tests: Add tests for the PVR

The PVR is a privileged read-only SPR. Test reading and writing in both
supervisor and problem state. In supervisor state reading returns
microwatt's assigned PVR number and writing is a noop. In problem state
both reading and writing cause privileged instruction interrupts.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>

tests/misc/head.S

@@ -16,6 +16,7 @@
  */
 
 #define STACK_TOP 0x2000
+#define PVR	287
 
 /* Load an immediate 64-bit value into a register */
 #define LOAD_IMM64(r, e)			\
@@ -100,3 +101,39 @@ test_addpcis_2:
 
     blr
 
+/* Test reading the PVR */
+.global test_mfpvr
+test_mfpvr:
+    mflr %r0
+    std %r0, 16(%r1)
+    stdu %r1, -32(%r1)
+
+    /*
+     * If r3 happened to already contain PVR_MICROWATT the test
+     * would succeed even if the PVR is not implemented.
+     */
+    LOAD_IMM64(%r3, 0xdeadbeef)
+    mfpvr %r3
+
+    addi %r1, %r1, 32
+    ld %r0, 16(%r1)
+    mtlr %r0
+
+    blr
+
+/* Test writing the PVR does nothing */
+.global test_mtpvr
+test_mtpvr:
+    mflr %r0
+    std %r0, 16(%r1)
+    stdu %r1, -32(%r1)
+
+    LOAD_IMM64(%r3, 0xdeadbeef)
+    mtspr PVR, %r3
+    mfpvr %r3
+
+    addi %r1, %r1, 32
+    ld %r0, 16(%r1)
+    mtlr %r0
+
+    blr

tests/misc/misc.c

@@ -8,8 +8,12 @@
 #define PASS "PASS\n"
 #define FAIL "FAIL\n"
 
+#define PVR_MICROWATT 0x00630000
+
 extern long test_addpcis_1(void);
 extern long test_addpcis_2(void);
+extern long test_mfpvr(void);
+extern long test_mtpvr(void);
 
 // i < 100
 void print_test_number(int i)
@@ -40,5 +44,19 @@ int main(void)
 	} else
 		puts(PASS);
 
+	print_test_number(3);
+	if (test_mfpvr() != PVR_MICROWATT) {
+		fail = 1;
+		puts(FAIL);
+	} else
+		puts(PASS);
+
+	print_test_number(4);
+	if (test_mtpvr() != PVR_MICROWATT) {
+		fail = 1;
+		puts(FAIL);
+	} else
+		puts(PASS);
+
 	return fail;
 }

tests/privileged/privileged.c

@@ -15,6 +15,7 @@ extern int call_with_msr(unsigned long arg, int (*fn)(unsigned long), unsigned l
 #define SRR1	27
 #define PID	48
 #define PRTBL	720
+#define PVR	287
 
 static inline unsigned long mfspr(int sprnum)
 {
@@ -186,6 +187,20 @@ int priv_fn_6(unsigned long x)
 	return 0;
 }
 
+int priv_fn_7(unsigned long x)
+{
+	mfspr(PVR);
+	__asm__ volatile("sc");
+	return 0;
+}
+
+int priv_fn_8(unsigned long x)
+{
+	mtspr(PVR, x);
+	__asm__ volatile("sc");
+	return 0;
+}
+
 int priv_test(int (*fn)(unsigned long))
 {
 	unsigned long msr;
@@ -239,6 +254,8 @@ int main(void)
 	do_test(4, priv_fn_4);
 	do_test(5, priv_fn_5);
 	do_test(6, priv_fn_6);
+	do_test(7, priv_fn_7);
+	do_test(8, priv_fn_8);
 
 	return fail;
 }

tests/test_misc.console_out

@@ -1,2 +1,4 @@
 Test 01:PASS
 Test 02:PASS
+Test 03:PASS
+Test 04:PASS

tests/test_privileged.console_out

@@ -4,3 +4,5 @@ test 03:PASS
 test 04:PASS
 test 05:PASS
 test 06:PASS
+test 07:PASS
+test 08:PASS