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#include "scheduler.h"
#include "api/error.h"
#include "hal/smp.h"
#include "lib/printf.h"
#include "sys/objdir.h"
#include "proc/init.h"
#include "proc/process.h"
#include "proc/ipc.h"
//TODO: Better scheduling algorithm than round robin.
static struct pcb_header *s_running_list;
static struct pcb_header *s_ready_queue;
static struct pcb_header *s_mail_queue;
static uintmax_t s_this_tick;
static inline void
s_scheduler_swap_pcb(processor_t *proc, pcb_t *current_pcb, pcb_t *target_pcb)
{
jove_owned_obj_t *target_rootdir = obj_take(pcb_getrootdir(target_pcb));
jove_owned_obj_t *target_pcb_obj = pcb_getself(target_rootdir);
jove_obj_t target_pagedir = objdir_peeklocal(target_rootdir, PCB_ROOTDIR_PAGEDIR_I);
obj_release(target_rootdir);
processor_setpcb(proc, target_pcb_obj);
_scheduler_switch_pcb_arch(target_pcb);
scheduler_switch(
pcb_getksp_ref(current_pcb),
pcb_getksp(target_pcb),
(void*)obj_getvalue((jove_owned_obj_t*)&target_pagedir));
}
int scheduler_yield(pid_t target_pid)
{
processor_t *proc = processor_current();
pcb_t *current_pcb = obj_deref(processor_getpcb(proc));
pcb_t *target_pcb = (pcb_t*)((struct pcb_header*)current_pcb)->sched_next;
if(target_pid != 0) {
pcb_t *target_pcb = pcb_frompid(target_pid);
}
if(target_pcb == 0) {
return -EBADPROC;
}
scheduler_savestate();
s_scheduler_swap_pcb(proc, current_pcb, target_pcb);
scheduler_restorestate();
return 0;
}
void
s_enqueue_pcb(struct pcb_header *pcb, struct pcb_header *list)
{
if(pcb->sched_prev) pcb->sched_prev->sched_next = pcb->sched_next;
if(pcb->sched_prev) pcb->sched_next->sched_prev = pcb->sched_prev;
list->sched_prev = pcb;
pcb->sched_next = list;
pcb->sched_prev = NULL;
}
void
scheduler_block_for_mail(struct pcb_header *pcb, uintmax_t timeout, pid_t yield_target)
{
ipc_klogf("Blocking PID %i for %i ticks for %i\n",
pcb_getpid((pcb_t*)pcb), timeout, yield_target);
pcb->state = PCB_STATE_BLOCKED_MAIL;
s_enqueue_pcb(pcb, s_mail_queue);
s_mail_queue = pcb;
pcb->block_until = s_this_tick + timeout;
scheduler_yield(yield_target);
}
void
s_schedule_ready_queue(void)
{
for(struct pcb_header *pcb = s_ready_queue; pcb; pcb = s_ready_queue) {
s_ready_queue = pcb->sched_next;
//Add this process to the ready list after the last ready process.
pcb->state = PCB_STATE_READY;
s_enqueue_pcb(pcb, s_running_list);
s_running_list = pcb;
}
}
void
s_schedule_mail_queue(void)
{
struct pcb_header *pcb = s_mail_queue;
while(pcb) {
struct pcb_header *next_pcb = pcb->sched_next;
struct port *pcb_port = pcb_getport((pcb_t*)pcb);
if(port_poll_send(pcb_port)) {
//Send buffer is full. Try to transfer to target recv buffer.
//First check if the target recv buffer has space.
struct port *recv_port = port_get_send_target(pcb_port);
if(port_poll_recv(recv_port)) continue;
//Now check if the recv buffer is accepting from this port.
struct port *recv_target = port_get_recv_target(recv_port);
if(recv_target != 0 && pcb_port != recv_target) continue;
//This never hits, but if things change in impl we may have to abort here.
if(port_recv(recv_port, pcb_port) < 0) continue;
s_enqueue_pcb(pcb, s_running_list);
s_running_list = pcb;
}
if(port_poll_recv(pcb_port)) {
//Recv buffer is full, so unblock.
s_enqueue_pcb(pcb, s_running_list);
s_running_list = pcb;
}
if(s_this_tick >= pcb->block_until) {
ipc_klogf("Unblocking %i due to timeout\n", pcb_getpid((pcb_t*)pcb));
s_enqueue_pcb(pcb, s_running_list);
s_running_list = pcb;
}
loop_end:
pcb = next_pcb;
}
}
void
scheduler_tick()
{
size_t last_tick = s_this_tick++;
s_schedule_ready_queue();
s_schedule_mail_queue();
processor_t *proc = processor_current();
struct pcb_header *current_pcb = obj_deref(processor_getpcb(proc));
struct pcb_header *next_pcb = s_running_list;
struct pcb_header *tail = next_pcb;
while(tail->sched_next) {
tail = tail->sched_next;
if(tail == next_pcb) break;
}
tail->sched_next = next_pcb;
next_pcb->sched_prev = tail;
s_running_list = next_pcb->sched_next;
s_scheduler_swap_pcb(proc, (pcb_t*)current_pcb, (pcb_t*)next_pcb);
}
void scheduler_init(jove_owned_obj_t *pcb_obj, void *process_main)
{
struct pcb_header *pcb_header = obj_deref(pcb_obj);
pcb_header->state = PCB_STATE_RUNNING;
processor_t *proc = processor_current();
processor_setpcb(proc, pcb_obj);
jove_owned_obj_t syscall_stack = init_pop_alloc();
jove_owned_obj_t interrupt_stack = init_pop_alloc();
pcb_set_syscall_stack((pcb_t*)pcb_header, obj_getvalue(&syscall_stack));
pcb_set_interrupt_stack((pcb_t*)pcb_header, obj_getvalue(&interrupt_stack));
kprintf("Syscall stack %p %p\n", *__syscall_stack_mapping, pcb_get_syscall_stack((pcb_t*)pcb_header));
kprintf("Interrupt stack %p %p\n", *__interrupt_stack_mapping, pcb_get_interrupt_stack((pcb_t*)pcb_header));
_scheduler_switch_pcb_arch((pcb_t*)pcb_header);
jove_owned_obj_t *pagedir_obj = pcb_getpagedir(_rootdir_obj);
void *pagedir = (void*)obj_getvalue(pagedir_obj);
obj_release(pagedir_obj);
pcb_map_syscall_stack((pcb_t*)pcb_header);
pcb_map_interrupt_stack((pcb_t*)pcb_header);
s_running_list = pcb_header;
__asm__ volatile("\
movq %0, %%rsp; \
xorq %%rbp, %%rbp; \
jmpq %1":: "r"(pcb_header->ksp), "r"(process_main));
}
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