X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=debug%2Fgdbserver.py;h=de8241ce33fb6c503308971090b8929f5369b8f2;hb=03c18639caa0c26bb58e81d20cc05175011b313e;hp=61d4330bd7aecd9f0eddf086eefcc253016089de;hpb=dbc23e8c09b5bf5c34e11d00332552cdf8288a0b;p=riscv-tests.git

diff --git a/debug/gdbserver.py b/debug/gdbserver.py
index 61d4330..de8241c 100755
--- a/debug/gdbserver.py
+++ b/debug/gdbserver.py
@@ -1,26 +1,137 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 
 import os
 import sys
 import argparse
-import testlib
 import unittest
 import tempfile
 import time
 import random
 import binascii
 
+import .testlib
+
+
+MSTATUS_UIE = 0x00000001
+MSTATUS_SIE = 0x00000002
+MSTATUS_HIE = 0x00000004
+MSTATUS_MIE = 0x00000008
+MSTATUS_UPIE = 0x00000010
+MSTATUS_SPIE = 0x00000020
+MSTATUS_HPIE = 0x00000040
+MSTATUS_MPIE = 0x00000080
+MSTATUS_SPP = 0x00000100
+MSTATUS_HPP = 0x00000600
+MSTATUS_MPP = 0x00001800
+MSTATUS_FS = 0x00006000
+MSTATUS_XS = 0x00018000
+MSTATUS_MPRV = 0x00020000
+MSTATUS_PUM = 0x00040000
+MSTATUS_MXR = 0x00080000
+MSTATUS_VM = 0x1F000000
+MSTATUS32_SD = 0x80000000
+MSTATUS64_SD = 0x8000000000000000
+
+def gdb(
+        target=None,
+        port=None,
+        binary=None
+        ):
+
+    gdb = None
+    if parsed.gdb:
+        gdb = testlib.Gdb(parsed.gdb)
+    else:
+        gdb = testlib.Gdb()
+
+    if binary:
+        gdb.command("file %s" % binary)
+    if target:
+        gdb.command("set arch riscv:rv%d" % target.xlen)
+        gdb.command("set remotetimeout %d" % target.timeout_sec)
+    if port:
+        gdb.command("target extended-remote localhost:%d" % port)
+
+    return gdb
+
+        
+def ihex_line(address, record_type, data):
+    assert len(data) < 128
+    line = ":%02X%04X%02X" % (len(data), address, record_type)
+    check = len(data)
+    check += address % 256
+    check += address >> 8
+    check += record_type
+    for char in data:
+        value = ord(char)
+        check += value
+        line += "%02X" % value
+    line += "%02X\n" % ((256-check)%256)
+    return line
+
+def ihex_parse(line):
+    assert line.startswith(":")
+    line = line[1:]
+    data_len = int(line[:2], 16)
+    address = int(line[2:6], 16)
+    record_type = int(line[6:8], 16)
+    data = ""
+    for i in range(data_len):
+        data += "%c" % int(line[8+2*i:10+2*i], 16)
+    return record_type, address, data
+
+def readable_binary_string(s):
+    return "".join("%02x" % ord(c) for c in s)
+
 class DeleteServer(unittest.TestCase):
     def tearDown(self):
         del self.server
 
