riscv/rocket-chip
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5d1165c850
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167 Commits

Author SHA1 Message Date
Andrew Waterman
5d1165c850 Express PMP mask generator using a carry chain 
This allows it to be optimized like an adder, improving QoR when it
is on the critical path.
 2017-03-26 14:20:16 -07:00
Henry Cook
996a31364a rocket: remove hard-coded paddrBits (#610) 
Fall back on global variable but check that it is compatible with memory as seen from rocket's tilelink master port.
 2017-03-24 22:30:18 -07:00
Andrew Waterman
17b1ee3037 Default to 8 PMPs; support 0 PMPs 2017-03-24 16:39:52 -07:00
Andrew Waterman
97006ab396 Don't modulate PMP privilege on passsthrough when !usingVM 2017-03-24 16:39:52 -07:00
Andrew Waterman
3f0d2fe826 Instantiate PTW unconditionally 
This keeps the PMP datapaths intact.  The PTW itself will get optimized
away for the !usingVM case.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
30415215b8 Don't check for exceptions on ScratchpadSlavePort accesses 2017-03-24 16:39:52 -07:00
Andrew Waterman
ccd5bc9a91 Improve QoR of PMP homogeneity checker 2017-03-24 16:39:52 -07:00
Andrew Waterman
e9cadf29d2 Improve DCache MMIO QoR 
No need to store the cmd field.  From the perspective of the cache, all
MMIO responses that have data can be treated the same as loads.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
fb6498f2c3 Use Reg(Vec) instead of Seq(Reg) for DCache MMIO 2017-03-24 16:39:52 -07:00
Andrew Waterman
0538dc77ce For D$, use source 0 through N-1 for MMIO, not 1 through N 
This makes the code a bit cleaner.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
3951e57789 Force each TLB entry into its own clock-gate group 
This ameliorates a PMP critical path.

I can't figure out how to do this without asUInt/asTypeOf.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
8d7f1d777e Fix an embarrassing typo in the PMPHeterogeneityChecker 2017-03-24 16:39:52 -07:00
Andrew Waterman
10c39cb8d6 Disable mprv in D-mode 2017-03-24 16:39:52 -07:00
Andrew Waterman
d3bda9574c Put page homogeneity checker in PMP 
Avoids redundancy between ITLB and DTLB
 2017-03-24 16:39:52 -07:00
Andrew Waterman
9e05200e51 Don't require that PMP ranges be aligned to access size 
e.g., if a range permits access to 0x0-0xb, allow 8-byte accesses 0x0-0x7.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
29e67279ba add comments 2017-03-24 16:39:52 -07:00
Andrew Waterman
4c8be13a4d Improve homogeneity circuit QoR 2017-03-24 16:39:52 -07:00
Andrew Waterman
59d6afa132 mideleg/medeleg not present without less-privileged traps 2017-03-24 16:39:52 -07:00
Andrew Waterman
38808f55d5 Share PMP mask gen between I$ and D$ 2017-03-24 16:39:52 -07:00
Andrew Waterman
86d84959cf More WIP on PMP 2017-03-24 16:39:52 -07:00
Andrew Waterman
2888779422 Flush pipeline from WB stage, not MEM 
Fixes sptbr write -> instruction translation hazard.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
44ca3b60ab Retime PTW response valid bits 
It's not just to save the gate delay; it also reduces wire delay by
allowing the flops to be closer to their respective TLBs.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
a03556220c Default TLB size = 32 
@davidbiancolin
 2017-03-24 16:39:52 -07:00
Andrew Waterman
1875407316 Get TLB permission checks off D$ clock gating critical path 2017-03-24 16:39:52 -07:00
Andrew Waterman
a4164348b4 Expose MXR to S-mode 2017-03-24 16:39:52 -07:00
Andrew Waterman
0380aed329 PUM -> SUM 2017-03-24 16:39:52 -07:00
Andrew Waterman
29414f3a23 Simplify interrupt-stack discipline 
f2ed45b179
 2017-03-24 16:39:52 -07:00
Andrew Waterman
723352c3e2 Mitigate some more PMP critical paths 2017-03-24 16:39:52 -07:00
Andrew Waterman
7484f27ed3 Don't gate exception-cause pipeline registers separately 
They are too narrow to justify gating separately from the other pipeline
registers (and one of the clock gates was on the PMP critical path).
 2017-03-24 16:39:52 -07:00
Andrew Waterman
487b8db5ef Address some PMP critical paths 2017-03-24 16:39:52 -07:00
Andrew Waterman
03fb334c4c Take mprv calculation off critical path 2017-03-24 16:39:52 -07:00
Andrew Waterman
f0796f0509 Pass correct access size information to PMP checker 2017-03-24 16:39:52 -07:00
Andrew Waterman
a6874c03f7 Remove DecoupledTLB 2017-03-24 16:39:52 -07:00
Andrew Waterman
78f9f6b9ef When SFENCE.VMA has rs2 != x0, don't flush global mappings 2017-03-24 16:39:52 -07:00
Andrew Waterman
1b950128e1 PTW should always use S-mode privilege 
If an exception occurs while a page-table walk is coincidentally in
progress (e.g., an illegal instruction executes during data TLB refill),
then the processor might enter M-mode.  However, the PTW's accesses
should proceed without M privilege, to avoid bypassing PMPs.

