331 lines
11 KiB
C
331 lines
11 KiB
C
#include "cpu/halt.h"
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#include "cpu/paging.h"
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#include "cpu/serial.h"
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#include "cpu/tasking_helpers.h"
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#include "kmalloc.h"
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#include "tasking.h"
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#include <sys/types.h>
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#define MAX_PROCS 32768
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#define HAS_UNBLOCKED_THREADS(proc) (proc->numThreads!=proc->numThreadsBlocked)
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#define NUM_UNBLOCKED_THREADS(proc) (proc->numThreads-proc->numThreadsBlocked)
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#define SAME_PROC(thread1,thread2) (thread1->process->pid==thread2->process->pid)
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#define SAME_THREAD(thread1,thread2) (thread1->process->pid==thread2->process->pid&&thread1->tid==thread2->tid)
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pid_t next_pid=0;
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size_t num_procs=0;
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Process* processes[MAX_PROCS];
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char proc_schedule_bmap[MAX_PROCS/8];
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Thread* currentThread;
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static Thread* readyToRunHead=NULL;
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static Thread* readyToRunTail=NULL;
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static char is_proc_scheduled(pid_t index) {
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size_t byte=index/8;
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size_t bit=index%8;
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char entry=proc_schedule_bmap[byte];
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return (entry&(1<<bit))>0;
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}
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static void mark_proc_scheduled(pid_t index) {
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if (is_proc_scheduled(index)) {
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serial_printf("Attempt to schedule a thread in a process with a scheduled thread! (PID %d)\n",index);
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halt();
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}
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size_t byte=index/8;
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size_t bit=index%8;
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proc_schedule_bmap[byte]=proc_schedule_bmap[byte]|(1<<bit);
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}
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static void unmark_proc_scheduled(pid_t index) {
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size_t byte=index/8;
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size_t bit=index%8;
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proc_schedule_bmap[byte]=proc_schedule_bmap[byte]&(~(1<<bit));
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}
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void tasking_createTask(void* eip,void* cr3,char kmode,char param1_exists,void* param1_arg,char param2_exists,void* param2_arg,char isThread) {
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if (next_pid>MAX_PROCS && !isThread) {
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serial_printf("Failed to create a process, as 32k processes have been created already.\n");
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halt(); //Cannot ever create more than 32k processes, as I don't currently reuse PIDs.
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}
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void* param1;
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if (param1_exists) {
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param1=param1_arg;
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} else {
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param1=NULL;
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}
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void* param2;
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if (param2_exists) {
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if (isThread) {
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serial_printf("Param2 in Thread!\n");
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halt();
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}
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param2=param2_arg;
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} else {
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param2=NULL;
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}
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Process* proc;
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Thread* thread=kmalloc(sizeof(Thread));
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if (isThread) {
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proc=processes[(pid_t)param2_arg];
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proc->numThreads++;
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thread->cr3=proc->firstThread->cr3;
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} else {
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proc=kmalloc(sizeof(Process));
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if (currentThread) {
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proc->priv=currentThread->process->priv;
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} else {
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proc->priv=1;
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}
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proc->pid=next_pid;
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next_pid++;
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proc->next_tid=0;
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proc->numThreads=1;
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proc->numThreadsBlocked=0;
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proc->firstThread=thread;
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processes[proc->pid]=proc;
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thread->cr3=cr3;
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}
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thread->process=proc;
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thread->errno=0;
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thread->tid=proc->next_tid;
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proc->next_tid++;
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setup_kstack(thread,param1,param2,kmode,eip);
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thread->prevReadyToRun=NULL;
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thread->nextReadyToRun=NULL;
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if (isThread) {
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thread->nextThreadInProcess=proc->firstThread;
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thread->prevThreadInProcess=NULL;
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thread->state=THREAD_READY;
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proc->firstThread->prevThreadInProcess=thread;
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proc->firstThread=thread;
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} else {
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thread->nextThreadInProcess=NULL;
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thread->prevThreadInProcess=NULL;
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if (!is_proc_scheduled(proc->pid)) {
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if (readyToRunTail) {
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thread->state=THREAD_READY;
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readyToRunTail->nextReadyToRun=thread;
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thread->prevReadyToRun=readyToRunTail;
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readyToRunTail=thread;
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mark_proc_scheduled(proc->pid);
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} else if (currentThread) {
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thread->state=THREAD_READY;
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readyToRunHead=thread;
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readyToRunTail=thread;
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mark_proc_scheduled(proc->pid);
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} else {
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thread->state=THREAD_RUNNING;
