kernel threads

kernel threads and preemptive multitasking

src/arch/x86_64/Makefile

@@ -1,4 +1,4 @@
-objects := $(patsubst %.c,%.o,$(wildcard *.c)) israsm.o
+objects := $(patsubst %.c,%.o,$(wildcard *.c)) israsm.o context.o
 subdirs=boot
 OBJPATH=$(OBJDIR)/arch/${TARGET}/
 export
@@ -15,3 +15,7 @@ israsm.o: isr.asm
 	nasm -f elf64 -o $@ $<
 	mkdir -p $(OBJPATH)
 	cp $@ $(OBJPATH)/$@
+context.o: context.asm
+	nasm -f elf64 -o $@ $<
+	mkdir -p $(OBJPATH)
+	cp $@ $(OBJPATH)/$@

src/arch/x86_64/context.asm

@@ -0,0 +1,32 @@
+global arch_switchcontext
+arch_switchcontext:
+	mov rsp,rdi
+	add rsp, 8 ; cr2
+        pop rax
+        mov gs,rax
+        pop rax
+        mov fs,rax
+        pop rax
+        mov es,rax
+        pop rax
+        mov ds,rax
+        pop rax
+        pop rbx
+        pop rcx
+        pop rdx
+        pop r8
+        pop r9
+        pop r10
+        pop r11
+        pop r12
+        pop r13
+        pop r14
+        pop r15
+        pop rdi
+        pop rsi
+        pop rbp
+        add rsp,8 ; remove error code
+	
+	swapgs
+	
+	iretq

src/arch/x86_64/include/arch/cls.h

@@ -22,6 +22,7 @@ typedef struct{
 	thread_t* thread;
 	size_t timerticksperus;
 	timer_req* timerfirstreq;
+	timer_req  schedreq;
 } cls_t;
 
 void bsp_setcls();

src/arch/x86_64/include/arch/kstack.h

@@ -0,0 +1,6 @@
+#ifndef _KSTACK_H_INCLUDE
+#define _KSTACK_H_INCLUDE
+
+void arch_setkernelstack(void*);
+
+#endif

src/arch/x86_64/include/arch/regs.h

@@ -2,10 +2,12 @@
 #define _REGS_H_INCLUDE
 
 #include <stdint.h>
+#include <stdbool.h>
 
 typedef struct{
         uint64_t cr2,gs,fs,es,ds,rax,rbx,rcx,rdx,r8,r9,r10,r11,r12,r13,r14,r15,rdi,rsi,rbp,error,rip,cs,rflags,rsp,ss;
 } arch_regs;
 
+void arch_regs_setupkernel(arch_regs* regs, void* ip, void* stack, bool interrupts);
 
 #endif

src/arch/x86_64/isr.asm

@@ -75,7 +75,7 @@ section .text
 	pop rdi
 	pop rsi
 	pop rbp
-
+	add rsp,8 ; remove error code
 
 %endmacro
 
@@ -96,8 +96,6 @@ section .text
 	
 	popregs
 
-	add rsp,8 ; remove error code
-
 	iretq
 	
 	
@@ -121,8 +119,6 @@ section .text
 	
 	popregs
 	
-	add rsp,8 ; remove error code
-
 	iretq
 %endmacro
 

src/arch/x86_64/kstack.c

@@ -0,0 +1,8 @@
+#include <arch/kstack.h>
+#include <arch/ist.h>
+#include <arch/cls.h>
+
+void arch_setkernelstack(void* stack){
+	
+	arch_getcls()->ist.rsp0 = (uint64_t)stack;
+}

src/arch/x86_64/main.c

@@ -28,9 +28,7 @@ struct limine_terminal_response* liminetty;
 int  ttylock = 0;
 
 void liminewrite(char* str, size_t c){
-
 	liminetty->write(liminetty->terminals[0], str, c);
-
 }
 
 void kmain(){
@@ -80,6 +78,8 @@ void kmain(){
 
 	pci_enumerate();
 
+	sched_init();
+
 	smp_init();
 
 	_panic("End of kmain()", 0);

src/arch/x86_64/regs.c

@@ -0,0 +1,13 @@
+#include <arch/regs.h>
+
+void arch_regs_setupkernel(arch_regs* regs, void* ip, void* stack, bool interrupts){
+        regs->rip = ip;
+        regs->rsp = stack;
+        regs->cs = 0x28;
+        regs->ds = 0x30;
+        regs->es = 0x30;
+        regs->fs = 0x30;
+        regs->gs = 0x30;
+        regs->ss = 0x30;
+        regs->rflags = interrupts ? 0x200 : 0;	
+}

src/include/kernel/sched.h

@@ -5,18 +5,29 @@
 #include <arch/regs.h>
 #include <kernel/vfs.h>
 
+#define THREAD_PRIORITY_INTERRUPT 0
+#define THREAD_PRIORITY_KERNEL 1
+#define THREAD_PRIORITY_USER 2
+
 #define THREAD_STATE_WAITING 0
 #define THREAD_STATE_RUNNING 1
 #define THREAD_STATE_BLOCKED 2
 
