xref: /XiangShan/src/main/scala/xiangshan/mem/pipeline/StoreUnit.scala (revision 0466583513e4c1ddbbb566b866b8963635acb20f)
1/***************************************************************************************
2* Copyright (c) 2020-2021 Institute of Computing Technology, Chinese Academy of Sciences
3* Copyright (c) 2020-2021 Peng Cheng Laboratory
4*
5* XiangShan is licensed under Mulan PSL v2.
6* You can use this software according to the terms and conditions of the Mulan PSL v2.
7* You may obtain a copy of Mulan PSL v2 at:
8*          http://license.coscl.org.cn/MulanPSL2
9*
10* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
11* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
12* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
13*
14* See the Mulan PSL v2 for more details.
15***************************************************************************************/
16
17package xiangshan.mem
18
19import chipsalliance.rocketchip.config.Parameters
20import chisel3._
21import chisel3.util._
22import utils._
23import utility._
24import xiangshan.ExceptionNO._
25import xiangshan._
26import xiangshan.backend.fu.PMPRespBundle
27import xiangshan.backend.rob.DebugLsInfoBundle
28import xiangshan.cache.mmu.{TlbCmd, TlbReq, TlbRequestIO, TlbResp}
29
30class StoreUnit(implicit p: Parameters) extends XSModule {
31  val io = IO(new Bundle() {
32    val redirect        = Flipped(ValidIO(new Redirect))
33    val stin            = Flipped(Decoupled(new ExuInput))
34    val issue           = Valid(new ExuInput)
35    val tlb             = new TlbRequestIO()
36    val pmp             = Flipped(new PMPRespBundle())
37    val rsIdx           = Input(UInt(log2Up(IssQueSize).W))
38    val isFirstIssue    = Input(Bool())
39    val lsq             = ValidIO(new LsPipelineBundle)
40    val lsq_replenish   = Output(new LsPipelineBundle())
41    val feedback_slow   = ValidIO(new RSFeedback)
42    val stld_nuke_query = Valid(new StoreNukeQueryIO)
43    val stout           = DecoupledIO(new ExuOutput) // writeback store
44    // store mask, send to sq in store_s0
45    val st_mask_out     = Valid(new StoreMaskBundle)
46    val debug_ls        = Output(new DebugLsInfoBundle)
47  })
48
49  val s1_ready, s2_ready, s3_ready = WireInit(false.B)
50
51  // Pipeline
52  // --------------------------------------------------------------------------------
53  // stage 0
54  // --------------------------------------------------------------------------------
55  // generate addr, use addr to query DCache and DTLB
56  val s0_valid        = io.stin.valid
57  val s0_in           = io.stin.bits
58  val s0_isFirstIssue = io.isFirstIssue
59  val s0_rsIdx        = io.rsIdx
60  val s0_out          = Wire(new LsPipelineBundle)
61  val s0_kill         = s0_in.uop.robIdx.needFlush(io.redirect)
62  val s0_can_go       = s1_ready
63  val s0_fire         = s0_valid && !s0_kill && s0_can_go
64
65  // generate addr
66  // val saddr = s0_in.bits.src(0) + SignExt(s0_in.bits.uop.ctrl.imm(11,0), VAddrBits)
67  val imm12 = WireInit(s0_in.uop.ctrl.imm(11,0))
68  val saddr_lo = s0_in.src(0)(11,0) + Cat(0.U(1.W), imm12)
69  val saddr_hi = Mux(saddr_lo(12),
70    Mux(imm12(11), s0_in.src(0)(VAddrBits-1, 12), s0_in.src(0)(VAddrBits-1, 12)+1.U),