-class MemoryTest(DeleteServer):
+class SimpleRegisterTest(DeleteServer):
     def setUp(self):
         self.server = target.server()
-        self.gdb = testlib.Gdb()
-        self.gdb.command("target extended-remote localhost:%d" % self.server.port)
+        self.gdb = gdb(target, self.server.port)
+
+        # 0x13 is nop
+        self.gdb.command("p *((int*) 0x%x)=0x13" % target.ram)
+        self.gdb.command("p *((int*) 0x%x)=0x13" % (target.ram + 4))
+        self.gdb.command("p *((int*) 0x%x)=0x13" % (target.ram + 8))
+        self.gdb.p("$pc=0x%x" % target.ram)
+
+    def check_reg(self, name):
+        a = random.randrange(1<<target.xlen)
+        b = random.randrange(1<<target.xlen)
+        self.gdb.p("$%s=0x%x" % (name, a))
+        self.gdb.stepi()
+        self.assertEqual(self.gdb.p("$%s" % name), a)
+        self.gdb.p("$%s=0x%x" % (name, b))
+        self.gdb.stepi()
+        self.assertEqual(self.gdb.p("$%s" % name), b)
+
+    def test_s0(self):
+        # S0 is saved/restored in DSCRATCH
+        self.check_reg("s0")
+
+    def test_s1(self):
+        # S1 is saved/restored in Debug RAM
+        self.check_reg("s1")
+
+    def test_t0(self):
+        # T0 is not saved/restored at all
+        self.check_reg("t2")
+
+    def test_t2(self):
+        # T2 is not saved/restored at all
+        self.check_reg("t2")
+
+class SimpleMemoryTest(DeleteServer):
+    def setUp(self):
+        self.server = target.server()
+        self.gdb = gdb(target, self.server.port)
 
     def access_test(self, size, data_type):
+        self.assertEqual(self.gdb.p("sizeof(%s)" % data_type),
+                size)
         a = 0x86753095555aaaa & ((1<<(size*8))-1)
         b = 0xdeadbeef12345678 & ((1<<(size*8))-1)
         self.gdb.p("*((%s*)0x%x) = 0x%x" % (data_type, target.ram, a))
@@ -35,23 +146,51 @@ class MemoryTest(DeleteServer):
         self.access_test(2, 'short')
 
     def test_32(self):
-        self.access_test(4, 'long')
+        self.access_test(4, 'int')
 
     def test_64(self):
         self.access_test(8, 'long long')
 
+    def test_block(self):
+        length = 1024
+        line_length = 16
+        a = tempfile.NamedTemporaryFile(suffix=".ihex")
+        data = ""
+        for i in range(length / line_length):
+            line_data = "".join(["%c" % random.randrange(256) for _ in range(line_length)])
+            data += line_data
+            a.write(ihex_line(i * line_length, 0, line_data))
+        a.flush()
+
+        self.gdb.command("restore %s 0x%x" % (a.name, target.ram))
+        for offset in range(0, length, 19*4) + [length-4]:
+            value = self.gdb.p("*((int*)0x%x)" % (target.ram + offset))
+            written = ord(data[offset]) | \
+                    (ord(data[offset+1]) << 8) | \
+                    (ord(data[offset+2]) << 16) | \
+                    (ord(data[offset+3]) << 24)
+            self.assertEqual(value, written)
+
+        b = tempfile.NamedTemporaryFile(suffix=".ihex")
+        self.gdb.command("dump ihex memory %s 0x%x 0x%x" % (b.name, target.ram,
+            target.ram + length))
+        for line in b:
+            record_type, address, line_data = ihex_parse(line)
+            if (record_type == 0):
+                self.assertEqual(readable_binary_string(line_data),
+                        readable_binary_string(data[address:address+len(line_data)]))
+
 class InstantHaltTest(DeleteServer):
     def setUp(self):
         self.server = target.server()
-        self.gdb = testlib.Gdb()
-        self.gdb.command("target extended-remote localhost:%d" % self.server.port)
-
+        self.gdb = gdb(target, self.server.port)
+         
     def test_instant_halt(self):
-        self.assertEqual(0x1000, self.gdb.p("$pc"))
-        # For some reason instret resets to 0.
-        self.assertLess(self.gdb.p("$instret"), 8)
-        self.gdb.command("stepi")
-        self.assertNotEqual(0x1000, self.gdb.p("$pc"))
+        self.assertEqual(target.reset_vector, self.gdb.p("$pc"))
+        # mcycle and minstret have no defined reset value.
+        mstatus = self.gdb.p("$mstatus")
+        self.assertEqual(mstatus & (MSTATUS_MIE | MSTATUS_MPRV |
+            MSTATUS_VM), 0)
 
