fix hrfid and mtmsrd so that it is identical to microwatt

[soc.git] / src / soc / fu / trap / main_stage.py

diff --git a/src/soc/fu/trap/main_stage.py b/src/soc/fu/trap/main_stage.py
index 116be81a79f38eb82b66eab540f0eb803f6f650e..1685f3f26db21075a89d65ca6adeddec89ae27d2 100644 (file)
--- a/src/soc/fu/trap/main_stage.py
+++ b/src/soc/fu/trap/main_stage.py
@@ -267,9 +267,13 @@ class TrapMainStage(PipeModBase):
                 # hypervisor stuff.  here: bits 3 (HV) and 51 (ME) were
                 # copied over by msr_copy but if HV was not set we need
                 # the *original* (msr_i) bits
-                with m.If(~msr_i[MSR.HV]):
-                    comb += msr_o.data[MSR.HV].eq(msr_i[MSR.HV])
-                    comb += msr_o.data[MSR.ME].eq(msr_i[MSR.ME])
+                # XXX taking this out to see what happens when running
+                # linux-5.7 microwatt buildroot.  microwatt does not
+                # implement HV, so this is unlikely to work.  0x900
+                # linux kernel exception handling tends to support this
+                # with m.If(~msr_i[MSR.HV]):
+                #     comb += msr_o.data[MSR.HV].eq(msr_i[MSR.HV])
+                #     comb += msr_o.data[MSR.ME].eq(msr_i[MSR.ME])
 
                 comb += msr_o.ok.eq(1)
 
@@ -297,11 +301,15 @@ class TrapMainStage(PipeModBase):
                 # MSR was in srr1: copy it over, however *caveats below*
                 comb += msr_copy(msr_o.data, srr1_i, zero_me=False) # don't zero
 
-                with m.If(~self.i.ctx.op.insn[9]): # XXX BAD HACK! (hrfid)
-                    with m.If(field(msr_i, 3)): # HV
-                        comb += field(msr_o, 51).eq(field(srr1_i, 51)) # ME
-                    with m.Else():
-                        comb += field(msr_o, 51).eq(field(msr_i, 51)) # ME
+                if False: # XXX no - not doing hypervisor yet
+                    with m.If(~self.i.ctx.op.insn[9]): # XXX BAD HACK! (hrfid)
+                        with m.If(field(msr_i, 3)): # HV
+                            comb += field(msr_o, 51).eq(field(srr1_i, 51)) # ME
+                        with m.Else():
+                            comb += field(msr_o, 51).eq(field(msr_i, 51)) # ME
+                else:
+                    # same as microwatt: treat MSR.ME rfid same as hrfid
+                    comb += field(msr_o, 51).eq(field(srr1_i, 51)) # ME
 
                 # check problem state: if set, not permitted to set EE,IR,DR
                 msr_check_pr(m, srr1_i, msr_o.data)