Improve address translation tests (#261)

* Improve address translation tests.

Check that the mode we're testing is supported by hardware before
running the test.
Test with high address bits set, which catches a bug in OpenOCD.

* Turn off PMP for address translation test.

Otherwise it doesn't pass on HiFive Unleashed.

* Run TranslateTest on random hart.

Once riscv-collab/riscv-openocd#459 merges that will work.

debug/gdbserver.py

@@ -1229,15 +1229,7 @@ def setup(self):
             self.supported.add(2)
         self.supported.add(3)
 
-        # Disable physical memory protection by allowing U mode access to all
-        # memory.
-        try:
-            self.gdb.p("$pmpcfg0=0xf")  # TOR, R, W, X
-            self.gdb.p("$pmpaddr0=0x%x" %
-                    ((self.hart.ram + self.hart.ram_size) >> 2))
-        except testlib.CouldNotFetch:
-            # PMP registers are optional
-            pass
+        self.disable_pmp()
 
         # Ensure Virtual Memory is disabled if applicable (SATP register is not
         # reset)
@@ -1294,16 +1286,27 @@ class TranslateTest(GdbTest):
     compile_args = ("programs/translate.c", )
 
     def setup(self):
-        # TODO: If we use a random hart, then we get into trouble because
-        # gdb_read_memory_packet() ignores which hart is currently selected, so
-        # we end up reading satp from hart 0 when the address translation might
-        # be set up on hart 1 only.
-        self.gdb.select_hart(self.target.harts[0])
+        self.disable_pmp()
+
         self.gdb.load()
         self.gdb.b("main")
         output = self.gdb.c()
         assertRegex(output, r"\bmain\b")
 
+    def check_satp(self, mode):
+        if self.hart.xlen == 32:
+            satp = mode << 31
+        else:
+            satp = mode << 60
+        try:
+            self.gdb.p("$satp=0x%x" % satp)
+        except testlib.CouldNotFetch:
+            raise TestNotApplicable
+        readback = self.gdb.p("$satp")
+        self.gdb.p("$satp=0")
+        if readback != satp:
+            raise TestNotApplicable
+
     def test_translation(self):
         self.gdb.b("error")
         self.gdb.b("handle_trap")
@@ -1315,11 +1318,19 @@ def test_translation(self):
         assertEqual(0xdeadbeef, self.gdb.p("virtual[0]"))
         assertEqual(0x55667788, self.gdb.p("virtual[1]"))
 
+SATP_MODE_OFF = 0
+SATP_MODE_SV32 = 1
+SATP_MODE_SV39 = 8
+SATP_MODE_SV48 = 9
+SATP_MODE_SV57 = 10
+SATP_MODE_SV64 = 11
+
 class Sv32Test(TranslateTest):
     def early_applicable(self):
         return self.hart.xlen == 32
 
     def test(self):
+        self.check_satp(SATP_MODE_SV32)
         self.gdb.p("vms=&sv32")
         self.test_translation()
 
@@ -1328,6 +1339,7 @@ def early_applicable(self):
         return self.hart.xlen > 32
 
     def test(self):
+        self.check_satp(SATP_MODE_SV39)
         self.gdb.p("vms=&sv39")
         self.test_translation()
 
@@ -1336,6 +1348,7 @@ def early_applicable(self):
         return self.hart.xlen > 32
 
     def test(self):
+        self.check_satp(SATP_MODE_SV48)
         self.gdb.p("vms=&sv48")
         self.test_translation()
 

debug/programs/translate.c

@@ -23,6 +23,7 @@ typedef struct {
     unsigned ppn_offset_bits[5];
     unsigned entry_width_bytes;
     unsigned vpn_width_bits;
+    unsigned vaddr_bits;
 } virtual_memory_system_t;
 
 static virtual_memory_system_t sv32 = {
@@ -31,7 +32,8 @@ static virtual_memory_system_t sv32 = {
     .ppn_width_bits = {12, 10, 10},
     .ppn_offset_bits = {0, 12, 22},
     .entry_width_bytes = 4,
-    .vpn_width_bits = 10
+    .vpn_width_bits = 10,
+    .vaddr_bits = 32
 };
 
 static virtual_memory_system_t sv39 = {
@@ -40,7 +42,8 @@ static virtual_memory_system_t sv39 = {
     .ppn_width_bits = {12, 9, 9, 26},
     .ppn_offset_bits = {0, 12, 21, 30},
     .entry_width_bytes = 8,
-    .vpn_width_bits = 9
+    .vpn_width_bits = 9,
+    .vaddr_bits = 39
 };
 
 static virtual_memory_system_t sv48 = {
@@ -49,7 +52,8 @@ static virtual_memory_system_t sv48 = {
     .ppn_width_bits = {12, 9, 9, 9, 26},
     .ppn_offset_bits = {0, 12, 21, 30, 39},
     .entry_width_bytes = 8,
-    .vpn_width_bits = 9
+    .vpn_width_bits = 9,
+    .vaddr_bits = 48
 };
 
 static virtual_memory_system_t *vms;
@@ -152,12 +156,20 @@ int main()
     void *master_table = get_page();
     setup_page_table(master_table, vms->levels-1, 0);
     uint32_t *physical = get_page();
-    uint32_t *virtual = (uint32_t *) (((reg_t) physical) ^ ((reg_t) 0x40000000));
+    //uint32_t *virtual = (uint32_t *) (((reg_t) physical) ^ ((reg_t) 0x40000000));
+    uint32_t *virtual = (uint32_t *) (((reg_t) physical) ^ (((reg_t) 0xf) << (vms->vaddr_bits - 4)));
+    // Virtual addresses must be sign-extended.
+    if (vms->vaddr_bits < sizeof(virtual) * 8 && (reg_t) virtual & ((reg_t) 1<<(vms->vaddr_bits-1)))
+        virtual = (uint32_t *) (
+                (reg_t) virtual | ~(((reg_t) 1 << vms->vaddr_bits) - 1));
     add_entry(master_table, 0, (reg_t) virtual, (reg_t) physical);
 
     unsigned long satp = set_field(0, SATP_MODE, vms->mode);
     satp = set_field(satp, SATP_PPN, ((unsigned long) master_table) >> 12);
     write_csr(satp, satp);
+    satp = read_csr(satp);
+    if (get_field(satp, SATP_MODE) != vms->mode)
+        error();
 
     reg_t mstatus = read_csr(mstatus);
     mstatus |= MSTATUS_MPRV;

debug/testlib.py

@@ -1076,6 +1076,17 @@ def parkOtherHarts(self):
 
         self.gdb.select_hart(self.hart)
 
+    def disable_pmp(self):
+        # Disable physical memory protection by allowing U mode access to all
+        # memory.
+        try:
+            self.gdb.p("$pmpcfg0=0xf")  # TOR, R, W, X
+            self.gdb.p("$pmpaddr0=0x%x" %
+                    ((self.hart.ram + self.hart.ram_size) >> 2))
+        except CouldNotFetch:
+            # PMP registers are optional
+            pass
+
 class GdbSingleHartTest(GdbTest):
     def classSetup(self):
         GdbTest.classSetup(self)