 -07:00
Andrew Waterman
604abd5b07 Only report ECC errors when the RAM was actually read 2017-08-12 15:28:03 -07:00
Andrew Waterman
18fb052fc9 DRY 2017-08-12 15:27:30 -07:00
Andrew Waterman
176110b6d3 Don't trigger ECC writebacks when a release is in flight 2017-08-12 15:23:57 -07:00
Andrew Waterman
0a591c5b5b Roll back use of UIntToOH1 (#946) 
These appear to be equivalent, but the old one seems to fail in Vivado and
this one seems to pass.  This is not yet conclusive.
 2017-08-09 18:39:47 -07:00
Andrew Waterman
721770244e Fix IBuf bug 
Don't examine a packet's xcpt signal if it might be invalid.  In this case,
the correct fix is to not examine xcpt at all; the deleted code was vestigial.
(Note, the other use of xcpt(j+1) in this code is indeed safe.)
 2017-08-09 09:47:51 -07:00
Andrew Waterman
809c7e8551 Don't merge stores that manifest WAW hazards 
The following sequence would drop the first store when eccBytes=4:

    sb x0, 0(t0)
    nop
    sb x0, 4(t0)
    nop
    sb x0, 1(t0)

Because the first and second store are to different ECC granules, the
hazard check correctly allowed the second one to proceed, but the third
was merged with the second, even though it conflicted with the first.
So, don't allow the third to be merged with the second, since the second
stored to a different ECC granule.
 2017-08-08 15:19:05 -07:00
Andrew Waterman
82e13443b2 Merge pull request #937 from freechipsproject/critical-paths 
Perform tag error detectoin/correction in same cycle as RAM
 2017-08-08 15:03:28 -07:00
Andrew Waterman
7935c61c19 Don't report to the DTIM that data is cacheable 
Otherwise, it will attempt to perform AMOs where they're unsupported!
 2017-08-08 11:55:04 -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
e92981b0bd DRY 2017-08-08 11:46:38 -07:00
Andrew Waterman
62ccba304c Perform tag error detectoin/correction in same cycle as RAM 
The tag RAMs tend to be fast, so take up some of the slack.
This makes s2_nack faster.
 2017-08-08 10:21:30 -07:00
Palmer Dabbelt
6d1d285464 Merge pull request #933 from freechipsproject/cinst 
Print out the compressed instruction when executing one
 2017-08-07 21:40:10 -07:00
Andrew Waterman
402907990c Revert "Remove one gate from D$ ECC check" 
This reverts commit 7d94074b05, which
works fine with optimistic behavioral RAMs but not real ones.
 2017-08-07 17:33:20 -07:00
Palmer Dabbelt
fc0d5fcf98 Print out the compressed instruction when executing one 2017-08-07 17:21:53 -07:00
Andrew Waterman
658e36f98b Reduce fanout on frontend io.cpu.req.valid signal 2017-08-06 17:38:51 -07:00
Andrew Waterman
7d94074b05 Remove one gate from D$ ECC check 
The D$ corrects via writeback, so which word the error was in doesn't
matter, as the entire line is corrected.
 2017-08-06 17:36:53 -07:00
Andrew Waterman
83875e3a0c Only flush D$ on FENCE.I if it won't always be probed on I$ miss 2017-08-05 14:22:40 -07:00
Andrew Waterman
991e16de92 Remove probe address mux from TLB response path 2017-08-05 12:57:38 -07:00
Andrew Waterman
b9b4142bb4 Get s2_nack off the critical path 
We were using it to compute the next PC on flush vs. replay (which require
PC+4 and PC, respectively).  This fix gets rid of the adder altogether by
reusing the M-stage PC in the flush case, which by construction holds PC+4.
 2017-08-05 00:30:36 -07:00
Andrew Waterman
6112adfbb0 Get L2 TLB tag/parity check off the D$ arbitration path 2017-08-04 17:01:51 -07:00
Andrew Waterman
8d97684555 Fix L2 TLB perfctr 
It was counting conflict misses but not cold misses.
 2017-08-04 17:01:31 -07:00
Andrew Waterman
df7f09b9ce Get I$ ECC check further off critical path 2017-08-04 16:59:21 -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
06a831310b Shave a gate delay off I$ backpressure path 
The deleted code was a holdover from Hwacha's vector fences.
 2017-08-04 13:12:43 -07:00
Andrew Waterman
ecc2ee366c Shave a few gate delays off IBuf control logic 
It takes a while for the pipeline to compute the stall signal, so avoid
using it until the last logic levels in the clock cycle.
 2017-08-04 13:12:43 -07:00
Andrew Waterman
7937db0c84 Merge pull request #919 from freechipsproject/imiss-perf-counter 
Fix I$ miss perfctr
 2017-08-04 01:04:23 -07:00
Andrew Waterman
ba4eecc0f0 Use UIntToOH1 (#921) 
Closes #920
 2017-08-03 14:55:39 -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
744cdb2f72 Make TLB report when it's safe to prefetch within a page 2017-08-02 17:09:38 -07:00
Andrew Waterman
7d2dd3769f Optimize a hazard check critical path 2017-08-02 14:27:25 -07:00
Andrew Waterman
2eb239d03f Add option to retime D$ way mux into subsequent pipeline stage 2017-08-01 23:59:20 -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
2ecea2ef60 Don't use a pipe queue on D$ TL A-channel 
This cuts an I$->D$ path.
 2017-08-01 15:17:07 -07:00
Andrew Waterman
5681693ccc Fix a D$ ready-valid signaling regression 
I broke this in 66d06460fa.
 2017-07-31 18:05:14 -07:00
Yunsup Lee
7adfd5c431 Merge pull request #906 from freechipsproject/critical-paths 
Mitigate I$->D$->I$ critical path
 2017-07-31 16:14:11 -07:00
Henry Cook
11332c1226 dcache: break potential combinatorial loop by making pstore_drain_on_miss more conservative 2017-07-31 14:03:30 -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
ac4339a8e7 Pass D$ backpressure to D-channel, rather than asserting 2017-07-29 11:48:36 -07:00
Andrew Waterman
edcd2c696c Avoid needless stall on E-channel back pressure 2017-07-29 11:47:58 -07:00