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fix(LoadUnit): misalign load wakeup not enter loadunit #4333

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Mar 3, 2025
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fix(LoadUnit): misalign load wakeup not enter loadunit #4333

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38 changes: 19 additions & 19 deletions src/main/scala/xiangshan/mem/pipeline/LoadUnit.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ import utils._
import utility._
import xiangshan._
import xiangshan.ExceptionNO._
import xiangshan.backend.Bundles.{DynInst, MemExuInput, MemExuOutput}
import xiangshan.backend.Bundles.{DynInst, MemExuInput, MemExuOutput, connectSamePort}
import xiangshan.backend.fu.PMPRespBundle
import xiangshan.backend.fu.FuConfig._
import xiangshan.backend.fu.FuType
Expand Down Expand Up @@ -330,7 +330,7 @@ class LoadUnit(implicit p: Parameters) extends XSModule
s0_src_select_vec(fast_rep_idx) || s0_src_select_vec(mmio_idx) ||
s0_src_select_vec(nc_idx)
s0_valid := !s0_kill && (s0_src_select_vec(nc_idx) || ((
s0_src_valid_vec(mab_idx) ||
s0_src_valid_vec(mab_idx) && !io.misalign_ldin.bits.misalignNeedWakeUp ||
s0_src_valid_vec(super_rep_idx) ||
s0_src_valid_vec(fast_rep_idx) ||
s0_src_valid_vec(lsq_rep_idx) ||
Expand Down Expand Up @@ -1156,6 +1156,12 @@ class LoadUnit(implicit p: Parameters) extends XSModule
s2_mmio_req.valid := RegNextN(io.lsq.uncache.fire, 2, Some(false.B))
s2_mmio_req.bits := RegNextN(io.lsq.uncache.bits, 2)

val s3_misalign_wakeup_req = Wire(Valid(new LqWriteBundle))
val s3_misalign_wakeup_req_bits = WireInit(0.U.asTypeOf(new LqWriteBundle))
connectSamePort(s3_misalign_wakeup_req_bits, io.misalign_ldin.bits)
s3_misalign_wakeup_req.valid := RegNextN(io.misalign_ldin.bits.misalignNeedWakeUp && io.misalign_ldin.fire, 3, Some(false.B))
s3_misalign_wakeup_req.bits := RegNextN(s3_misalign_wakeup_req_bits, 3)

s2_kill := s2_in.uop.robIdx.needFlush(io.redirect)
s2_ready := !s2_valid || s2_kill || s3_ready
when (s1_fire) { s2_valid := true.B }
Expand Down Expand Up @@ -1282,11 +1288,10 @@ class LoadUnit(implicit p: Parameters) extends XSModule
!s2_tlb_miss &&
!s2_fwd_fail &&
(s2_dcache_fast_rep || s2_nuke_fast_rep) &&
s2_troublem &&
!s2_in.misalignNeedWakeUp
s2_troublem

// need allocate new entry
val s2_can_query = !((s2_dcache_fast_rep || s2_nuke) && !s2_in.misalignNeedWakeUp) && s2_troublem
val s2_can_query = !(s2_dcache_fast_rep || s2_nuke) && s2_troublem

val s2_data_fwded = s2_dcache_miss && s2_full_fwd

Expand All @@ -1303,8 +1308,8 @@ class LoadUnit(implicit p: Parameters) extends XSModule

val s2_fwd_vp_match_invalid = io.lsq.forward.matchInvalid || io.sbuffer.matchInvalid || io.ubuffer.matchInvalid
val s2_vp_match_fail = s2_fwd_vp_match_invalid && s2_troublem
val s2_safe_wakeup = !s2_out.rep_info.need_rep && !s2_mmio && (!s2_in.nc || s2_nc_with_data) && !s2_mis_align && !s2_real_exception || s2_in.misalignNeedWakeUp // don't need to replay and is not a mmio\misalign no data
val s2_safe_writeback = s2_real_exception || s2_safe_wakeup || s2_vp_match_fail || s2_in.misalignNeedWakeUp
val s2_safe_wakeup = !s2_out.rep_info.need_rep && !s2_mmio && (!s2_in.nc || s2_nc_with_data) && !s2_mis_align && !s2_real_exception // don't need to replay and is not a mmio\misalign no data
val s2_safe_writeback = s2_real_exception || s2_safe_wakeup || s2_vp_match_fail