     def test_change_pc(self):
         """Change the PC right as we come out of reset."""
@@ -60,48 +199,123 @@ class InstantHaltTest(DeleteServer):
         self.gdb.command("p *((int*) 0x%x)=0x13" % (target.ram + 4))
         self.gdb.command("p *((int*) 0x%x)=0x13" % (target.ram + 8))
         self.gdb.p("$pc=0x%x" % target.ram)
-        self.gdb.command("stepi")
-        self.assertEqual((target.ram + 4), self.gdb.p("$pc"))
-        self.gdb.command("stepi")
+        self.gdb.stepi()
         self.assertEqual((target.ram + 4), self.gdb.p("$pc"))
+        self.gdb.stepi()
+        self.assertEqual((target.ram + 8), self.gdb.p("$pc"))
 
 class DebugTest(DeleteServer):
     def setUp(self):
-        self.binary = target.compile("programs/debug.c", "programs/checksum.c")
+        # Include malloc so that gdb can make function calls. I suspect this
+        # malloc will silently blow through the memory set aside for it, so be
+        # careful.
+        self.binary = target.compile("programs/debug.c", "programs/checksum.c",
+                "programs/tiny-malloc.c", "-DDEFINE_MALLOC", "-DDEFINE_FREE")
         self.server = target.server()
-        self.gdb = testlib.Gdb()
-        self.gdb.command("file %s" % self.binary)
-        self.gdb.command("target extended-remote localhost:%d" % self.server.port)
+        self.gdb = gdb(target, self.server.port, self.binary)
         self.gdb.load()
         self.gdb.b("_exit")
 
-    def exit(self):
+    def exit(self, expected_result = 0xc86455d4):
         output = self.gdb.c()
         self.assertIn("Breakpoint", output)
         self.assertIn("_exit", output)
-        self.assertEqual(self.gdb.p("status"), 0xc86455d4)
+        self.assertEqual(self.gdb.p("status"), expected_result)
+
+    def test_function_call(self):
+        self.gdb.b("main:start")
+        self.gdb.c()
+        self.assertEqual(self.gdb.p('fib(6)'), 8)
+        self.assertEqual(self.gdb.p('fib(7)'), 13)
+        self.exit()
+
+    def test_change_string(self):
+        text = "This little piggy went to the market."
+        self.gdb.b("main:start")
+        self.gdb.c()
+        self.gdb.p('fox = "%s"' % text)
+        self.exit(0x43b497b8)
 
     def test_turbostep(self):
         """Single step a bunch of times."""
+        self.gdb.b("main:start")
+        self.gdb.c()
         self.gdb.command("p i=0");
         last_pc = None
+        advances = 0
+        jumps = 0
         for _ in range(100):
-            self.gdb.command("stepi")
-            pc = self.gdb.command("p $pc")
+            self.gdb.stepi()
+            pc = self.gdb.p("$pc")
             self.assertNotEqual(last_pc, pc)
+            if (last_pc and pc > last_pc and pc - last_pc <= 4):
+                advances += 1
+            else:
+                jumps += 1
             last_pc = pc
+        # Some basic sanity that we're not running between breakpoints or
+        # something.
+        self.assertGreater(jumps, 10)
+        self.assertGreater(advances, 50)
 
     def test_exit(self):
         self.exit()
 
+    def test_symbols(self):
+        self.gdb.b("main")
+        self.gdb.b("rot13")
+        output = self.gdb.c()
+        self.assertIn(", main ", output)
+        output = self.gdb.c()
+        self.assertIn(", rot13 ", output)
+
     def test_breakpoint(self):
         self.gdb.b("rot13")
         # The breakpoint should be hit exactly 2 times.
         for i in range(2):
             output = self.gdb.c()
+            self.gdb.p("$pc")
+            self.assertIn("Breakpoint ", output)
+            #TODO self.assertIn("rot13 ", output)
+        self.exit()
+
+    def test_hwbp_1(self):
+        if target.instruction_hardware_breakpoint_count < 1:
+            return
+
+        self.gdb.hbreak("rot13")
+        # The breakpoint should be hit exactly 2 times.
+        for i in range(2):
+            output = self.gdb.c()
+            self.gdb.p("$pc")
             self.assertIn("Breakpoint ", output)
+            #TODO self.assertIn("rot13 ", output)
         self.exit()
 
