From 9ff4594d26f485495f47d4473905af9c4f10caa8 Mon Sep 17 00:00:00 2001
From: Tim Newsome <tim@sifive.com>
Date: Tue, 20 Jun 2017 15:02:28 -0700
Subject: [PATCH] Smoketest multicore.

When connecting to gdb, select a random thread and use that for the
current test.

Also replace infinite_loop with something that will later allow
smoketesting of more than one thread.
---
 debug/programs/infinite_loop.S | 40 ++++++++++++++++++++++++++++++++++
 debug/programs/infinite_loop.c |  9 --------
 debug/testlib.py               | 20 ++++++++++++-----
 3 files changed, 55 insertions(+), 14 deletions(-)
 create mode 100644 debug/programs/infinite_loop.S
 delete mode 100644 debug/programs/infinite_loop.c

diff --git a/debug/programs/infinite_loop.S b/debug/programs/infinite_loop.S
new file mode 100644
index 0000000..4b83143
--- /dev/null
+++ b/debug/programs/infinite_loop.S
@@ -0,0 +1,40 @@
+#include "encoding.h"
+
+        .global main
+
+        // Load constants into all registers so we can test no register are
+        // clobbered after attaching.
+main:
+        csrr    x1, CSR_MISA
+        slli    x2, x1, 1
+        slli    x3, x2, 1
+        slli    x4, x3, 1
+        slli    x5, x4, 1
+        slli    x6, x5, 1
+        slli    x7, x6, 1
+        slli    x8, x7, 1
+        slli    x9, x8, 1
+        slli    x10, x9, 1
+        slli    x11, x10, 1
+        slli    x12, x11, 1
+        slli    x13, x12, 1
+        slli    x14, x13, 1
+        slli    x15, x14, 1
+        slli    x16, x15, 1
+        slli    x17, x16, 1
+        slli    x18, x17, 1
+        slli    x19, x18, 1
+        slli    x20, x19, 1
+        slli    x21, x20, 1
+        slli    x22, x21, 1
+        slli    x23, x22, 1
+        slli    x24, x23, 1
+        slli    x25, x24, 1
+        slli    x26, x25, 1
+        slli    x27, x26, 1
+        slli    x28, x27, 1
+        slli    x29, x28, 1
+        slli    x30, x29, 1
+        slli    x31, x30, 1
+1:
+        j       1b
diff --git a/debug/programs/infinite_loop.c b/debug/programs/infinite_loop.c
deleted file mode 100644
index 350d1de..0000000
--- a/debug/programs/infinite_loop.c
+++ /dev/null
@@ -1,9 +0,0 @@
-volatile int forever = 1;
-
-int main()
-{
-    while (forever)
-        ;
-
-    return 1;
-}
diff --git a/debug/testlib.py b/debug/testlib.py
index 30c31c5..b8ff5c2 100644
--- a/debug/testlib.py
+++ b/debug/testlib.py
@@ -1,4 +1,5 @@
 import os.path
+import random
 import re
 import shlex
 import subprocess
@@ -82,7 +83,7 @@ class Spike(object):
             os.environ['REMOTE_BITBANG_HOST'] = 'localhost'
         self.infinite_loop = target.compile(
                 "programs/checksum.c", "programs/tiny-malloc.c",
-                "programs/infinite_loop.c", "-DDEFINE_MALLOC", "-DDEFINE_FREE")
+                "programs/infinite_loop.S", "-DDEFINE_MALLOC", "-DDEFINE_FREE")
         cmd.append(self.infinite_loop)
         logfile = open(self.logname, "w")
         logfile.write("+ %s\n" % " ".join(cmd))
@@ -219,7 +220,12 @@ class Openocd(object):
                 raise Exception("ERROR: Timed out waiting for OpenOCD to "
                         "examine RISCV core")
 
-        self.port = self._get_gdb_server_port()
+        try:
+            self.port = self._get_gdb_server_port()
+        except:
+            header("OpenOCD log")
+            sys.stdout.write(log)
+            raise
 
     def _get_gdb_server_port(self):
         """Get port that OpenOCD's gdb server is listening on."""
@@ -586,9 +592,13 @@ class GdbTest(BaseTest):
         if self.server.port:
             self.gdb.command(
                     "target extended-remote localhost:%d" % self.server.port)
-            # Force gdb to discover threads now, otherwise it might interrupt
-            # us at some point when it decides by itself to check.
-            self.gdb.command("info threads")
+            # Select a random thread.
+            # TODO: Allow a command line option to force a specific thread.
+            output = self.gdb.command("info threads")
+            threads = re.findall(r"Thread (\d+)", output)
+            if threads:
+                thread = random.choice(threads)
+                self.gdb.command("thread %s" % thread)
 
         # FIXME: OpenOCD doesn't handle PRIV now
         #self.gdb.p("$priv=3")
-- 
2.30.2