bump-allocated PID but kheap needs fix to kmalloc more than PAGE_SIZE

src/sched/process.c

@@ -2,10 +2,14 @@
 #include "process.h"
 #include "mem/heap/kheap.h"
 #include "kernel.h"
+#include "string/string.h"
+#include "mem/gdt/gdt.h"
 
 struct process_t* processes_list;
 struct process_t* current_process;
 
+size_t next_free_pid = 0;
+
 void process_init()
 {
     processes_list = NULL;
@@ -26,16 +30,35 @@ void process_display_list(struct process_t* processes_list)
     DEBUG("NULL");
 }
 
-struct process_t* process_create()
+struct process_t* process_create(char* name, void(*function)(void*), void* arg)
 {
+    CLEAR_INTERRUPTS;
     struct process_t* proc = (struct process_t*)kmalloc(sizeof(struct process_t));
     
+    struct cpu_status_t* ctx = (struct cpu_status_t*)kmalloc(sizeof(struct cpu_status_t));
+
+    // No more memory?
     if (!proc) return NULL;
+    if (!ctx) return NULL;
 
-    proc->context = NULL;
+    strncpy(proc->name, name, PROCESS_NAME_MAX);
+    proc->pid = next_free_pid++;
     proc->status = READY;
-    proc->next = NULL;
 
+    proc->context = ctx;
+    proc->context->iret_ss = KERNEL_DATA_SEGMENT; // process will live in kernel mode
+    proc->context->iret_rsp = (uint64_t)kalloc_stack();
+    proc->context->iret_flags = 0x202; //bit 2 and 9 set (Interrupt Flag)
+    proc->context->iret_cs = KERNEL_CODE_SEGMENT;
+    proc->context->iret_rip = (uint64_t)function; // beginning of executable code
+    proc->context->rdi = (uint64_t)arg; // 1st arg is in rdi (as per x64 calling convention)
+    proc->context->rbp = 0;
+
+    proc->next = 0;
+
+    process_add(&processes_list, proc);
+
+    SET_INTERRUPTS;
     return proc;
 }
 

src/sched/process.h

@@ -1,6 +1,8 @@
 #ifndef PROCESS_H
 #define PROCESS_H
 
+#include <stddef.h>
+
 typedef enum 
 {
     READY,
@@ -8,15 +10,21 @@ typedef enum
     DEAD
 } status_t;
 
+#define PROCESS_NAME_MAX 64
+#define PROCESS_STACK_SIZE 0x100 // 64kb
+
 struct process_t
 {
+    size_t pid;
+    char name[PROCESS_NAME_MAX];
+
     status_t status;
     struct cpu_status_t* context;
     struct process_t* next;
 };
 
 void process_init();
-struct process_t* process_create();
+struct process_t* process_create(char* name, void(*function)(void*), void* arg);
 void process_add(struct process_t** processes_list, struct process_t* process);
 void process_delete(struct process_t** processes_list, struct process_t* process);
 struct process_t* process_get_next(struct process_t* process);

src/sched/scheduler.c

@@ -4,32 +4,37 @@
 extern struct process_t* processes_list;
 extern struct process_t* current_process;
 
-// DEBUG: how many times we did schedule
-int scheduled = 0;
-
 void scheduler_init()
 {
     // Choose first process?
     current_process = processes_list;
 }
 
-void scheduler_schedule()
+struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context)
 {
-    //DEBUG("Scheduler called!");
-    if (current_process->next != NULL)
-    {
-        current_process = current_process->next;
-    } else
-    {
-        current_process = processes_list;
-    }
-    scheduled++;
-    DEBUG("SCHEDULER CALLED: current_process=%p", current_process);
+    current_process->context = context;
+    current_process->status = READY;
 
-    // debug
-    /* if (scheduled == 5)
-    {
-        DEBUG("enough, halting");
-        hcf();
-    } */
+    for (;;) {
+        struct process_t* 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);
+        } else
+        {
+            current_process->status = RUNNING;
+            break;
+        }
+    }
+    
+    DEBUG("SCHEDULER CALLED: current_process=%p", current_process);
+    return current_process->context;
 }