+    def test_hwbp_2(self):
+        if target.instruction_hardware_breakpoint_count < 2:
+            return
+
+        self.gdb.hbreak("main")
+        self.gdb.hbreak("rot13")
+        # We should hit 3 breakpoints.
+        for i in range(3):
+            output = self.gdb.c()
+            self.gdb.p("$pc")
+            self.assertIn("Breakpoint ", output)
+            #TODO self.assertIn("rot13 ", output)
+        self.exit()
+
+    def test_too_many_hwbp(self):
+        for i in range(30):
+            self.gdb.hbreak("*rot13 + %d" % (i * 4))
+
+        output = self.gdb.c()
+        self.assertIn("Cannot insert hardware breakpoint", output)
+        # Clean up, otherwise the hardware breakpoints stay set and future
+        # tests may fail.
+        self.gdb.command("D")
+
     def test_registers(self):
         # Get to a point in the code where some registers have actually been
         # used.
@@ -129,7 +343,7 @@ class DebugTest(DeleteServer):
         #    instret = self.gdb.p("$instret")
         #    self.assertNotEqual(instret, last_instret)
         #    last_instret = instret
-        #    self.gdb.command("stepi")
+        #    self.gdb.stepi()
 
         self.exit()
 
@@ -137,39 +351,48 @@ class DebugTest(DeleteServer):
         """Sending gdb ^C while the program is running should cause it to halt."""
         self.gdb.b("main:start")
         self.gdb.c()
-        self.gdb.command("p i=123");
+        self.gdb.p("i=123");
         self.gdb.c(wait=False)
         time.sleep(0.1)
         output = self.gdb.interrupt()
-        assert "main" in output
+        #TODO: assert "main" in output
         self.assertGreater(self.gdb.p("j"), 10)
         self.gdb.p("i=0");
         self.exit()
 
+class StepTest(DeleteServer):
+    def setUp(self):
+        self.binary = target.compile("programs/step.S")
+        self.server = target.server()
+        self.gdb = gdb(target, self.server.port, self.binary)
+        self.gdb.load()
+        self.gdb.b("main")
+        self.gdb.c()
+
+    def test_step(self):
+        main = self.gdb.p("$pc")
+        for expected in (4, 8, 0xc, 0x10, 0x18, 0x1c, 0x28, 0x20, 0x2c, 0x2c):
+            self.gdb.stepi()
+            pc = self.gdb.p("$pc")
+            self.assertEqual("%x" % pc, "%x" % (expected + main))
+
 class RegsTest(DeleteServer):
     def setUp(self):
         self.binary = target.compile("programs/regs.S")
         self.server = target.server()
-        self.gdb = testlib.Gdb()
-        self.gdb.command("file %s" % self.binary)
-        self.gdb.command("target extended-remote localhost:%d" % self.server.port)
-        self.gdb.command("load")
+        self.gdb = gdb(target, self.server.port, self.binary)
+        self.gdb.load()
         self.gdb.b("main")
         self.gdb.b("handle_trap")
         self.gdb.c()
 
     def test_write_gprs(self):
-        # Note a0 is missing from this list since it's used to hold the
-        # address.
-        regs = ("ra", "sp", "gp", "tp", "t0", "t1", "t2", "fp", "s1",
-                "a1", "a2", "a3", "a4", "a5", "a6", "a7", "s2", "s3", "s4",
-                "s5", "s6", "s7", "s8", "s9", "s10", "s11", "t3", "t4", "t5",
-                "t6")
+        regs = [("x%d" % n) for n in range(2, 32)]
 
