cleanup

apps/sys_proc.c

@@ -13,11 +13,9 @@
 
 /* same as the struct pcb_intf in grass/process.h */
 struct pcb_intf {
- long long (*timer_reset)();
  int (*proc_alloc)();
  void (*proc_free)(int);
- void (*proc_set_running)(int);
- void (*proc_set_runnable)(int);
+ void (*proc_set_ready)(int);
 } pcb;
 
 int main(struct pcb_intf* _pcb) {
@@ -29,9 +27,5 @@ int main(struct pcb_intf* _pcb) {
  FATAL("Process ID mismatch: %d != %d", file_pid, GPID_FILE);
  INFO("Load kernel process #%d: file server", file_pid);
 
-
- earth->intr_enable();
- pcb.timer_reset();
-
  while (1);
 }

grass/grass.c

@@ -18,19 +18,21 @@ static void sys_proc_init();
 int main() {
  SUCCESS("Enter the grass layer");
 
- proc_init(); // process control block
- timer_init(); // timer
- sys_proc_init(); // first kernel process
-
- void (*app_entry)(void*) = (void*)VADDR_START;
- pcb.timer_reset = timer_reset;
- pcb.proc_alloc = proc_alloc;
- pcb.proc_set_running = proc_set_running;
- pcb.proc_set_runnable = proc_set_runnable;
-
- earth->mmu_switch(GPID_PROCESS);
- proc_set_running(GPID_PROCESS);
- app_entry(&pcb);
+ /* Initialization */
+ proc_init(); // process control block
+ timer_init(); // timer
+ sys_proc_init(); // first kernel process
+ pcb.proc_alloc = proc_alloc; // pcb interface to sys_proc
+ pcb.proc_free = proc_free;
+ pcb.proc_set_ready = proc_set_ready;
+
+ /* Enter kernel process sys_proc */
+ void (*sys_proc_entry)(void*) = (void*)VADDR_START;
+ earth->mmu_switch(GPID_PROCESS); // setup virtual address space
+ proc_set_running(GPID_PROCESS); // set status
+ timer_reset(); // start timer
+ earth->intr_enable(); // enable interrupt
+ sys_proc_entry(&pcb);
  FATAL("Should never return to the grass kernel main()");
 
  return 0;
@@ -41,12 +43,8 @@ static int read_sys_proc(int block_no, char* dst) {
 }
 
 static void sys_proc_init() {
- int pid = proc_alloc();
- if (pid != GPID_PROCESS)
- FATAL("Process ID mismatch: %d != %d", pid, GPID_PROCESS);
-
- INFO("Load kernel process #%d: process spawn and kill", pid);
+ INFO("Load kernel process #%d: process spawn and kill", GPID_PROCESS);
  struct block_store bs;
  bs.read = read_sys_proc;
- elf_load(pid, &bs, earth);
+ elf_load(GPID_PROCESS, &bs, earth);
 }

grass/grass.h

@@ -15,9 +15,9 @@ struct earth *earth;
 #define RISCV_CLINT0_MTIMECMP_BASE 0x2004000
 
 void proc_init();
-int proc_alloc();
+int  proc_alloc();
 void proc_free(int);
-void proc_set_runnable(int);
+void proc_set_ready (int);
 void proc_set_running (int);
 
 void timer_init();

grass/process.c

@@ -22,8 +22,29 @@ void proc_init() {
 
  proc_nprocs = 0;
  memset(proc_set, 0, sizeof(struct process) * MAX_NPROCESS);
+
+ /* the first process is now running */
+ int pid = proc_alloc();
+ proc_set_running(pid);
 }
 
+static void timer_or_syscall(int id) {
+ if (id == INTR_ID_TMR) {
+ /* timer interrupt for scheduling */
+ timer_reset();
+ } else if (id == INTR_ID_SOFT) {
+ /* software interrupt for system call */
+ struct syscall *sc = (struct syscall*)SYSCALL_ARGS_BASE;
+ sc->type = SYS_UNUSED;
+ *((int*)RISCV_CLINT0_MSIP_BASE) = 0;
+
+ INFO("Got system call #%d with arg %d", sc->type, sc->args.exit.status); 
+ } else {
+ FATAL("Got unknown interrupt #%d", id);
+ }
+}
+
+
 int proc_alloc() {
  proc_nprocs++;
  for (int i = 0; i < MAX_NPROCESS; i++) {
@@ -37,36 +58,27 @@ int proc_alloc() {
  return -1;
 }
 
-void proc_set_running(int pid) {
+static void proc_set_status(int pid, int status) {
  for (int i = 0; i < MAX_NPROCESS; i++) {
  if (proc_set[i].pid == pid) {
- proc_set[i].status = PROC_RUNNING;
+ proc_set[i].status = status;
  return;
  }
  }
 }
 
-void proc_set_runnable(int pid) {
- for (int i = 0; i < MAX_NPROCESS; i++) {
- if (proc_set[i].pid == pid) {
- proc_set[i].status = PROC_RUNNABLE;
- return;
- }
- } 
+void proc_free(int pid) {
+ FATAL("proc_free not implemented");
 }
 
-static void timer_or_syscall(int id) {
- if (id == INTR_ID_TMR) {
- /* timer interrupt for scheduling */
- timer_reset();
- } else if (id == INTR_ID_SOFT) {
- /* software interrupt for system call */
- struct syscall *sc = (struct syscall*)SYSCALL_ARGS_BASE;
- sc->type = SYS_UNUSED;
- *((int*)RISCV_CLINT0_MSIP_BASE) = 0;
+void proc_set_ready(int pid) {
+ proc_set_status(pid, PROC_READY);
+}
 
- INFO("Got system call #%d with arg %d", sc->type, sc->args.exit.status); 
- } else {
- FATAL("Got unknown interrupt #%d", id);
- }
+void proc_set_running(int pid) {
+ proc_set_status(pid, PROC_RUNNING);
+}
+
+void proc_set_runnable(int pid) {
+ proc_set_status(pid, PROC_RUNNABLE);
 }

grass/process.h

@@ -2,6 +2,7 @@
 
 enum {
  PROC_UNUSED,
+ PROC_READY, // loaded into memory but haven't started running
  PROC_RUNNING,
  PROC_RUNNABLE,
 };
@@ -13,9 +14,7 @@ struct process{
 
 /* interface for kernel process sys_proc */
 struct pcb_intf {
- long long (*timer_reset)();
  int (*proc_alloc)();
  void (*proc_free)(int);
- void (*proc_set_running)(int);
- void (*proc_set_runnable)(int);
+ void (*proc_set_ready)(int);
 };