+typedef unsigned long state_t;
+
 struct _proc_t;
 
 typedef struct _thread_t{
 	struct _thread_t* next;
+	struct _thread_t* prev;
 	struct _proc_t* proc;
 	arch_regs* regs;
-	size_t state;
+	state_t state;
 	void* kernelstack;
+	void* kernelstackbase;
+	size_t stacksize;
+	pid_t tid;
+	int priority;
 } thread_t;
 
 typedef struct _proc_t{
@@ -26,8 +37,19 @@ typedef struct _proc_t{
 	pid_t pid;
 	gid_t gid;
 	uid_t uid;
+	thread_t** threads;
+	size_t threadcount;
 	dirnode_t* root;
 	dirnode_t* cwd;
 } proc_t;
 
+
+typedef struct{
+	thread_t* start;
+	thread_t* end;
+	int lock;
+} sched_queue;
+
+void sched_init();
+
 #endif

src/include/kernel/timer.h

@@ -1,6 +1,7 @@
 #ifndef _TIMER_H_INCLUDE
 #define _TIMER_H_INCLUDE
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <arch/regs.h>
 
@@ -14,7 +15,7 @@ typedef struct _timer_req{
 } timer_req;
 
 void timer_init();
-void timer_add(timer_req* req, size_t us);
+void timer_add(timer_req* req, size_t us, bool start);
 void timer_resume();
 void timer_stop();
 void timer_irq(arch_regs* ctx);

src/include/stdio/vprintf.c

@@ -11,7 +11,6 @@
 
 typedef int wint_t;
 
-bool ignoresign = false;
 
 char* __int_str(uintmax_t i, char b[], int base, bool plusSignIfNeeded, bool spaceSignIfNeeded,
                 int paddingNo, bool justify, bool zeroPad) {
@@ -262,10 +261,8 @@ int vprintf (const char* format, va_list list)
                         {
 
                             size_t integer = va_arg(list, size_t);
-                        ignoresign = true;
 			__int_str(integer, intStrBuffer, base, plusSign, spaceNoSign, lengthSpec, leftJustify, zeroPad);
                             displayString(intStrBuffer, &chars);
-                            ignoresign = false;
 			    break;
                         }
                         case 't':

src/sys/sched/scheduler.c

@@ -1,20 +1,111 @@
 #include <kernel/sched.h>
 #include <arch/cls.h>
+#include <kernel/sched.h>
+#include <arch/spinlock.h>
+#include <kernel/alloc.h>
+#include <arch/mmu.h>
+#include <kernel/pmm.h>
+#include <kernel/timer.h>
 
-thread_t* queue;
+#define THREAD_QUANTUM 10000
-thread_t* blocked;
 
-static thread_t* next_thread(){
+// queue 0: interrupt threads
+// queue 1: kernel threads
+// queue 2: user threads
 
-	thread_t* thread = queue;
+#define QUEUE_COUNT 3
 
-	while(1){
+sched_queue queues[QUEUE_COUNT];
+sched_queue running;
+sched_queue blocked;
 
-		while(thread != NULL && thread->state != THREAD_STATE_WAITING)
+static thread_t* allocthread(proc_t* proc, state_t state, pid_t tid, size_t kstacksize){
-			thread = thread->next;
 	
-		if(!thread)
+	thread_t* thread = alloc(sizeof(thread_t));
-			asm("hlt"); // wait until something happens that would allow a thread to be scheduled
+	if(!thread)
+		return NULL;
+
+
+	thread->regs = alloc(sizeof(arch_regs));
+	
+	if(!thread->regs){
+		free(thread);
+		return NULL;
+	}
+
+
+	// XXX use alloc() when it's better
+	
+	size_t pagec = kstacksize / PAGE_SIZE + 1;
+	
+	thread->kernelstackbase = pmm_hhdmalloc(pagec);
+
+
+	if(!thread->kernelstackbase){
+		free(thread->regs);
+		free(thread);
+		return NULL;
+	}
+
+	thread->proc = proc;
+	thread->state = state;
+	thread->tid = tid;
+	thread->kernelstack = thread->kernelstackbase + kstacksize;
+	thread->stacksize = kstacksize;
+	
+	return thread;
+
+}
+
+static void queue_add(sched_queue* queue, thread_t* thread){
+	thread->next = NULL;
+	thread->prev = queue->end;
+	if(queue->end)
+		queue->end->next = thread;
+	queue->end = thread;
+	if(!queue->start)
+		queue->start = thread;
+
+}
+
+static void queue_remove(sched_queue* queue, thread_t* thread){	
+
+	if(thread->next)
+		thread->next->prev = thread->prev;
+	else
+		queue->end = thread->prev;
+
+	if(thread->prev)
+		thread->prev->next = thread->next;
+	else
+		queue->start = thread->next;
+
+}
+
+static thread_t* getnext(){
+	
+	thread_t* thread = NULL;
+
+	for(int i = 0; i < QUEUE_COUNT && thread == NULL; ++i){
+		
+		spinlock_acquire(&queues[i].lock);
+		
+		if(queues[i].start){
+			thread = queues[i].start;
+			queue_remove(&queues[i], thread);
+		}
+
+		spinlock_release(&queues[i].lock);
+
+	}
+
+	if(thread){
+
+		spinlock_acquire(&running.lock);
+		
+		queue_add(&running, thread);
+		
+		spinlock_release(&running.lock);
 