         self.gdb.p("$pc=write_regs")
         for i, r in enumerate(regs):
-            self.gdb.command("p $%s=%d" % (r, (0xdeadbeef<<i)+17))
-        self.gdb.command("p $a0=data")
+            self.gdb.p("$%s=%d" % (r, (0xdeadbeef<<i)+17))
+        self.gdb.p("$x1=data")
         self.gdb.command("b all_done")
         output = self.gdb.c()
         self.assertIn("Breakpoint ", output)
@@ -179,7 +402,7 @@ class RegsTest(DeleteServer):
         self.gdb.command("info registers")
         for n in range(len(regs)):
             self.assertEqual(self.gdb.x("data+%d" % (8*n), 'g'),
-                    (0xdeadbeef<<n)+17)
+                    ((0xdeadbeef<<n)+17) & ((1<<target.xlen)-1))
 
     def test_write_csrs(self):
         # As much a test of gdb as of the simulator.
@@ -201,34 +424,32 @@ class RegsTest(DeleteServer):
 
 class DownloadTest(DeleteServer):
     def setUp(self):
-        length = 2**20
-        fd = file("download.c", "w")
-        fd.write("#include <stdint.h>\n")
-        fd.write("unsigned int crc32a(uint8_t *message, unsigned int size);\n")
-        fd.write("uint32_t length = %d;\n" % length)
-        fd.write("uint8_t d[%d] = {\n" % length)
+        length = min(2**20, target.ram_size - 2048)
+        download_c = tempfile.NamedTemporaryFile(prefix="download_", suffix=".c")
+        download_c.write("#include <stdint.h>\n")
+        download_c.write("unsigned int crc32a(uint8_t *message, unsigned int size);\n")
+        download_c.write("uint32_t length = %d;\n" % length)
+        download_c.write("uint8_t d[%d] = {\n" % length)
         self.crc = 0
         for i in range(length / 16):
-            fd.write("  /* 0x%04x */ " % (i * 16));
+            download_c.write("  /* 0x%04x */ " % (i * 16));
             for _ in range(16):
                 value = random.randrange(1<<8)
-                fd.write("%d, " % value)
+                download_c.write("%d, " % value)
                 self.crc = binascii.crc32("%c" % value, self.crc)
-            fd.write("\n");
-        fd.write("};\n");
-        fd.write("uint8_t *data = &d[0];\n");
-        fd.write("uint32_t main() { return crc32a(data, length); }\n")
-        fd.close()
+            download_c.write("\n");
+        download_c.write("};\n");
+        download_c.write("uint8_t *data = &d[0];\n");
+        download_c.write("uint32_t main() { return crc32a(data, length); }\n")
+        download_c.flush()
 
         if self.crc < 0:
             self.crc += 2**32
 
-        self.binary = target.compile("download.c", "programs/checksum.c")
+        self.binary = target.compile(download_c.name, "programs/checksum.c")
         self.server = target.server()
-        self.gdb = testlib.Gdb()
-        self.gdb.command("file %s" % self.binary)
-        self.gdb.command("target extended-remote localhost:%d" % self.server.port)
-
+        self.gdb = gdb(target, self.server.port, self.binary)
+        
     def test_download(self):
         output = self.gdb.load()
         self.gdb.command("b _exit")
@@ -239,71 +460,220 @@ class MprvTest(DeleteServer):
     def setUp(self):
         self.binary = target.compile("programs/mprv.S")
         self.server = target.server()
-        self.gdb = testlib.Gdb()
-        self.gdb.command("file %s" % self.binary)
-        self.gdb.command("target extended-remote localhost:%d" % self.server.port)
+        self.gdb = gdb(target, self.server.port, self.binary)
         self.gdb.load()
 
     def test_mprv(self):
         """Test that the debugger can access memory when MPRV is set."""
         self.gdb.c(wait=False)
+        time.sleep(0.5)
         self.gdb.interrupt()
         output = self.gdb.command("p/x *(int*)(((char*)&data)-0x80000000)")
         self.assertIn("0xbead", output)
 
