Enable getcount userspace test application

This patch enables the getcount systemcall functionality.

Makefile

@@ -167,7 +167,7 @@ UPROGS=\
 	_wc\
 	_zombie\
 	_bigtest\
-	#_getcount\
+	_getcount\
 
 fs.img: mkfs README $(UPROGS)
 	./mkfs fs.img README $(UPROGS)

proc.c

@@ -36,6 +36,7 @@ allocproc(void)
 {
   struct proc *p;
   char *sp;
+  int i;
 
   acquire(&ptable.lock);
   for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
@@ -70,6 +71,10 @@ found:
   memset(p->context, 0, sizeof *p->context);
   p->context->eip = (uint)forkret;
 
+  // Initialise the syscall count array entries with 0
+  for (i = 0; i < NO_OF_SYSCALLS; i++)
+    p->syscall_count[i] = 0;
+
   return p;
 }
 

proc.h

@@ -1,5 +1,6 @@
 // Segments in proc->gdt.
 #define NSEGS     7
+#define NO_OF_SYSCALLS 22
 
 // Per-CPU state
 struct cpu {
@@ -66,6 +67,7 @@ struct proc {
   struct file *ofile[NOFILE];  // Open files
   struct inode *cwd;           // Current directory
   char name[16];               // Process name (debugging)
+  uint syscall_count[NO_OF_SYSCALLS]; // Number of particular syscalls
 };
 
 // Process memory is laid out contiguously, low addresses first:

syscall.c

@@ -98,6 +98,7 @@ extern int sys_unlink(void);
 extern int sys_wait(void);
 extern int sys_write(void);
 extern int sys_uptime(void);
+extern int sys_getcount(void);
 
 static int (*syscalls[])(void) = {
 [SYS_fork]    sys_fork,
@@ -121,6 +122,7 @@ static int (*syscalls[])(void) = {
 [SYS_link]    sys_link,
 [SYS_mkdir]   sys_mkdir,
 [SYS_close]   sys_close,
+[SYS_getcount] sys_getcount,
 };
 
 void
@@ -130,6 +132,7 @@ syscall(void)
 
   num = proc->tf->eax;
   if(num > 0 && num < NELEM(syscalls) && syscalls[num]) {
+    proc->syscall_count[num]++;
     proc->tf->eax = syscalls[num]();
   } else {
     cprintf("%d %s: unknown sys call %d\n",

syscall.h

@@ -20,3 +20,4 @@
 #define SYS_link   19
 #define SYS_mkdir  20
 #define SYS_close  21
+#define SYS_getcount 22

sysproc.c

@@ -88,3 +88,14 @@ sys_uptime(void)
   release(&tickslock);
   return xticks;
 }
+
+int
+sys_getcount(void)
+{
+  int n;
+
+  if(argint(0, &n) < 0)
+    return -1;
+
+  return proc->syscall_count[n];
+}

user.h

@@ -22,6 +22,7 @@ int getpid(void);
 char* sbrk(int);
 int sleep(int);
 int uptime(void);
+int getcount(int);
 
 // ulib.c
 int stat(char*, struct stat*);

usys.S

@@ -29,3 +29,4 @@ SYSCALL(getpid)
 SYSCALL(sbrk)
 SYSCALL(sleep)
 SYSCALL(uptime)
+SYSCALL(getcount)