71    Mux(imm12(11), s0_in.src(0)(VAddrBits-1, 12)+SignExt(1.U, VAddrBits-12), s0_in.src(0)(VAddrBits-1, 12)),
72  )
73  val s0_saddr = Cat(saddr_hi, saddr_lo(11,0))
74
75  io.tlb.req.valid             := s0_valid
76  io.tlb.req.bits.vaddr        := s0_saddr
77  io.tlb.req.bits.cmd          := TlbCmd.write
78  io.tlb.req.bits.size         := LSUOpType.size(s0_in.uop.ctrl.fuOpType)
79  io.tlb.req.bits.kill         := DontCare
80  io.tlb.req.bits.memidx.is_ld := false.B
81  io.tlb.req.bits.memidx.is_st := true.B
82  io.tlb.req.bits.memidx.idx   := s0_in.uop.sqIdx.value
83  io.tlb.req.bits.debug.robIdx := s0_in.uop.robIdx
84  io.tlb.req.bits.no_translate := false.B
85  io.tlb.req.bits.debug.pc     := s0_in.uop.cf.pc
86  io.tlb.req.bits.debug.isFirstIssue := s0_isFirstIssue
87  io.tlb.req_kill              := false.B
88
89  s0_out              := DontCare
90  s0_out.vaddr        := s0_saddr
91  // Now data use its own io
92  // s1_out.data := genWdata(s1_in.src(1), s1_in.uop.ctrl.fuOpType(1,0))
93  s0_out.data         := s0_in.src(1) // FIXME: remove data from pipeline
94  s0_out.uop          := s0_in.uop
95  s0_out.miss         := DontCare
96  s0_out.rsIdx        := s0_rsIdx
97  s0_out.mask         := genVWmask(s0_saddr, s0_in.uop.ctrl.fuOpType(1,0))
98  s0_out.isFirstIssue := s0_isFirstIssue
99  s0_out.isHWPrefetch := false.B // TODO
100  s0_out.wlineflag    := s0_in.uop.ctrl.fuOpType === LSUOpType.cbo_zero
101  when(s0_valid && s0_isFirstIssue) {
102    s0_out.uop.debugInfo.tlbFirstReqTime := GTimer()
103  }
104
105  // exception check
106  val s0_addr_aligned = LookupTree(s0_in.uop.ctrl.fuOpType(1,0), List(
107    "b00".U   -> true.B,              //b
108    "b01".U   -> (s0_out.vaddr(0) === 0.U),   //h
109    "b10".U   -> (s0_out.vaddr(1,0) === 0.U), //w
110    "b11".U   -> (s0_out.vaddr(2,0) === 0.U)  //d
111  ))
112  s0_out.uop.cf.exceptionVec(storeAddrMisaligned) := !s0_addr_aligned
113
114  io.st_mask_out.valid       := s0_valid
115  io.st_mask_out.bits.mask   := s0_out.mask
116  io.st_mask_out.bits.sqIdx  := s0_out.uop.sqIdx
117
118  io.stin.ready := s1_ready
119
120  // Pipeline
121  // --------------------------------------------------------------------------------
122  // stage 1
123  // --------------------------------------------------------------------------------
124  // TLB resp (send paddr to dcache)
125  val s1_valid  = RegInit(false.B)
126  val s1_in     = RegEnable(s0_out, s0_fire)
127  val s1_out    = Wire(new LsPipelineBundle)
128  val s1_kill   = Wire(Bool())
129  val s1_can_go = s2_ready
130  val s1_fire   = s1_valid && !s1_kill && s1_can_go
131
132  // mmio cbo decoder
133  val s1_mmio_cbo  = s1_in.uop.ctrl.fuOpType === LSUOpType.cbo_clean ||
134                     s1_in.uop.ctrl.fuOpType === LSUOpType.cbo_flush ||
135                     s1_in.uop.ctrl.fuOpType === LSUOpType.cbo_inval
136  val s1_paddr     = io.tlb.resp.bits.paddr(0)
137  val s1_tlb_miss  = io.tlb.resp.bits.miss
138  val s1_mmio      = s1_mmio_cbo
139  val s1_exception = ExceptionNO.selectByFu(s1_out.uop.cf.exceptionVec, staCfg).asUInt.orR
140  s1_kill := s1_in.uop.robIdx.needFlush(io.redirect) || s1_tlb_miss
141
142  s1_ready := !s1_valid || s1_kill || s2_ready
143  io.tlb.resp.ready := true.B // TODO: why dtlbResp needs a ready?