+class PrivTest(DeleteServer):
+    def setUp(self):
+        self.binary = target.compile("programs/priv.S")
+        self.server = target.server()
+        self.gdb = gdb(target, self.server.port, self.binary)
+        self.gdb.load()
+
+        misa = self.gdb.p("$misa")
+        self.supported = set()
+        if misa & (1<<20):
+            self.supported.add(0)
+        if misa & (1<<18):
+            self.supported.add(1)
+        if misa & (1<<7):
+            self.supported.add(2)
+        self.supported.add(3)
+
+    def test_rw(self):
+        """Test reading/writing priv."""
+        for privilege in range(4):
+            self.gdb.p("$priv=%d" % privilege)
+            self.gdb.stepi()
+            actual = self.gdb.p("$priv")
+            self.assertIn(actual, self.supported)
+            if privilege in self.supported:
+                self.assertEqual(actual, privilege)
+
+    def test_change(self):
+        """Test that the core's privilege level actually changes."""
+
+        if 0 not in self.supported:
+            # TODO: return not applicable
+            return
+
+        self.gdb.b("main")
+        self.gdb.c()
+
+        # Machine mode
+        self.gdb.p("$priv=3")
+        main = self.gdb.p("$pc")
+        self.gdb.stepi()
+        self.assertEqual("%x" % self.gdb.p("$pc"), "%x" % (main+4))
+
+        # User mode
+        self.gdb.p("$priv=0")
+        self.gdb.stepi()
+        # Should have taken an exception, so be nowhere near main.
+        pc = self.gdb.p("$pc")
+        self.assertTrue(pc < main or pc > main + 0x100)
+
 class Target(object):
+    directory = None
+    timeout_sec = 2
+    
     def server(self):
         raise NotImplementedError
 
     def compile(self, *sources):
-        return testlib.compile(sources +
+        binary_name = "%s_%s-%d" % (
+                self.name,
+                os.path.basename(os.path.splitext(sources[0])[0]),
+                self.xlen)
+        if parsed.isolate:
+            self.temporary_binary = tempfile.NamedTemporaryFile(
+                    prefix=binary_name + "_")
+            binary_name = self.temporary_binary.name
+        testlib.compile(sources +
                 ("programs/entry.S", "programs/init.c",
                     "-I", "../env",
-                    "-T", "targets/%s/link.lds" % self.name,
+                    "-T", "targets/%s/link.lds" % (self.directory or self.name),
                     "-nostartfiles",
-                    "-mcmodel=medany"), xlen=self.xlen)
+                    "-mcmodel=medany",
+                    "-o", binary_name),
+                xlen=self.xlen)
+        return binary_name
 
 class SpikeTarget(Target):
-    name = "spike"
-    xlen = 64
+    directory = "spike"
     ram = 0x80010000
+    ram_size = 5 * 1024 * 1024
+    instruction_hardware_breakpoint_count = 0
+    reset_vector = 0x1000
+
+class Spike64Target(SpikeTarget):
+    name = "spike64"
+    xlen = 64
 
     def server(self):
         return testlib.Spike(parsed.cmd, halted=True)
 
