Merge pull request #272 from davidharrishmc/dev

fdivsqrt coverage and fix bug of not trapping on access to odd-numbered pmpcfg

docs/testplans/testplan.md

@@ -1,6 +1,29 @@
-# CORE-V Wally Test Plan
+# CORE-V Wally Design Verification Test Plan
+
+CORE-V Wally is functionally tested in the following ways.  Each test is run in lock-step against ImperasDV to ensure all architectural state is correct after each instruction.
+
+| Functions      | Coverage Method | Status |
+| ----------- | ----------- |----|
+|  Instructions | riscv-arch-test | Pass   |
+| Privileged Unit   | wally-riscv-arch-test        | Pass   |
+| Virtual Memory | wally-riscv-arch-test | Pass |
+| PMP | wally-riscv-arch-test | Pass
+| Peripherals | wally-riscv-arch-test | Pass |
+| Floating-Point | TestFloat | Pass |
+| General | Code Coverage | 91% |
+| General | Boot Linux in Sim | Pass | 
+| General | Boot Linux on FPGA | Pass |
+
+
+The following performance validation is also run:
+| Function | Method | Status |
+| --- | --- | --- |
+| Overall Performance | embench | Pass|
+| Overall Performance | coremark | Pass |
+| Branch Predictor | *** | Pass |
+| Cache Miss Rate | *** | Pass |
+
 
-CORE-V Wally is tested in the following ways:
 
 * Run [RISC-V Architecture Compatibility Tests](https://github.com/riscv-non-isa/riscv-arch-test) in lock-step against the ImperasDV reference model.
 * Run custom tests to cover virtual memory, PMP, privileged unit, and peripherals in lock step against ImperasDV.

sim/coverage-exclusions-rv64gc.do

@@ -31,11 +31,14 @@
 do GetLineNum.do
 
 # LZA (i<64) statement confuses coverage tool 
-# This is ugly to exlcude the whole file - is there a better option?  // coverage off isn't working
+# DH 4/22/23: Exclude all LZAs
 coverage exclude -srcfile lzc.sv 
 
-# FDIVSQRT has 
+# DH 4/22/23: FDIVSQRT can't go directly from done to busy again
 coverage exclude -scope /dut/core/fpu/fpu/fdivsqrt/fdivsqrtfsm -ftrans state DONE->BUSY
+# DH 4/22/23: The busy->idle transition only occurs if a FlushE occurs while the divider is busy.  The flush is caused by a trap or return,
+# which won't happen while the divider is busy. 
+coverage exclude -scope /dut/core/fpu/fpu/fdivsqrt/fdivsqrtfsm -ftrans state BUSY->IDLE
 
 ### Exclude D$ states and logic for the I$ instance
 # This is cleaner than trying to set an I$-specific pragma in cachefsm.sv (which would exclude it for the D$ instance too)

src/cache/cachefsm.sv

@@ -159,7 +159,7 @@ module cachefsm #(parameter READ_ONLY_CACHE = 0) (
   assign SelFlush = (CurrState == STATE_READY & FlushCache) |
           (CurrState == STATE_FLUSH) | 
           (CurrState == STATE_FLUSH_WRITEBACK);
-  // coverage off -item e -fecexprrow 1
+  // coverage off -item e 1 -fecexprrow 1
   // (state is always FLUSH_WRITEBACK when FlushWayFlag & CacheBusAck)
   assign FlushAdrCntEn = (CurrState == STATE_FLUSH_WRITEBACK & FlushWayFlag & CacheBusAck) |
              (CurrState == STATE_FLUSH & FlushWayFlag & ~LineDirty);

src/fpu/fdivsqrt/fdivsqrtfsm.sv

@@ -66,7 +66,6 @@ module fdivsqrtfsm(
       if (reset | FlushE) begin
           state <= #1 IDLE; 
       end else if (IFDivStartE) begin // IFDivStartE implies stat is IDLE
-//       end else if ((state == IDLE) & IFDivStartE) begin // IFDivStartE implies stat is IDLE
           step <= CyclesE; 
           if (SpecialCaseE) state <= #1 DONE;
           else              state <= #1 BUSY;

