trapslab initialized

user/alarmtest.c

@@ -0,0 +1,193 @@
+//
+// test program for the alarm lab.
+// you can modify this file for testing,
+// but please make sure your kernel
+// modifications pass the original
+// versions of these tests.
+//
+
+#include "kernel/param.h"
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "kernel/riscv.h"
+#include "user/user.h"
+
+void test0();
+void test1();
+void test2();
+void test3();
+void periodic();
+void slow_handler();
+void dummy_handler();
+
+int
+main(int argc, char *argv[])
+{
+  test0();
+  test1();
+  test2();
+  test3();
+  exit(0);
+}
+
+volatile static int count;
+
+void
+periodic()
+{
+  count = count + 1;
+  printf("alarm!\n");
+  sigreturn();
+}
+
+// tests whether the kernel calls
+// the alarm handler even a single time.
+void
+test0()
+{
+  int i;
+  printf("test0 start\n");
+  count = 0;
+  sigalarm(2, periodic);
+  for(i = 0; i < 1000*500000; i++){
+    if((i % 1000000) == 0)
+      write(2, ".", 1);
+    if(count > 0)
+      break;
+  }
+  sigalarm(0, 0);
+  if(count > 0){
+    printf("test0 passed\n");
+  } else {
+    printf("\ntest0 failed: the kernel never called the alarm handler\n");
+  }
+}
+
+void __attribute__ ((noinline)) foo(int i, int *j) {
+  if((i % 2500000) == 0) {
+    write(2, ".", 1);
+  }
+  *j += 1;
+}
+
+//
+// tests that the kernel calls the handler multiple times.
+//
+// tests that, when the handler returns, it returns to
+// the point in the program where the timer interrupt
+// occurred, with all registers holding the same values they
+// held when the interrupt occurred.
+//
+void
+test1()
+{
+  int i;
+  int j;
+
+  printf("test1 start\n");
+  count = 0;
+  j = 0;
+  sigalarm(2, periodic);
+  for(i = 0; i < 500000000; i++){
+    if(count >= 10)
+      break;
+    foo(i, &j);
+  }
+  if(count < 10){
+    printf("\ntest1 failed: too few calls to the handler\n");
+  } else if(i != j){
+    // the loop should have called foo() i times, and foo() should
+    // have incremented j once per call, so j should equal i.
+    // once possible source of errors is that the handler may
+    // return somewhere other than where the timer interrupt
+    // occurred; another is that that registers may not be
+    // restored correctly, causing i or j or the address ofj
+    // to get an incorrect value.
+    printf("\ntest1 failed: foo() executed fewer times than it was called\n");
+  } else {
+    printf("test1 passed\n");
+  }
+}
+
+//
+// tests that kernel does not allow reentrant alarm calls.
+void
+test2()
+{
+  int i;
+  int pid;
+  int status;
+
+  printf("test2 start\n");
+  if ((pid = fork()) < 0) {
+    printf("test2: fork failed\n");
+  }
+  if (pid == 0) {
+    count = 0;
+    sigalarm(2, slow_handler);
+    for(i = 0; i < 1000*500000; i++){
+      if((i % 1000000) == 0)
+        write(2, ".", 1);
+      if(count > 0)
+        break;
+    }
+    if (count == 0) {
+      printf("\ntest2 failed: alarm not called\n");
+      exit(1);
+    }
+    exit(0);
+  }
+  wait(&status);
+  if (status == 0) {
+    printf("test2 passed\n");
+  }
+}
+
+void
+slow_handler()
+{
+  count++;
+  printf("alarm!\n");
+  if (count > 1) {
+    printf("test2 failed: alarm handler called more than once\n");
+    exit(1);
+  }
+  for (int i = 0; i < 1000*500000; i++) {
+    asm volatile("nop"); // avoid compiler optimizing away loop
+  }
+  sigalarm(0, 0);
+  sigreturn();
+}
+
+//
+// dummy alarm handler; after running immediately uninstall
+// itself and finish signal handling
+void
+dummy_handler()
+{
+  sigalarm(0, 0);
+  sigreturn();
+}
+
+//
+// tests that the return from sys_sigreturn() does not
+// modify the a0 register
+void
+test3()
+{
+  uint64 a0;
+
+  sigalarm(1, dummy_handler);
+  printf("test3 start\n");
+
+  asm volatile("lui a5, 0");
+  asm volatile("addi a0, a5, 0xac" : : : "a0");
+  for(int i = 0; i < 500000000; i++)
+    ;
+  asm volatile("mv %0, a0" : "=r" (a0) );
+
+  if(a0 != 0xac)
+    printf("test3 failed: register a0 changed\n");
+  else
+    printf("test3 passed\n");
+}