 	}
 
@@ -22,28 +113,85 @@ static thread_t* next_thread(){
 
 }
 
-__attribute__((noreturn)) static void sched_switch(thread_t* thread){
+int a = 0;
+
+void sched_timerhook(arch_regs* regs){
 
 	thread_t* current = arch_getcls()->thread;
 
+	sched_queue* currentqueue = &queues[current->priority];
+
+
+	spinlock_acquire(&running.lock);
+
+	queue_remove(&running, current);
+
+	spinlock_release(&running.lock);
+
+
+	memcpy(current->regs, regs, sizeof(arch_regs));
+
+
+	spinlock_acquire(&currentqueue->lock);
+
+	queue_add(currentqueue, current);
+
+	spinlock_release(&currentqueue->lock);
+	
+
+	thread_t* next = getnext();
+	
+	if(next)
+		memcpy(regs, next->regs, sizeof(arch_regs));
+
+	timer_add(&arch_getcls()->schedreq, THREAD_QUANTUM, false);
+
+	arch_getcls()->thread = next;
+
+}
+
+static void switch_thread(thread_t* thread){
+	
+	thread_t* current = arch_getcls()->thread;
+	
+	// if we don't have to change processes don't waste time
+	
 	if(current->proc != thread->proc){
 		
-		// change address spaces and all
+		// TODO change proc specific stuff
 
 	}
 
+	arch_setkernelstack(thread->kernelstack);
+
 	arch_switchcontext(thread->regs);
 	
 	__builtin_unreachable();
+
 }
 
-__attribute__((noreturn)) void sched_timerhook(arch_regs* c){
+thread_t* sched_newkthread(void* ip, size_t stacksize, bool run, int prio){
+	thread_t* thread = allocthread(NULL, THREAD_STATE_WAITING, 0, stacksize);
 
-	thread_t* current = arch_getcls()->thread;
+	if(!thread) return NULL;
 	
-	memcpy(current->regs, c, sizeof(arch_regs));
+	thread->priority = prio;
 
-	;
+	arch_regs_setupkernel(thread->regs, ip, thread->kernelstack, true);
 
-	__builtin_unreachable();
+	if(run)
+		queue_add(&queues[prio], thread);
+
+	return thread;
 }
+
+void sched_init(){
+	arch_getcls()->thread = allocthread(NULL, THREAD_STATE_RUNNING, 0, 0);
+	arch_getcls()->thread->priority = THREAD_PRIORITY_KERNEL;
+
+	timer_req* req = &arch_getcls()->schedreq;
+
+	req->func = sched_timerhook;
+
+}
+

src/sys/timer.c

@@ -43,7 +43,7 @@ void timer_stop(){
 	}
 }
 
-void timer_add(timer_req* req, size_t us){
+void timer_add(timer_req* req, size_t us, bool start){
 	
 	size_t remainingticks = arch_cputimer_stop();
 
@@ -55,8 +55,8 @@ void timer_add(timer_req* req, size_t us){
 	if(!iter){
 		arch_getcls()->timerfirstreq = req;
 		req->next = NULL;
-		arch_cputimer_fire(req->ticks);
+		if(start);
-		printf("ticks3: %lu", req->ticks);
+			arch_cputimer_fire(req->ticks);
 		return;
 	}
 	
@@ -72,8 +72,8 @@ void timer_add(timer_req* req, size_t us){
 	if(iter->ticks > req->ticks){
 		req->next = arch_getcls()->timerfirstreq;
 		arch_getcls()->timerfirstreq = req;
-		arch_cputimer_fire(req->ticks);
+		if(start)
-		printf("ticks2: %lu", req->ticks);
+			arch_cputimer_fire(req->ticks);
 		return;
 	}
 
@@ -83,7 +83,7 @@ void timer_add(timer_req* req, size_t us){
 	req->next = iter->next;
 	iter->next = req;
 
-	printf("ticks: %lu", arch_getcls()->timerfirstreq->ticks);
+	if(start)
-	arch_cputimer_fire(arch_getcls()->timerfirstreq->ticks);
+		arch_cputimer_fire(arch_getcls()->timerfirstreq->ticks);
 	
 }