src/privileged/csrm.sv

@@ -171,7 +171,8 @@ module csrm #(parameter
     IllegalCSRMAccessM = !(`S_SUPPORTED) & (CSRAdrM == MEDELEG | CSRAdrM == MIDELEG); // trap on DELEG register access when no S or N-mode
     if (CSRAdrM >= PMPADDR0 & CSRAdrM < PMPADDR0 + `PMP_ENTRIES) // reading a PMP entry
       CSRMReadValM = {{(`XLEN-(`PA_BITS-2)){1'b0}}, PMPADDR_ARRAY_REGW[CSRAdrM - PMPADDR0]};
-    else if (CSRAdrM >= PMPCFG0 & CSRAdrM < PMPCFG0 + `PMP_ENTRIES/4) begin
+    else if (CSRAdrM >= PMPCFG0 & CSRAdrM < PMPCFG0 + `PMP_ENTRIES/4 & (`XLEN==32 | CSRAdrM[0] == 0)) begin
+      // only odd-numbered PMPCFG entries exist in RV64
       if (`XLEN==64) begin
         entry = ({CSRAdrM[11:1], 1'b0} - PMPCFG0)*4; // disregard odd entries in RV64
         CSRMReadValM = {PMPCFG_ARRAY_REGW[entry+7],PMPCFG_ARRAY_REGW[entry+6],PMPCFG_ARRAY_REGW[entry+5],PMPCFG_ARRAY_REGW[entry+4],

tests/coverage/WALLY-init-lib.h

@@ -63,6 +63,9 @@ trap_handler:
     bgez t0, exception  # if msb is clear, it is an exception
 
 interrupt:              # must be a timer interrupt 
+    li t0, -1           # set mtimecmp to biggest number so it doesnt interrupt again
+    li t1, 0x02004000   # MTIMECMP in CLINT
+    sd t0, 0(t1)        
     j trap_return       # clean up and return
 
 exception:

tests/coverage/fpu.S

@@ -28,7 +28,7 @@
 
 main:
 
-    #bseti t0, zero, 14  # turn on FPU
+    bseti t0, zero, 14  # turn on FPU
     csrs mstatus, t0
 
     #Pull denormalized FP number from memory and pass it to fclass.S for coverage
@@ -105,6 +105,25 @@ main:
     # fcvt.w.q a0, ft0
     # fcvt.q.d ft3, ft0
 
+    // fdivsqrt: test busy->idle transition caused by a FlushE while divider is busy (when interrupt arrives)
+    // This code doesn't actually trigger a busy->idle transition because the pending timer interrupt doesn't occur until the division finishes.
+    li t0, 0x3F812345 # random value slightly bigger than 1
+    li t1, 0x3F823456
+    fmv.w.x ft0, t0  # move int to fp register
+    fmv.w.x ft1, t1
+    li t0, -1           # set mtimecmp to biggest number so it doesnt interrupt again
+    li t1, 0x02004000   # MTIMECMP in CLINT
+    sd t0, 0(t1)
+    csrsi mstatus, 0b1000   # enable interrupts with mstatus.MIE
+    li t1, 0x0200bff8   # read MTIME in CLINT
+    ld t0, 0(t1)        
+    addi t0, t0, 11
+    li t1, 0x02004000   # MTIMECMP in CLINT
+    sd t0, 0(t1)        # write mtime+10 to cause interrupt soon  This is very touchy timing and is sensitive to cache line fetch latency
+    nop
+    fdiv.s ft2, ft1, ft0 # should get interrupted, triggering a flush
+    csrci mstatus, 0b1000   # disable interrupts with mstatus.MIE
+
     # Completing branch coverage in fctrl.sv
     .word 0x38007553    // Testing the all False case for 119 - funct7 under, op = 101 0011
     .word 0x40000053    // Line 145 All False Test case - illegal instruction?
@@ -146,3 +165,4 @@ TestData2:
 .int 0xbf800000 #FP -1.0
 .int 0x7fa00000 #SNaN
 .int 0x3fffffff #OverFlow Test
+DivTestData: