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// MIT License, Copyright (c) 2020 Marvin Borner
#include <assert.h>
#include <boot.h>
#include <cpu.h>
#include <interrupts.h>
#include <list.h>
#include <load.h>
#include <mem.h>
#include <print.h>
#include <proc.h>
#include <str.h>
#include <timer.h>
u32 current_pid = 0;
u32 quantum = 0;
struct proc *priority_proc;
struct list *proc_list;
struct node *current;
// TODO: Use less memcpy and only copy relevant registers
// TODO: 20 priority queues (https://www.kernel.org/doc/html/latest/scheduler/sched-nice-design.html)
void scheduler(struct regs *regs)
{
timer_handler();
if (quantum == 0) {
quantum = PROC_QUANTUM;
} else {
quantum--;
return;
}
assert(proc_list->head);
if (current)
memcpy(&((struct proc *)current->data)->regs, regs, sizeof(struct regs));
if (priority_proc && priority_proc->state == PROC_RUNNING) {
current = list_first_data(proc_list, priority_proc);
priority_proc = NULL;
assert(current);
} else if (current && current->next &&
((struct proc *)current->next->data)->state == PROC_RUNNING) {
current = current->next;
} else if (((struct proc *)proc_list->head->data)->state == PROC_RUNNING) {
current = proc_list->head;
} else {
print("TODO: All processes are sleeping!\n"); // TODO!
/* loop(); */
}
memcpy(regs, &((struct proc *)current->data)->regs, sizeof(struct regs));
if (regs->cs != GDT_USER_CODE_OFFSET) {
regs->gs = GDT_USER_DATA_OFFSET;
regs->fs = GDT_USER_DATA_OFFSET;
regs->es = GDT_USER_DATA_OFFSET;
regs->ds = GDT_USER_DATA_OFFSET;
regs->ss = GDT_USER_DATA_OFFSET;
regs->cs = GDT_USER_CODE_OFFSET;
regs->eflags = EFLAGS_ALWAYS | EFLAGS_INTERRUPTS;
}
/* printf("{%d}", ((struct proc *)current->data)->pid); */
}
void scheduler_enable(void)
{
timer_install();
irq_install_handler(0, scheduler);
}
void scheduler_disable(void)
{
irq_uninstall_handler(0);
timer_install();
}
void proc_print(void)
{
struct node *node = proc_list->head;
printf("\nPROCESSES\n");
struct proc *proc = NULL;
while (node && (proc = node->data)) {
printf("Process %d: %s [%s]\n", proc->pid, proc->name,
proc->state == PROC_RUNNING ? "RUNNING" : "SLEEPING");
node = node->next;
}
printf("\n");
}
struct proc *proc_current(void)
{
return current && current->data ? current->data : NULL;
}
void proc_send(struct proc *src, struct proc *dest, u32 type, void *data)
{
// TODO: Use unique key instead of pid for IPC
if (!src || !dest)
return;
struct proc_message *msg = malloc(sizeof(*msg));
msg->src = src;
msg->dest = dest;
msg->msg = malloc(sizeof(struct message));
msg->msg->src = (int)src->pid;
msg->msg->type = (int)type;
msg->msg->data = data;
list_add(dest->messages, msg);
priority_proc = dest;
}
struct proc_message *proc_receive(struct proc *proc)
{
if (proc->messages && proc->messages->head) {
struct proc_message *msg = proc->messages->head->data;
list_remove(proc->messages, proc->messages->head);
return msg;
} else {
return NULL;
}
}
struct proc *proc_from_pid(u32 pid)
{
struct node *iterator = proc_list->head;
while (iterator != NULL) {
if (((struct proc *)iterator->data)->pid == pid)
return iterator->data;
iterator = iterator->next;
}
return NULL;
}
void proc_exit(struct proc *proc, int status)
{
assert(proc);
int res = 0;
struct node *iterator = proc_list->head;
while (iterator != NULL) {
if (iterator->data == proc) {
res = 1;
list_remove(proc_list, iterator);
break;
}
iterator = iterator->next;
}
if (memcmp(proc, current->data, sizeof(*proc)) == 0)
current = NULL;
if (res)
printf("Process %s exited with status %d\n", proc->name, status);
quantum = 0; // TODO: Add quantum to each process struct?
}
void proc_yield(struct regs *r)
{
quantum = 0;
scheduler(r);
}
struct proc *proc_make(void)
{
struct proc *proc = malloc(sizeof(*proc));
proc->pid = current_pid++;
proc->messages = list_new();
proc->state = PROC_RUNNING;
if (current)
list_add(proc_list, proc);
return proc;
}
extern void proc_jump_userspace(void);
u32 _esp, _eip;
void proc_init(void)
{
if (proc_list)
return;
cli();
scheduler_enable();
proc_list = list_new();
kernel_proc = proc_make();
struct node *new = list_add(proc_list, proc_make());
bin_load((char *)"/bin/init", new->data);
current = new;
_eip = ((struct proc *)new->data)->regs.eip;
_esp = ((struct proc *)new->data)->regs.useresp;
u32 argc = 2;
char **argv = malloc(sizeof(*argv) * (argc + 1));
argv[0] = strdup("init");
argv[1] = (char *)boot_passed->vbe;
argv[2] = NULL;
((u32 *)_esp)[0] = argc; // First argument (argc)
((u32 *)_esp)[1] = (u32)argv; // Second argument (argv)
proc_jump_userspace();
while (1) {
};
}
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