riscv/rocket-chip
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fix LR/SC atomicity violation

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note, it's still not starvation-free.
This commit is contained in:
Andrew Waterman 2013-04-05 19:13:38 -07:00
parent 8cbdeb2abf
commit 1abb9277db
1 changed files with 10 additions and 8 deletions
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18
rocket/src/main/scala/nbdcache.scala
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@ -872,8 +872,10 @@ class HellaCache(implicit conf: DCacheConfig, lnconf: LogicalNetworkConfiguratio
// load-reserved/store-conditional
val s2_lr_valid = Reg(resetVal = Bool(false))
val s2_lr_addr = Reg{UFix()}
val s2_lr_addr_match = s2_lr_addr === (s2_req.addr >> conf.offbits)
when (s2_valid_masked && s2_req.cmd === M_XLR) {
val (s2_lr, s2_sc) = (s2_req.cmd === M_XLR, s2_req.cmd === M_XSC)
val s2_lr_addr_match = s2_lr_valid && s2_lr_addr === (s2_req.addr >> conf.offbits)
val s2_sc_fail = s2_sc && !s2_lr_addr_match
when ((s2_valid_masked && s2_hit || s2_replay) && s2_lr) {
s2_lr_valid := true
s2_lr_addr := s2_req.addr >> conf.offbits
}
@ -898,7 +900,7 @@ class HellaCache(implicit conf: DCacheConfig, lnconf: LogicalNetworkConfiguratio
val s2_data_correctable = AVec(s2_data_decoded.map(_.correctable)).toBits()(s2_word_idx)
// store/amo hits
s3_valid := (s2_valid_masked && s2_hit || s2_replay) && isWrite(s2_req.cmd)
s3_valid := (s2_valid_masked && s2_hit && !s2_sc_fail || s2_replay) && isWrite(s2_req.cmd)
val amoalu = new AMOALU
when ((s2_valid || s2_replay) && (isWrite(s2_req.cmd) || s2_data_correctable)) {
s3_req := s2_req
@ -978,7 +980,7 @@ class HellaCache(implicit conf: DCacheConfig, lnconf: LogicalNetworkConfiguratio
val s4_valid = Reg(s3_valid, resetVal = Bool(false))
val s4_req = RegEn(s3_req, s3_valid && metaReadArb.io.out.valid)
val bypasses = List(
(s2_valid_masked || s2_replay, s2_req, amoalu.io.out),
(s2_valid_masked && !s2_sc_fail || s2_replay, s2_req, amoalu.io.out),
(s3_valid, s3_req, s3_req.data),
(s4_valid, s4_req, s4_req.data)
).map(r => (r._1 && (s1_addr >> conf.wordoffbits === r._2.addr >> conf.wordoffbits) && isWrite(r._2.cmd), r._3))
@ -1026,13 +1028,13 @@ class HellaCache(implicit conf: DCacheConfig, lnconf: LogicalNetworkConfiguratio
io.cpu.req.ready := Bool(false)
}
val s2_read = isRead(s2_req.cmd) || s2_req.cmd === M_XSC
io.cpu.resp.valid := s2_read && (s2_replay || s2_valid_masked && s2_hit) && !s2_data_correctable
val s2_do_resp = isRead(s2_req.cmd) || s2_sc
io.cpu.resp.valid := s2_do_resp && (s2_replay || s2_valid_masked && s2_hit) && !s2_data_correctable
io.cpu.resp.bits.nack := s2_valid && s2_nack
io.cpu.resp.bits := s2_req
io.cpu.resp.bits.replay := s2_replay && s2_read
io.cpu.resp.bits.replay := s2_replay && s2_do_resp
io.cpu.resp.bits.data := loadgen.word
io.cpu.resp.bits.data_subword := Mux(s2_req.cmd === M_XSC, !s2_lr_addr_match, loadgen.byte)
io.cpu.resp.bits.data_subword := Mux(s2_sc, s2_sc_fail, loadgen.byte)
io.cpu.resp.bits.store_data := s2_req.data
io.mem.grant_ack <> mshr.io.mem_finish