From ca937823c376c5c852a623470e9d5ea84fd4dcd6 Mon Sep 17 00:00:00 2001
From: Tim Newsome <tim@sifive.com>
Date: Wed, 8 Jun 2022 10:17:54 -0700
Subject: Add CeaseTest

To test OpenOCD behavior when one or more harts are powered down.
---
 debug/gdbserver.py     | 27 +++++++++++++++++++++++++++
 debug/programs/entry.S |  5 +++++
 debug/testlib.py       |  4 ++--
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/debug/gdbserver.py b/debug/gdbserver.py
index cc054a4..9da069c 100755
--- a/debug/gdbserver.py
+++ b/debug/gdbserver.py
@@ -1813,6 +1813,33 @@ class EbreakTest(GdbSingleHartTest):
         output = self.gdb.c()
         assertIn("_exit", output)
 
+class CeaseTest(ProgramTest):
+    """Test that we work correctly when a hart ceases to respond (e.g. because
+    it's powered down)."""
+
+    def early_applicable(self):
+        return len(self.target.harts) > 1
+
+    def setup(self):
+        ProgramTest.setup(self)
+        self.parkOtherHarts("cease")
+
+    def test(self):
+        self.gdb.b("main")
+        output = self.gdb.c()
+        assertIn("Breakpoint", output)
+        assertIn("main", output)
+
+        for hart in self.target.harts:
+            # Try to read the PC on the ceased harts
+            if hart != self.hart:
+                self.gdb.select_hart(hart)
+                self.gdb.p("$pc")
+
+        self.gdb.select_hart(self.hart)
+
+        self.exit()
+
 class FreeRtosTest(GdbTest):
     def early_applicable(self):
         return self.target.freertos_binary
diff --git a/debug/programs/entry.S b/debug/programs/entry.S
index 091efa4..84bebe2 100755
--- a/debug/programs/entry.S
+++ b/debug/programs/entry.S
@@ -204,6 +204,11 @@ trap_entry:
 loop_forever:
   j loop_forever
 
+  .align 2
+cease:
+  .word 0x30500073  // cease
+  j loop_forever
+
   // Fill the stack with data so we can see if it was overrun.
   .section .data
   .align 4
diff --git a/debug/testlib.py b/debug/testlib.py
index 6c185d4..65f0598 100644
--- a/debug/testlib.py
+++ b/debug/testlib.py
@@ -1231,13 +1231,13 @@ class GdbTest(BaseTest):
         del self.gdb
         BaseTest.classTeardown(self)
 
-    def parkOtherHarts(self):
+    def parkOtherHarts(self, symbol="loop_forever"):
         """Park harts besides the currently selected one in loop_forever()."""
         for hart in self.target.harts:
             # Park all harts that we're not using in a safe place.
             if hart != self.hart:
                 self.gdb.select_hart(hart)
-                self.gdb.p("$pc=loop_forever")
+                self.gdb.p("$pc=%s" % symbol)
 
         self.gdb.select_hart(self.hart)
 
-- 
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