riscv/rocket-chip
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dcache: break potential combinatorial loop by making pstore_drain_on_miss more conservative

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This commit is contained in:
Henry Cook 2017-07-31 14:03:30 -07:00
parent ea1840c4b1
commit 11332c1226
1 changed files with 4 additions and 5 deletions
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9
src/main/scala/rocket/DCache.scala
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@ -230,7 +230,7 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
val s2_valid_miss = s2_valid_masked && s2_readwrite && !s2_meta_error && !s2_hit && !release_ack_wait val s2_valid_miss = s2_valid_masked && s2_readwrite && !s2_meta_error && !s2_hit && !release_ack_wait
val s2_valid_cached_miss = s2_valid_miss && !s2_uncached && !uncachedInFlight.asUInt.orR val s2_valid_cached_miss = s2_valid_miss && !s2_uncached && !uncachedInFlight.asUInt.orR
val s2_victimize = Bool(!usingDataScratchpad) && (s2_valid_cached_miss || s2_valid_data_error || s2_flush_valid) val s2_victimize = Bool(!usingDataScratchpad) && (s2_valid_cached_miss || s2_valid_data_error || s2_flush_valid)
val s2_valid_uncached = s2_valid_miss && s2_uncached val s2_valid_uncached_pending = s2_valid_miss && s2_uncached && !uncachedInFlight.asUInt.andR
val s2_victim_way = Mux(s2_hit_valid && !s2_flush_valid_pre_tag_ecc, s2_hit_way, UIntToOH(RegEnable(s1_victim_way, s1_valid_not_nacked || s1_flush_valid))) val s2_victim_way = Mux(s2_hit_valid && !s2_flush_valid_pre_tag_ecc, s2_hit_way, UIntToOH(RegEnable(s1_victim_way, s1_valid_not_nacked || s1_flush_valid)))
val s2_victim_tag = Mux(s2_valid_data_error, s2_req.addr >> untagBits, RegEnable(s1_victim_meta.tag, s1_valid_not_nacked || s1_flush_valid)) val s2_victim_tag = Mux(s2_valid_data_error, s2_req.addr >> untagBits, RegEnable(s1_victim_meta.tag, s1_valid_not_nacked || s1_flush_valid))
val s2_victim_state = Mux(s2_hit_valid && !s2_flush_valid, s2_hit_state, RegEnable(s1_victim_meta.coh, s1_valid_not_nacked || s1_flush_valid)) val s2_victim_state = Mux(s2_hit_valid && !s2_flush_valid, s2_hit_state, RegEnable(s1_victim_meta.coh, s1_valid_not_nacked || s1_flush_valid))
@ -238,7 +238,7 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
val (s2_prb_ack_data, s2_report_param, probeNewCoh)= s2_probe_state.onProbe(probe_bits.param) val (s2_prb_ack_data, s2_report_param, probeNewCoh)= s2_probe_state.onProbe(probe_bits.param)
val (s2_victim_dirty, s2_shrink_param, voluntaryNewCoh) = s2_victim_state.onCacheControl(M_FLUSH) val (s2_victim_dirty, s2_shrink_param, voluntaryNewCoh) = s2_victim_state.onCacheControl(M_FLUSH)
val s2_update_meta = s2_hit_state =/= s2_new_hit_state val s2_update_meta = s2_hit_state =/= s2_new_hit_state
io.cpu.s2_nack := s2_valid && !s2_valid_hit && !(s2_valid_uncached && tl_out_a.ready && !uncachedInFlight.asUInt.andR) io.cpu.s2_nack := s2_valid && !s2_valid_hit && !(s2_valid_uncached_pending && tl_out_a.ready)
when (io.cpu.s2_nack || (s2_valid_hit && s2_update_meta)) { s1_nack := true } when (io.cpu.s2_nack || (s2_valid_hit && s2_update_meta)) { s1_nack := true }
// tag updates on ECC errors // tag updates on ECC errors
@ -286,7 +286,7 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
any_pstore_valid := pstore1_valid || pstore2_valid any_pstore_valid := pstore1_valid || pstore2_valid
val pstore_drain_structural = pstore1_valid && pstore2_valid && ((s1_valid && s1_write) || pstore1_rmw) val pstore_drain_structural = pstore1_valid && pstore2_valid && ((s1_valid && s1_write) || pstore1_rmw)
val pstore_drain_opportunistic = !(io.cpu.req.valid && s0_needsRead) val pstore_drain_opportunistic = !(io.cpu.req.valid && s0_needsRead)
val pstore_drain_on_miss = releaseInFlight || io.cpu.s2_nack val pstore_drain_on_miss = releaseInFlight || (s2_valid && !s2_valid_hit && !s2_valid_uncached_pending)
val pstore_drain = !pstore1_merge && val pstore_drain = !pstore1_merge &&
(Bool(usingRMW) && pstore_drain_structural || (Bool(usingRMW) && pstore_drain_structural ||
(((pstore1_valid && !pstore1_rmw) || pstore2_valid) && (pstore_drain_opportunistic || pstore_drain_on_miss))) (((pstore1_valid && !pstore1_rmw) || pstore2_valid) && (pstore_drain_opportunistic || pstore_drain_on_miss)))
@ -367,8 +367,7 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
Wire(new TLBundleA(edge.bundle)) Wire(new TLBundleA(edge.bundle))
} }
tl_out_a.valid := (s2_valid_cached_miss && (Bool(cacheParams.acquireBeforeRelease) || !s2_victim_dirty)) || tl_out_a.valid := (s2_valid_cached_miss && (Bool(cacheParams.acquireBeforeRelease) || !s2_victim_dirty)) || s2_valid_uncached_pending
(s2_valid_uncached && !uncachedInFlight.asUInt.andR)
tl_out_a.bits := Mux(!s2_uncached, acquire, Mux(!s2_write, get, Mux(!s2_read, put, atomics))) tl_out_a.bits := Mux(!s2_uncached, acquire, Mux(!s2_write, get, Mux(!s2_read, put, atomics)))
// Set pending bits for outstanding TileLink transaction // Set pending bits for outstanding TileLink transaction