From 0d80865f669c2314c905f94a4117300a33338792 Mon Sep 17 00:00:00 2001
From: Christian Cunningham <cc@localhost>
Date: Wed, 2 Mar 2022 22:28:41 -0700
Subject: Remove old scheduling

---
 later/schedule.S | 143 -----------------------------------------------
 later/schedule.c | 167 -------------------------------------------------------
 later/schedule.h | 144 -----------------------------------------------
 3 files changed, 454 deletions(-)
 delete mode 100644 later/schedule.S
 delete mode 100644 later/schedule.c
 delete mode 100644 later/schedule.h

(limited to 'later')

diff --git a/later/schedule.S b/later/schedule.S
deleted file mode 100644
index a46654c..0000000
--- a/later/schedule.S
+++ /dev/null
@@ -1,143 +0,0 @@
-.section ".text"
-.globl schedule
-// TODO: Implement Scheduler for IRQ
-
-
-// Save Context
-// reg = struct cpu_context*
-.macro save_context reg
-	str r4,  [\reg, #0x00]
-	str r5,  [\reg, #0x04]
-	str r6,  [\reg, #0x08]
-	str r7,  [\reg, #0x0c]
-	str r8,  [\reg, #0x10]
-	str r9,  [\reg, #0x14]
-	str r10, [\reg, #0x18]
-	str r11, [\reg, #0x1c]
-	str r12, [\reg, #0x20]
-	str lr,  [\reg, #0x24]
-.endm
-// Restore Context
-// reg = struct cpu_context*
-.macro restore_context reg
-	ldr r4, [\reg, #0x00]
-	ldr r5, [\reg, #0x04]
-	ldr r6, [\reg, #0x08]
-	ldr r7, [\reg, #0x0c]
-	ldr r8, [\reg, #0x10]
-	ldr r9, [\reg, #0x14]
-	ldr r10, [\reg, #0x18]
-	ldr r11, [\reg, #0x1c]
-	ldr r12, [\reg, #0x20]
-	ldr lr , [\reg, #0x24]
-.endm
-
-// Implemented the scheduler in Assembly since the C defined was messing around with the program stacks
-//  This way, I can be confident that the stacks will be unchanged
-schedule:
-	ldr r3, =scheduler
-	// Preserve context
-	ldr r0, [r3, #4]
-	// r0 = struct cpu_context*
-	save_context r0
-	// Get the next available thread
-	push {r1-r3, lr}
-	bl get_next_thread
-	pop {r1-r3, lr}
-	ldr r1,  [r3, #0] 
-	// r3 = struct Scheduler*
-	// r0 = struct LL* next_thread_ll
-	// r1 = struct LL* current_thread_ll
-	// Check if there is a valid currently running thread
-	cmp r1, #0
-	beq schedule.current_thread_nexists
-schedule.current_thread_exists:
-	cmp r0, r1
-	beq schedule.run_current
-	cmp r0, #0
-	moveq r0, r1 // Make the current running thread the next running thread if no next running thread
-	// Next is not the same as the current
-	// Preserve stack of current
-	ldr r2,  [r1, #0x8] // struct Thread* current
-	ldrh r1, [r2, #0x0e]
-	cmp r1, #2 // THREAD_WAITING
-	beq schedule.temp_status
-	cmp r1, #1 // THREAD_RUNNING
-	bne schedule.dont_modify_status
-schedule.temp_status:
-	mov r1, #0 // THREAD_READY
-	strh r1, [r2, #0x0e]
-schedule.dont_modify_status:
-	str sp,  [r2, #0x4] // void* stack // Preserve stack
-	// Preserve program counter of current
-	str lr,  [r2, #0x0] // void* thread // Preserve pc
-	ldr r2,  [r0, #0x8] // struct Thread* next
-	// Set new stack pointer
-	ldr sp,  [r2, #0x4]
-	// Set the thread as running
-	mov r1, #1 // THREAD_RUNNING
-	strh r1,  [r2, #0x0e] // unsigned short status
-	add r2,  r2, #0x18
-	// Set new running thread
-	str r0,  [r3, #0x0] // struct LL* next_thread_ll // Set new running thread
-	// Set new context
-	str r2,  [r3, #0x4] // struct cpu_context* ctx // Set new context
-	b schedule.run_current
-schedule.current_thread_nexists:
-	// r0 = struct LL* next_thread_ll
-	// r1 = 0 = struct LL* current_thread_ll
-	cmp r0, #0
-	beq schedule.no_next_thread
-	ldr r1, [r0, #0x8]
-	// r1 =  struct Thread* next_thread
