Scheduler fix, User RR

src/arch/x86/syscall.c

@@ -9,6 +9,9 @@
 #include <kernel.h>
 #include <stddef.h>
 #include <io/term/term.h>
+#include <sched/process.h>
+
+extern struct process* current_process;
 
 void sys_write(unsigned int fd, const char* buf, size_t count)
 {
@@ -20,10 +23,19 @@ void sys_write(unsigned int fd, const char* buf, size_t count)
             break;
 
         case 2: //stderr
+            for (size_t i=0; i<count; i++) {
+                internal_putc(buf[i], NULL);
+            }
             break;
     }
 }
 
+void sys_exit(int error_code)
+{
+    current_process->status = DEAD;
+    DEBUG("exiting process PID=%u name=%s", current_process->pid, current_process->name);
+}
+
 /*
  * syscall_handler - System call dispatcher
  * @regs: CPU state
@@ -53,6 +65,9 @@ struct cpu_status* syscall_handler(struct cpu_status* regs)
         case 1: //sys_write
             sys_write(regs->rdi, (char*)regs->rsi, regs->rdx);
             break;
+        case 60: //sys_exit
+            sys_exit(regs->rdi);
+            break;
         default:
             regs->rax = 0xbad515ca11;
             break;

src/kmain.c

@@ -121,11 +121,14 @@ void kmain()
 
 	if (!boot_ctx.module) {
 		panic(NULL, "could not load 'hello' executable :(");
-	} 
-	if (boot_ctx.module->module_count == 1) {
+	}
+	if (boot_ctx.module->module_count == 2) {
 		file = boot_ctx.module->modules[0];
 		DEBUG("file: addr=%p size=%u", file->address, file->size);
 		process_create_user(file, "hello");
+
+		file = boot_ctx.module->modules[1];
+		process_create_user(file, "pedicel");
 	}
 	scheduler_init();
 

src/sched/scheduler.c

@@ -50,31 +50,47 @@ struct cpu_status* scheduler_schedule(struct cpu_status* context)
         panic(NULL, "current_process->context is NULL");
     }
 
-    if (current_process->next == NULL) {
-        return current_process->context;
-    }
-
     current_process->context = context;
 
-    for (;;) {
-        struct process* prev_process = current_process;
-        if (current_process->next != NULL) {
-            current_process = current_process->next;
-        } else {
-            current_process = processes_list;
-        }
-        
-        if (current_process != NULL && current_process->status == DEAD) {
-            process_delete(&prev_process, current_process);
-            current_process = NULL;
+    if (current_process->status == DEAD) {
+        struct process* dead_process = current_process;
+        struct process* next_process = (dead_process->next != NULL) ? dead_process->next : processes_list;
 
+        process_delete(&processes_list, dead_process);
+
+        if (processes_list == NULL || next_process == dead_process) {
+            current_process = idle_proc;
             return idle_proc->context;
-        } else {
-            current_process->status = RUNNING;
-            break;
         }
+
+        current_process = next_process;
+    } else if (current_process->next != NULL) {
+        current_process = current_process->next;
+    } else {
+        current_process = processes_list;
     }
 
+    for (;;) {
+        if (current_process->status == DEAD) {
+            struct process* dead_process = current_process;
+            struct process* next_process = (current_process->next != NULL) ? current_process->next : processes_list;
+
+            process_delete(&processes_list, dead_process);
+
+            if (processes_list == NULL || next_process == dead_process) {
+                current_process = idle_proc;
+                return idle_proc->context;
+            }
+
+            current_process = next_process;
+            continue;
+        }
+
+        current_process->status = RUNNING;
+        break;
+    }
+
+    // Here, we chose next running process so we load its kernel stack & page tables
     tss.rsp0 = (uint64_t)current_process->kernel_stack;
     load_cr3(VIRT_TO_PHYS((uint64_t)current_process->root_page_table));