-class MicroSemiTarget(Target):
-    name = "m2gl_m2s"
+class Spike32Target(SpikeTarget):
+    name = "spike32"
+    xlen = 32
+
+    def server(self):
+        return testlib.Spike(parsed.cmd, halted=True, xlen=32)
+
+class FreedomE300Target(Target):
+    name = "freedom-e300"
+    xlen = 32
+    ram = 0x80000000
+    ram_size = 16 * 1024
+    instruction_hardware_breakpoint_count = 2
+
+    def server(self):
+        return testlib.Openocd(cmd=parsed.cmd,
+                config="targets/%s/openocd.cfg" % self.name)
+
+class FreedomE300SimTarget(Target):
+    name = "freedom-e300-sim"
     xlen = 32
+    timeout_sec = 240
+    ram = 0x80000000
+    ram_size = 256 * 1024 * 1024
+    instruction_hardware_breakpoint_count = 2
+       
+    def server(self):
+        sim = testlib.VcsSim(simv=parsed.run, debug=False)
+        openocd = testlib.Openocd(cmd=parsed.cmd,
+                            config="targets/%s/openocd.cfg" % self.name,
+                            otherProcess = sim)
+        time.sleep(20)
+        return openocd
+
+class FreedomU500Target(Target):
+    name = "freedom-u500"
+    xlen = 64
     ram = 0x80000000
+    ram_size = 16 * 1024
+    instruction_hardware_breakpoint_count = 2
 
     def server(self):
         return testlib.Openocd(cmd=parsed.cmd,
                 config="targets/%s/openocd.cfg" % self.name)
+    
+class FreedomU500SimTarget(Target):
+    name = "freedom-u500-sim"
+    xlen = 64
+    timeout_sec = 240
+    ram = 0x80000000
+    ram_size = 256 * 1024 * 1024
+    instruction_hardware_breakpoint_count = 2
+       
+    def server(self):
+        sim = testlib.VcsSim(simv=parsed.run, debug=False)
+        openocd = testlib.Openocd(cmd=parsed.cmd,
+                            config="targets/%s/openocd.cfg" % self.name,
+                            otherProcess = sim)
+        time.sleep(20)
+        return openocd
 
 targets = [
-        SpikeTarget,
-        MicroSemiTarget
-        ]
+        Spike32Target,
+        Spike64Target,
+        FreedomE300Target,
+        FreedomU500Target,
+        FreedomE300SimTarget,
+        FreedomU500SimTarget]
 
 def main():
-    parser = argparse.ArgumentParser()
+    parser = argparse.ArgumentParser(
+            epilog="""
+            Example command line from the real world:
+            Run all RegsTest cases against a physical FPGA, with custom openocd command:
+            ./gdbserver.py --freedom-e-300 --cmd "$HOME/SiFive/openocd/src/openocd -s $HOME/SiFive/openocd/tcl -d" -- -vf RegsTest
+            """)
     group = parser.add_mutually_exclusive_group(required=True)
     for t in targets:
         group.add_argument("--%s" % t.name, action="store_const", const=t,
                 dest="target")
+    parser.add_argument("--run",
+                        help="The command to use to start the actual target (e.g. simulation)")
     parser.add_argument("--cmd",
             help="The command to use to start the debug server.")
+    parser.add_argument("--gdb",
+            help="The command to use to start gdb.")
+
+    xlen_group = parser.add_mutually_exclusive_group()
+    xlen_group.add_argument("--32", action="store_const", const=32, dest="xlen",
+            help="Force the target to be 32-bit.")
+    xlen_group.add_argument("--64", action="store_const", const=64, dest="xlen",
+            help="Force the target to be 64-bit.")
+
+    parser.add_argument("--isolate", action="store_true",
+            help="Try to run in such a way that multiple instances can run at "
+            "the same time. This may make it harder to debug a failure if it "
+            "does occur.")
+
     parser.add_argument("unittest", nargs="*")
     global parsed
     parsed = parser.parse_args()
 
     global target
     target = parsed.target()
+
+    if parsed.xlen:
+        target.xlen = parsed.xlen
+
     unittest.main(argv=[sys.argv[0]] + parsed.unittest)
 
 # TROUBLESHOOTING TIPS
 # If a particular test fails, run just that one test, eg.:
-# ./tests/gdbserver.py MprvTest.test_mprv
+# ./gdbserver.py MprvTest.test_mprv
 # Then inspect gdb.log and spike.log to see what happened in more detail.
 
 if __name__ == '__main__':