Add liveness check

rvfi/checks/liveness_check.py

@@ -0,0 +1,46 @@
+from nmigen import *
+from nmigen.asserts import *
+
+"""
+Liveness Check
+"""
+
+class LivenessCheck(Elaboratable):
+    def __init__(self):
+        self.reset = Signal(1)
+        self.rvfi_order = Signal(64)
+        self.trig = Signal(1)
+        self.rvfi_valid = Signal(1)
+        self.rvfi_halt = Signal(1)
+        self.check = Signal(1)
+
+    def ports(self):
+        input_ports = [
+            self.reset,
+            self.rvfi_order,
+            self.trig,
+            self.rvfi_valid,
+            self.rvfi_halt,
+            self.check
+        ]
+        return input_ports
+
+    def elaborate(self, platform):
+        m = Module()
+
+        insn_order = AnyConst(64)
+        found_next_insn = Signal(1, reset=0)
+
+        with m.If(self.reset):
+            m.d.sync += found_next_insn.eq(0)
+        with m.Else():
+            with m.If(self.rvfi_valid & (self.rvfi_order == insn_order + 1)):
+                m.d.sync += found_next_insn.eq(1)
+            with m.If(self.trig):
+                m.d.comb += Assume(self.rvfi_valid)
+                m.d.comb += Assume(~self.rvfi_halt)
+                m.d.comb += Assume(insn_order == self.rvfi_order)
+            with m.If(self.check):
+                m.d.comb += Assert(found_next_insn)
+
+        return m

rvfi/cores/minerva/verify.py

@@ -4,6 +4,7 @@ from ...checks.pc_fwd_check import *
 from ...checks.pc_bwd_check import *
 from ...checks.reg_check import *
 from ...checks.causal_check import *
+from ...checks.liveness_check import *
 from minerva.core import *
 from ...insns.insn_lui import *
 from ...insns.insn_auipc import *
@@ -220,6 +221,26 @@ class CausalTestCase(FHDLTestCase):
     def verify(self):
         self.assertFormal(CausalSpec(), mode="bmc", depth=12, engine="smtbmc --nopresat")
 
+class LivenessSpec(Elaboratable):
+    def elaborate(self, platform):
+        m = Module()
+
+        m.submodules.cpu = cpu = Minerva(with_rvfi=True)
+        m.submodules.liveness_spec = liveness_spec = LivenessCheck()
+
+        m.d.comb += liveness_spec.reset.eq(0)
+        m.d.comb += liveness_spec.rvfi_valid.eq(cpu.rvfi.valid)
+        m.d.comb += liveness_spec.rvfi_order.eq(cpu.rvfi.order)
+        m.d.comb += liveness_spec.trig.eq(1)
+        m.d.comb += liveness_spec.rvfi_halt.eq(cpu.rvfi.halt)
+        m.d.comb += liveness_spec.check.eq(1)
+
+        return m
+
+class LivenessTestCase(FHDLTestCase):
+    def verify(self):
+        self.assertFormal(LivenessSpec(), mode="bmc", depth=12, engine="smtbmc --nopresat")
+
 print('*' * 80)
 print('*' + ' ' * 78 + '*')
 print('*                        Verifying the Minerva core ...                        *')
@@ -241,6 +262,9 @@ RegTestCase().verify()
 print("Verifying causal checks ...")
 CausalTestCase().verify()
 
+print("Verifying liveness checks ...")
+LivenessTestCase().verify()
+
 print('*' * 80)
 print('*' + ' ' * 78 + '*')
 print('*                      All verification tasks successful!                      *')