144  when (s0_fire) { s1_valid := true.B }
145  .elsewhen (s1_fire) { s1_valid := false.B }
146  .elsewhen (s1_kill) { s1_valid := false.B }
147
148  // st-ld violation dectect request.
149  io.stld_nuke_query.valid       := s1_valid && !s1_tlb_miss
150  io.stld_nuke_query.bits.robIdx := s1_in.uop.robIdx
151  io.stld_nuke_query.bits.paddr  := s1_paddr
152  io.stld_nuke_query.bits.mask   := s1_in.mask
153
154  // Send TLB feedback to store issue queue
155  // Store feedback is generated in store_s1, sent to RS in store_s2
156  io.feedback_slow.valid           := s1_fire
157  io.feedback_slow.bits.hit        := !s1_tlb_miss
158  io.feedback_slow.bits.flushState := io.tlb.resp.bits.ptwBack
159  io.feedback_slow.bits.rsIdx      := s1_in.rsIdx
160  io.feedback_slow.bits.sourceType := RSFeedbackType.tlbMiss
161  XSDebug(io.feedback_slow.valid,
162    "S1 Store: tlbHit: %d robIdx: %d\n",
163    io.feedback_slow.bits.hit,
164    io.feedback_slow.bits.rsIdx
165  )
166  io.feedback_slow.bits.dataInvalidSqIdx := DontCare
167
168  // issue
169  io.issue.valid := s1_valid && !s1_tlb_miss
170  io.issue.bits  := RegEnable(s0_in, s0_valid)
171
172  // rs feedback
173  val s1_feedback = Wire(Valid(new RSFeedback))
174  s1_feedback.valid                 := s1_valid & !s1_in.isHWPrefetch
175  s1_feedback.bits.hit              := !s1_tlb_miss
176  s1_feedback.bits.flushState       := io.tlb.resp.bits.ptwBack
177  s1_feedback.bits.rsIdx            := s1_out.rsIdx
178  s1_feedback.bits.sourceType       := RSFeedbackType.tlbMiss
179  s1_feedback.bits.dataInvalidSqIdx := DontCare
180  XSDebug(s1_feedback.valid,
181    "S1 Store: tlbHit: %d robIdx: %d\n",
182    s1_feedback.bits.hit,
183    s1_feedback.bits.rsIdx
184  )
185
186  // get paddr from dtlb, check if rollback is needed
187  // writeback store inst to lsq
188  s1_out        := s1_in
189  s1_out.paddr  := s1_paddr
190  s1_out.miss   := false.B
191  s1_out.mmio   := s1_mmio
192  s1_out.atomic := s1_mmio
193  s1_out.uop.cf.exceptionVec(storePageFault)   := io.tlb.resp.bits.excp(0).pf.st
194  s1_out.uop.cf.exceptionVec(storeAccessFault) := io.tlb.resp.bits.excp(0).af.st
195
196  io.lsq.valid     := s1_valid
197  io.lsq.bits      := s1_out
198  io.lsq.bits.miss := s1_tlb_miss
199
200  // write below io.out.bits assign sentence to prevent overwriting values
201  val s1_tlb_memidx = io.tlb.resp.bits.memidx
202  when(s1_tlb_memidx.is_st && io.tlb.resp.valid && !s1_tlb_miss && s1_tlb_memidx.idx === s1_out.uop.sqIdx.value) {
203    // printf("Store idx = %d\n", s1_tlb_memidx.idx)
204    s1_out.uop.debugInfo.tlbRespTime := GTimer()
205  }
206
207  // Pipeline
208  // --------------------------------------------------------------------------------
209  // stage 2
210  // --------------------------------------------------------------------------------
211  // mmio check
212  val s2_valid  = RegInit(false.B)
213  val s2_in     = RegEnable(s1_out, s1_fire)
214  val s2_out    = Wire(new LsPipelineBundle)
215  val s2_kill   = Wire(Bool())
216  val s2_can_go = s3_ready
217  val s2_fire   = s2_valid && !s2_kill && s2_can_go
218
219  s2_ready := !s2_valid || s2_kill || s3_ready
220  when (s1_fire) { s2_valid := true.B }
221  .elsewhen (s2_fire) { s2_valid := false.B }
222  .elsewhen (s2_kill) { s2_valid := false.B }
223
224  val s2_pmp = WireInit(io.pmp)
225  val s2_static_pm = RegNext(io.tlb.resp.bits.static_pm)
226  when (s2_static_pm.valid) {
227    s2_pmp.ld    := false.B
228    s2_pmp.st    := false.B
229    s2_pmp.instr := false.B
230    s2_pmp.mmio  := s2_static_pm.bits
231  }
232
233  val s2_exception = ExceptionNO.selectByFu(s2_out.uop.cf.exceptionVec, staCfg).asUInt.orR
234  val s2_mmio = s2_in.mmio || s2_pmp.mmio
235  s2_kill := (s2_mmio && !s2_exception) || s2_in.uop.robIdx.needFlush(io.redirect)
236
237  s2_out        := s2_in
238  s2_out.mmio   := s2_mmio && !s2_exception
239  s2_out.atomic := s2_in.atomic || s2_pmp.atomic
240  s2_out.uop.cf.exceptionVec(storeAccessFault) := s2_in.uop.cf.exceptionVec(storeAccessFault) || s2_pmp.st
241
242  // feedback tlb miss to RS in store_s2
243  io.feedback_slow.valid := RegNext(s1_feedback.valid && !s1_out.uop.robIdx.needFlush(io.redirect))
244  io.feedback_slow.bits  := RegNext(s1_feedback.bits)
245
246  // mmio and exception
247  io.lsq_replenish := s2_out
248
249  // Pipeline
250  // --------------------------------------------------------------------------------
251  // stage 3
252  // --------------------------------------------------------------------------------
253  // store write back
254  val s3_valid  = RegInit(false.B)
255  val s3_in     = RegEnable(s2_out, s2_fire)
256  val s3_out    = Wire(new ExuOutput)
257  val s3_kill   = s3_in.uop.robIdx.needFlush(io.redirect)
258  val s3_can_go = s3_ready
259  val s3_fire   = s3_valid && !s3_kill && s3_can_go
260
261  when (s2_fire) { s3_valid := (!s2_mmio || s2_exception) && !s2_out.isHWPrefetch  }
262  .elsewhen (s3_fire) { s3_valid := false.B }
263  .elsewhen (s3_kill) { s3_valid := false.B }
264
265  // wb: writeback
266  val SelectGroupSize   = RollbackGroupSize
267  val lgSelectGroupSize = log2Ceil(SelectGroupSize)
268  val TotalSelectCycles = scala.math.ceil(log2Ceil(LoadQueueRAWSize).toFloat / lgSelectGroupSize).toInt + 1
269
270  s3_out                 := DontCare
271  s3_out.uop             := s3_in.uop
272  s3_out.data            := DontCare
273  s3_out.redirectValid   := false.B
274  s3_out.redirect        := DontCare
275  s3_out.debug.isMMIO    := s3_in.mmio
276  s3_out.debug.paddr     := s3_in.paddr
277  s3_out.debug.vaddr     := s3_in.vaddr
278  s3_out.debug.isPerfCnt := false.B
279  s3_out.fflags          := DontCare
280
281  // Pipeline
282  // --------------------------------------------------------------------------------
283  // stage x
284  // --------------------------------------------------------------------------------
285  // delay TotalSelectCycles - 2 cycle(s)
286  val TotalDelayCycles = TotalSelectCycles - 2
287  val sx_valid = Wire(Vec(TotalDelayCycles + 1, Bool()))
288  val sx_ready = Wire(Vec(TotalDelayCycles + 1, Bool()))
289  val sx_in    = Wire(Vec(TotalDelayCycles + 1, new ExuOutput))
290
291  // backward ready signal
292  s3_ready := sx_ready.head
293  for (i <- 0 until TotalDelayCycles + 1) {
294    if (i == 0) {
295      sx_valid(i) := s3_valid
296      sx_in(i)    := s3_out
297      sx_ready(i) := !s3_valid(i) || sx_in(i).uop.robIdx.needFlush(io.redirect) || (if (TotalDelayCycles == 0) io.stout.ready else sx_ready(i+1))
298    } else {
299      val cur_kill   = sx_in(i).uop.robIdx.needFlush(io.redirect)
300      val cur_can_go = (if (i == TotalDelayCycles) io.stout.ready else sx_ready(i+1))
301      val cur_fire   = sx_valid(i) && !cur_kill && cur_can_go
302      val prev_fire  = sx_valid(i-1) && !sx_in(i-1).uop.robIdx.needFlush(io.redirect) && sx_ready(i)
303
304      sx_ready(i) := !sx_valid(i) || cur_kill || (if (i == TotalDelayCycles) io.stout.ready else sx_ready(i+1))
305      val sx_valid_can_go = prev_fire || cur_fire || cur_kill
306      sx_valid(i) := RegEnable(Mux(prev_fire, true.B, false.B), sx_valid_can_go)
307      sx_in(i) := RegEnable(sx_in(i-1), prev_fire)
308    }
309  }
310  val sx_last_valid = sx_valid.takeRight(1).head
311  val sx_last_ready = sx_ready.takeRight(1).head
312  val sx_last_in    = sx_in.takeRight(1).head
313  sx_last_ready := !sx_last_valid || sx_last_in.uop.robIdx.needFlush(io.redirect) || io.stout.ready
314
315  io.stout.valid := sx_last_valid && !sx_last_in.uop.robIdx.needFlush(io.redirect)
316  io.stout.bits := sx_last_in
317
318  io.debug_ls := DontCare
319  io.debug_ls.s1.isTlbFirstMiss := io.tlb.resp.valid && io.tlb.resp.bits.miss && io.tlb.resp.bits.debug.isFirstIssue
320  io.debug_ls.s1_robIdx := s1_in.uop.robIdx.value
321
322  private def printPipeLine(pipeline: LsPipelineBundle, cond: Bool, name: String): Unit = {
323    XSDebug(cond,
324      p"$name" + p" pc ${Hexadecimal(pipeline.uop.cf.pc)} " +
325        p"addr ${Hexadecimal(pipeline.vaddr)} -> ${Hexadecimal(pipeline.paddr)} " +
326        p"op ${Binary(pipeline.uop.ctrl.fuOpType)} " +
327        p"data ${Hexadecimal(pipeline.data)} " +
328        p"mask ${Hexadecimal(pipeline.mask)}\n"
329    )
330  }
331
332  printPipeLine(s0_out, s0_valid, "S0")
333  printPipeLine(s1_out, s1_valid, "S1")
334
335  // perf cnt
336  XSPerfAccumulate("s0_in_valid",                s0_valid)
337  XSPerfAccumulate("s0_in_fire",                 s0_fire)
338  XSPerfAccumulate("s0_in_fire_first_issue",     s0_fire && s0_isFirstIssue)
339  XSPerfAccumulate("s0_addr_spec_success",       s0_fire && s0_saddr(VAddrBits-1, 12) === s0_in.src(0)(VAddrBits-1, 12))
340  XSPerfAccumulate("s0_addr_spec_failed",        s0_fire && s0_saddr(VAddrBits-1, 12) =/= s0_in.src(0)(VAddrBits-1, 12))
341  XSPerfAccumulate("s0_addr_spec_success_once",  s0_fire && s0_saddr(VAddrBits-1, 12) === s0_in.src(0)(VAddrBits-1, 12) && s0_isFirstIssue)
342  XSPerfAccumulate("s0_addr_spec_failed_once",   s0_fire && s0_saddr(VAddrBits-1, 12) =/= s0_in.src(0)(VAddrBits-1, 12) && s0_isFirstIssue)
343
344  XSPerfAccumulate("s1_in_valid",                s1_valid)
345  XSPerfAccumulate("s1_in_fire",                 s1_fire)
346  XSPerfAccumulate("s1_in_fire_first_issue",     s1_fire && s1_in.isFirstIssue)
347  XSPerfAccumulate("s1_tlb_miss",                s1_fire && s1_tlb_miss)
348  XSPerfAccumulate("s1_tlb_miss_first_issue",    s1_fire && s1_tlb_miss && s1_in.isFirstIssue)
349  // end
350}