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currentThread=thread;
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}
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}
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}
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if (!isThread) {
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num_procs++;
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}
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serial_printf("Created thread with PID %d and TID %d.\n",proc->pid,thread->tid);
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}
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void tasking_init() {
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tasking_createTask(NULL,get_cr3(),1,0,0,0,0,0);
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}
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char tasking_isPrivleged() {
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return currentThread->process->priv;
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}
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pid_t tasking_getPID() {
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return currentThread->process->pid;
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}
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int* tasking_get_errno_address() {
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return ¤tThread->errno;
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}
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pid_t tasking_new_thread(void* start,pid_t pid,char param_exists,void* param_arg) {
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tasking_createTask(start,NULL,0,param_exists,param_arg,0,(void*)pid,1);
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return processes[pid]->firstThread->tid;
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}
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void switch_to_thread(Thread* thread) {
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// Unlink the thread from the list of ready-to-run threads
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if (thread!=readyToRunHead) {
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thread->prevReadyToRun->nextReadyToRun=thread->nextReadyToRun;
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if (thread->nextReadyToRun) {
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thread->nextReadyToRun->prevReadyToRun=thread->prevReadyToRun;
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}
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} else {
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readyToRunHead=thread->nextReadyToRun;
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if (readyToRunHead==NULL) {
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readyToRunTail=NULL;
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}
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}
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unmark_proc_scheduled(thread->process->pid);
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thread->prevReadyToRun=NULL;
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thread->nextReadyToRun=NULL;
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if (currentThread->state==THREAD_RUNNING) {
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currentThread->state=THREAD_READY;
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}
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Thread* currentThreadNextReady=currentThread->nextThreadInProcess;
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while ((currentThreadNextReady&¤tThreadNextReady->state!=THREAD_READY)||(currentThreadNextReady&&SAME_THREAD(thread,currentThreadNextReady))) {
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currentThreadNextReady=currentThreadNextReady->nextThreadInProcess;
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}
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if (!currentThreadNextReady) {
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currentThreadNextReady=currentThread->process->firstThread;
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while ((currentThreadNextReady&¤tThreadNextReady->state!=THREAD_READY)||(currentThreadNextReady&&SAME_THREAD(thread,currentThreadNextReady))) {
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currentThreadNextReady=currentThreadNextReady->nextThreadInProcess;
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}
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}
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if (!currentThreadNextReady) {
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//This process is fully blocked, try the process of the thread we're yielding to
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currentThreadNextReady=thread->nextThreadInProcess;
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while ((currentThreadNextReady&¤tThreadNextReady->state!=THREAD_READY)||(currentThreadNextReady&&SAME_THREAD(thread,currentThreadNextReady))) {
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currentThreadNextReady=currentThreadNextReady->nextThreadInProcess;
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}
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if (!currentThreadNextReady) {
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currentThreadNextReady=thread->process->firstThread;
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while ((currentThreadNextReady&¤tThreadNextReady->state!=THREAD_READY)||(currentThreadNextReady&&SAME_THREAD(thread,currentThreadNextReady))) {
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currentThreadNextReady=currentThreadNextReady->nextThreadInProcess;
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}
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}
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}
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if (currentThreadNextReady && !is_proc_scheduled(currentThread->process->pid)) {
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// Link the thread onto the list of ready to run threads
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if (readyToRunTail) {
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currentThreadNextReady->prevReadyToRun=readyToRunTail;
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readyToRunTail->nextThreadInProcess=currentThreadNextReady;
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readyToRunTail=currentThreadNextReady;
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} else {
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readyToRunHead=currentThreadNextReady;
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readyToRunTail=currentThreadNextReady;
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}
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mark_proc_scheduled(currentThread->process->pid);
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}
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serial_printf("Switching to PID %d TID %d.\n",thread->process->pid,thread->tid);
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switch_to_thread_asm(thread);
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}
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void tasking_yield() {
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serial_printf("Attempting to yield\n");
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if (readyToRunHead) {
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serial_printf("Attempting to switch to PID %d TID %d\n",readyToRunHead->process->pid,readyToRunHead->tid);
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switch_to_thread(readyToRunHead);
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} else {
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if (NUM_UNBLOCKED_THREADS(currentThread->process)>1) {
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serial_printf("The ready to run list is empty, and the current process has other unblocked threads? This is an invalid state! Halting!\n");
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halt();
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} else if (NUM_UNBLOCKED_THREADS(currentThread->process)==1) {
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serial_printf("Yield failed, no other ready processes\n");
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return;
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} else {
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if (num_procs==0) {
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serial_printf("All processes exited, halting\n");
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halt();
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} else {
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serial_printf("All threads in all processes blocked, waiting for an IRQ which unblocks a thread\n");
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// All threads in all processes blocked, so wait for an IRQ whose handler unblocks a thread.