Note, the same argument doesn't apply to the nonblocking cache's replay
queues, because those accesses have already been checked against the PMPs.
The cache correctly ignores access exceptions reported on replays,
provided no exceptions were reported on the initial access.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
aace526857 WIP on PMP 2017-03-24 16:39:52 -07:00
Andrew Waterman
b1b405404d Set PRV=M when entering debug mode 
Debug mode mostly behaves like M-mode, so this approach avoids having
to check the debug bit in most permission checks.
 2017-03-24 16:39:52 -07:00
Andrew Waterman
cf168e419b Support SFENCE.VMA rs1 argument 
This one's a little invasive.  To flush a specific entry from the TLB, you
need to reuse its CAM port.  Since the TLB lookup can be on the critical
path, we wish to avoid muxing in another address.

This is simple on the data side, where the datapath already carries rs1 to
the TLB (it's the same path as the AMO address calculation).  It's trickier
for the I$, where the TLB lookup address comes from the fetch stage PC.
The trick is to temporarily redirect the PC to rs1, then redirect the PC
again to the instruction after SFENCE.VMA.
 2017-03-24 16:39:52 -07:00
Henry Cook
055b8ba1f0 rocket: avoid LinkedHashMap.keys to preserve traversal order (#603) 2017-03-22 14:38:33 -07:00
Andrew Waterman
3609254e4a There's no structural hazard on MMIO store responses 
So don't stall as though there were.
 2017-03-21 14:17:32 -07:00
Yunsup Lee
5eae7e1da4 make DCache s1_nack less conservative for pipelined MMIO requests 2017-03-21 11:16:51 -07:00
Wesley W. Terpstra
4c00066746 rocket: describe dcache as two clients (fifo+cached) 2017-03-21 11:16:51 -07:00
Wesley W. Terpstra
278f6fea24 tilelink2: define is{Request,Response} based on spec 2017-03-20 13:41:02 -07:00
Wesley W. Terpstra
0c92283a61 rocket icache: tie off b ready 2017-03-19 17:18:50 -07:00
Andrew Waterman
d6f571cbbb Implement mstatus.TSR 2017-03-13 14:50:06 -07:00
Andrew Waterman
1fea0460ba Support superpage entries in TLB 2017-03-13 14:50:06 -07:00
Andrew Waterman
2d267b4940 Support corner cases in TLBPermissions 
Don't crap out if the yes-set or no-set is empty.
 2017-03-13 14:50:06 -07:00
Wesley W. Terpstra
c847559853 TLB: add a helper API to determine homogeneous page permissions 2017-03-13 14:50:06 -07:00
Henry Cook
dbc8f4b30b last => done 2017-03-10 15:58:38 -08:00
Andrew Waterman
380c10f7bd Zap conflicting TLB entries, preparing for superpage support 
Superpages create the possibility that two entries in the TLB may match.
This corresponds to a software bug, but we can't return complete garbage;
we must return either the old translation or the new translation.  This
isn't compatible with the Mux1H approach.  So, flush the TLB and report
a miss on duplicate entries.
 2017-03-10 15:58:23 -08:00