From 4215f480ef5178816530fffd3226a667e6012318 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <andrew@sifive.com>
Date: Mon, 27 Mar 2017 22:06:52 -0700
Subject: [PATCH] Write instruction to badaddr on illegal instruction traps

---
 src/main/scala/rocket/CSR.scala    |  5 ++---
 src/main/scala/rocket/Rocket.scala | 19 +++++++++++++++----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/main/scala/rocket/CSR.scala b/src/main/scala/rocket/CSR.scala
index 5ff0626a..46671a82 100644
--- a/src/main/scala/rocket/CSR.scala
+++ b/src/main/scala/rocket/CSR.scala
@@ -498,11 +498,10 @@ class CSRFile(perfEventSets: EventSets = new EventSets(Seq()))(implicit p: Param
   when (exception) {
     val epc = ~(~io.pc | (coreInstBytes-1))
 
-    val write_badaddr = cause isOneOf (Causes.breakpoint,
+    val write_badaddr = cause isOneOf (Causes.illegal_instruction, Causes.breakpoint,
       Causes.misaligned_load, Causes.misaligned_store, Causes.misaligned_fetch,
       Causes.load_access, Causes.store_access, Causes.fetch_access,
-      Causes.load_page_fault, Causes.store_page_fault, Causes.fetch_page_fault
-      )
+      Causes.load_page_fault, Causes.store_page_fault, Causes.fetch_page_fault)
 
     when (trapToDebug) {
       reg_debug := true
diff --git a/src/main/scala/rocket/Rocket.scala b/src/main/scala/rocket/Rocket.scala
index b3bc820c..22552498 100644
--- a/src/main/scala/rocket/Rocket.scala
+++ b/src/main/scala/rocket/Rocket.scala
@@ -297,9 +297,14 @@ class Rocket(implicit p: Parameters) extends CoreModule()(p)
     when (id_xcpt) { // pass PC down ALU writeback pipeline for badaddr
       ex_ctrl.alu_fn := ALU.FN_ADD
       ex_ctrl.alu_dw := DW_XPR
-      ex_ctrl.sel_alu1 := A1_PC
+      ex_ctrl.sel_alu1 := A1_RS1 // badaddr := instruction
       ex_ctrl.sel_alu2 := A2_ZERO
-      when (!bpu.io.xcpt_if && !ibuf.io.inst(0).bits.pf0 && ibuf.io.inst(0).bits.pf1) { // PC+2
+      when (bpu.io.xcpt_if || id_xcpt_pf || id_xcpt_ae) { // badaddr := PC
+        ex_ctrl.sel_alu1 := A1_PC
+      }
+      val pf_second = !ibuf.io.inst(0).bits.pf0 && ibuf.io.inst(0).bits.pf1
+      val ae_second = !ibuf.io.inst(0).bits.ae0 && ibuf.io.inst(0).bits.ae1
+      when (!bpu.io.xcpt_if && (pf_second || (!id_xcpt_pf && ae_second))) { // badaddr := PC+2
         ex_ctrl.sel_alu2 := A2_SIZE
         ex_reg_rvc := true
       }
@@ -316,10 +321,16 @@ class Rocket(implicit p: Parameters) extends CoreModule()(p)
       ex_reg_rs_bypass(i) := do_bypass
       ex_reg_rs_lsb(i) := bypass_src
       when (id_ren(i) && !do_bypass) {
-        ex_reg_rs_lsb(i) := id_rs(i)(bypass_src.getWidth-1,0)
-        ex_reg_rs_msb(i) := id_rs(i) >> bypass_src.getWidth
+        ex_reg_rs_lsb(i) := id_rs(i)(log2Ceil(bypass_sources.size)-1, 0)
+        ex_reg_rs_msb(i) := id_rs(i) >> log2Ceil(bypass_sources.size)
       }
     }
+    when (id_illegal_insn) {
+      val inst = Mux(ibuf.io.inst(0).bits.rvc, ibuf.io.inst(0).bits.raw(15, 0), ibuf.io.inst(0).bits.raw)
+      ex_reg_rs_bypass(0) := false
+      ex_reg_rs_lsb(0) := inst(log2Ceil(bypass_sources.size)-1, 0)
+      ex_reg_rs_msb(0) := inst >> log2Ceil(bypass_sources.size)
+    }
   }
   when (!ctrl_killd || csr.io.interrupt || ibuf.io.inst(0).bits.replay) {
     ex_reg_cause := id_cause