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do { wait_for_unblocked_thread_asm(); } while (readyToRunHead==NULL);
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}
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serial_printf("Attempting to switch to PID %d TID %d\n",readyToRunHead->process->pid,readyToRunHead->tid);
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switch_to_thread(readyToRunHead);
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}
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}
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}
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void tasking_block(ThreadState newstate) {
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if (readyToRunHead&&SAME_THREAD(readyToRunHead,currentThread)) {
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readyToRunHead=readyToRunHead->nextReadyToRun;
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if (readyToRunHead==NULL) {
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readyToRunTail=NULL;
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}
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}
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if (readyToRunTail&&SAME_THREAD(readyToRunTail,currentThread)) {
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readyToRunTail=readyToRunTail->prevReadyToRun;
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if (readyToRunTail==NULL) {
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readyToRunHead=NULL;
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}
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}
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if (readyToRunHead&&readyToRunHead->nextReadyToRun) {
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for (Thread* thread=readyToRunHead->nextReadyToRun;thread!=NULL;thread=thread->nextReadyToRun) {
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if (SAME_THREAD(thread,currentThread)) {
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thread->prevReadyToRun->nextReadyToRun=thread->nextReadyToRun;
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if (thread->nextReadyToRun) {
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thread->nextReadyToRun->prevReadyToRun=thread->prevReadyToRun;
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}
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break;
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}
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}
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}
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for (Thread* thread=currentThread->process->firstThread;thread!=NULL;thread=thread->nextThreadInProcess) {
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if (thread->tid==currentThread->tid) {
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thread->state=newstate;
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}
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}
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}
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void tasking_unblock(pid_t pid,pid_t tid) {
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serial_printf("Unblocking PID %d TID %d\n",pid,tid);
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if (!processes[pid]) {
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serial_printf("PID %d does not exist!\n",pid);
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}
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Thread* thread=processes[pid]->firstThread;
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for (;thread!=NULL;thread=thread->nextThreadInProcess) {
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if (thread->tid==tid) {
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break;
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}
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}
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if (!thread) {
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serial_printf("PID %d TID %d does not exist!\n",pid,thread);
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}
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if (thread->tid!=tid) {
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serial_printf("Error! Got wrong thread! (Wanted TID %d, got TID %d)\n",tid,thread->tid);
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halt();
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}
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thread->state=THREAD_READY;
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if (!is_proc_scheduled(thread->process->pid)) {
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// Link the thread onto the list of ready to run threads
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if (readyToRunTail) {
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thread->prevReadyToRun=readyToRunTail;
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readyToRunTail->nextThreadInProcess=thread;
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readyToRunTail=thread;
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} else {
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readyToRunHead=thread;
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readyToRunTail=thread;
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}
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mark_proc_scheduled(thread->process->pid);
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}
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}
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void tasking_exit(int code) {
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serial_printf("PID %d is exiting with code %d.\n",currentThread->process->pid,code);
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if (readyToRunHead&&SAME_PROC(readyToRunHead,currentThread)) {
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readyToRunHead=readyToRunHead->nextReadyToRun;
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if (readyToRunHead==NULL) {
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readyToRunTail=NULL;
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}
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}
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if (readyToRunTail&&SAME_PROC(readyToRunTail,currentThread)) {
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readyToRunTail=readyToRunTail->prevReadyToRun;
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if (readyToRunTail==NULL) {
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readyToRunHead=NULL;
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}
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}
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if (readyToRunHead&&readyToRunHead->nextReadyToRun) {
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for (Thread* thread=readyToRunHead->nextReadyToRun;thread!=NULL;thread=thread->nextReadyToRun) {
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if (SAME_PROC(thread,currentThread)) {
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thread->prevReadyToRun->nextReadyToRun=thread->nextReadyToRun;
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if (thread->nextReadyToRun) {
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thread->nextReadyToRun->prevReadyToRun=thread->prevReadyToRun;
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}
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break;
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}
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}
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}
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unmark_proc_scheduled(currentThread->process->pid);
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for (Thread* thread=currentThread->process->firstThread;thread!=NULL;thread=thread->nextThreadInProcess) {
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thread->state=THREAD_EXITED;
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}
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currentThread->process->numThreadsBlocked=currentThread->process->numThreads;
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num_procs--;
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tasking_yield();
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}
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