// ld-ld violation require
io.lsq.ldld_nuke_query.req.valid := s2_valid
Expand Down Expand Up @@ -1513,7 +1518,7 @@ class LoadUnit(implicit p: Parameters) extends XSModule
// forwrad last beat
val s3_fast_rep_canceled = io.replay.valid && io.replay.bits.forward_tlDchannel || io.misalign_ldin.valid || !io.dcache.req.ready

val s3_can_enter_lsq_valid = s3_valid && (!s3_fast_rep || s3_fast_rep_canceled) && !s3_in.feedbacked && !s3_in.misalignNeedWakeUp
val s3_can_enter_lsq_valid = s3_valid && (!s3_fast_rep || s3_fast_rep_canceled) && !s3_in.feedbacked
io.lsq.ldin.valid := s3_can_enter_lsq_valid
// TODO: check this --by hx
// io.lsq.ldin.valid := s3_valid && (!s3_fast_rep || !io.fast_rep_out.ready) && !s3_in.feedbacked && !s3_in.lateKill
Expand Down Expand Up @@ -1554,11 +1559,7 @@ class LoadUnit(implicit p: Parameters) extends XSModule
val s3_mab_sel_rep_cause = PriorityEncoderOH(s3_mab_rep_info.cause.asUInt)
val s3_misalign_rep_cause = WireInit(0.U.asTypeOf(s3_in.rep_info.cause))

s3_misalign_rep_cause := Mux(
s3_in.misalignNeedWakeUp,
0.U.asTypeOf(s3_mab_rep_info.cause.cloneType),
VecInit(s3_mab_sel_rep_cause.asBools)
)
s3_misalign_rep_cause := VecInit(s3_mab_sel_rep_cause.asBools)

when (s3_exception || s3_hw_err || s3_rep_frm_fetch || s3_frm_mabuf) {
s3_replayqueue_rep_cause := 0.U.asTypeOf(s3_lrq_rep_info.cause.cloneType)
Expand Down Expand Up @@ -1646,7 +1647,7 @@ class LoadUnit(implicit p: Parameters) extends XSModule
io.feedback_slow.bits.dataInvalidSqIdx := DontCare

// TODO: vector wakeup?
io.ldCancel.ld2Cancel := s3_valid && !s3_safe_wakeup && !s3_isvec && (!s3_frm_mabuf || s3_in.misalignNeedWakeUp)
io.ldCancel.ld2Cancel := s3_valid && !s3_safe_wakeup && !s3_isvec

val s3_ld_wb_meta = Mux(s3_valid, s3_out.bits, s3_mmio_req.bits)

Expand Down Expand Up @@ -1738,7 +1739,6 @@ class LoadUnit(implicit p: Parameters) extends XSModule
FuType.ldu.U
)

XSError(s3_valid && s3_in.misalignNeedWakeUp && !s3_frm_mabuf, "Only the needwakeup from the misalignbuffer may be high")
XSError(s3_valid && s3_vecout.isvec && s3_in.vecActive && !s3_vecout.mask.orR, "In vecActive, mask complement should not be 0")
// TODO: check this --hx
// io.ldout.valid := s3_out.valid && !s3_out.bits.uop.robIdx.needFlush(io.redirect) && !s3_vecout.isvec ||
Expand Down Expand Up @@ -1798,10 +1798,10 @@ class LoadUnit(implicit p: Parameters) extends XSModule
// io.lsq.uncache.valid && !io.lsq.uncache.bits.uop.robIdx.needFlush(io.redirect) && !s3_out.valid && io.lsq.uncache.bits.isVls
//io.lsq.uncache.valid && !io.lsq.uncache.bits.uop.robIdx.needFlush(io.redirect) && !s3_out.valid && !io.lsq.uncache.bits.isVls

io.misalign_ldout.valid := s3_valid && (!s3_fast_rep || s3_fast_rep_canceled) && s3_frm_mabuf
io.misalign_ldout.bits := io.lsq.ldin.bits
io.misalign_ldout.bits.data := Mux(s3_in.misalignWith16Byte, s3_merged_data_frm_pipe, s3_picked_data_frm_pipe(2))
io.misalign_ldout.bits.rep_info.cause := s3_misalign_rep_cause
io.misalign_ldout.valid := s3_valid && (!s3_fast_rep || s3_fast_rep_canceled) && s3_frm_mabuf || s3_misalign_wakeup_req.valid
io.misalign_ldout.bits := Mux(s3_misalign_wakeup_req.valid, s3_misalign_wakeup_req.bits, io.lsq.ldin.bits)
io.misalign_ldout.bits.data := s3_picked_data_frm_pipe(2)
io.misalign_ldout.bits.rep_info.cause := Mux(s3_misalign_wakeup_req.valid, 0.U.asTypeOf(s3_in.rep_info.cause), s3_misalign_rep_cause)

// fast load to load forward
if (EnableLoadToLoadForward) {
Expand Down
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