-	// Store system stack pointer
-	ldr r2, =svcsp
-	push {r1}
-	ldr r1, [r2]
-	cmp r1, #0
-	pop {r1}
-	bne schedule.dont_overwrite_sys_stack
-	// Store if zero system stack
-	str sp, [r2]
-schedule.dont_overwrite_sys_stack:
-	// Move stack to next thread's stack pointer
-	ldr sp, [r1, #0x4] // void* stack
-	// Store the running thread ll entry
-	str r0, [r3, #0x0] // struct LL* rthread_ll
-	ldr r2, [r0, #0x8] // struct Thread* thread
-	mov r0, #1 // THREAD_RUNNING
-	strh r0, [r2, #0x0e]
-	// Set context
-	add r1, r1, #0x18 // struct cpu_context*
-	str r1, [r3, #0x4] // store to scheduler.ctx
-schedule.run_current:
-	// Restore context
-	ldr r2,  [r3, #0x4] // struct cpu_context* ctx // Set new context
-	restore_context r2
-	// Run
-	ldr r1, [r3, #0]
-	// r1 = struct LL* rthread_ll
-	ldr r1, [r1, #0x8]
-	// r1 = struct Thread* rthread
-	ldr r0, [r1, #0x0]
-	// r0 = void* thread
-	bx r0
-schedule.no_next_thread:
-	// r0 = 0 = struct LL* next_thread_ll
-	// r1 = 0 = struct LL* current_thread_ll
-	// No thread to run
-	// Restore sys context
-	ldr r0, =svccpu
-	str r0, [r3, #0x4] // Store context
-	ldr r0, =svcsp
-	ldr r1, [r0]
-	cmp r1, #0
-	beq schedule.exit
-	mov sp, r1 // Restore stack pointer
-	mov r1, #0
-	str r1, [r0] // Clear stack pointer
-schedule.exit:
-	// Restore register context
-	ldr r2,  [r3, #0x4] // struct cpu_context* ctx // Set new context
-	restore_context r2
-	bx lr
diff --git a/later/schedule.c b/later/schedule.c
deleted file mode 100644
index c300ae0..0000000
--- a/later/schedule.c
+++ /dev/null
@@ -1,167 +0,0 @@
-#include <cpu/irq.h>
-#include <drivers/uart.h>
-#include <globals.h>
-#include <sys/core.h>
-#include <sys/schedule.h>
-#include <util/mutex.h>
-
-void init_scheduler(void)
-{
-	for(int i = 0; i < PRIORITIES; i++) {
-		scheduler.tlist[i].prev = &scheduler.tlist[i];
-		scheduler.tlist[i].next = &scheduler.tlist[i];
-		scheduler.tlist[i].data = 0;
-	}
-	scheduler.rthread_ll = 0;
-	scheduler.ctx = &svccpu;
-}
-
-void* get_stack(void)
-{
-	for (int i = 0; i < MAX_THREADS; i++) {
-		if (stacks_table[i] == 0) {
-			stacks_table[i] = 1;
-			return (void*)heap_end() - STACK_SIZE*i;
-		}
-	}
-	return 0;
-}
-
-void add_thread(void (*thread_fxn)(void), unsigned char priority)
-{
-	struct Thread* thread = (struct Thread*)malloca(sizeof(struct Thread), 4);
-	// Set the program counter to the entry
-	thread->thread = thread_fxn;
-	// Get a stack frame
-	thread->stack_base = get_stack();
-	thread->stack = thread->stack_base;
-	// Put in error state for no stack
-	if(thread->stack == 0)
-		thread->data.status = THREAD_STACK_ERROR;
-	else
-		thread->data.status = THREAD_READY;
-	// Doesn't wait for mutex at start
-	thread->data.mutex_waiting = 0;
-	// Set PID
-	thread->data.pid = nextpid++;
-	thread->data.preempt_count = 0;
-	thread->data.cpu_context.lr = (unsigned long)cleanup;
-	unsigned char p = priority;
-	if (p >= PRIORITIES) {
-		p = PRIORITIES - 1;
-	}
-	thread->data.priority = p;
-	push_ll(&scheduler.tlist[p], thread);
-}
-
-struct LL* get_next_thread(void)
-{
-	for(unsigned long i = 0; i < PRIORITIES; i++) {
-		struct LL* thread_ll = scheduler.tlist[i].next;
-		if (thread_ll == &scheduler.tlist[i])
-			continue;
-		do {
-			struct Thread* thread = thread_ll->data;
-			if((thread->data.status == THREAD_RUNNING) || (thread->data.status == THREAD_READY))
-				return thread_ll;
-			thread_ll = thread_ll->next;
-		} while(thread_ll != &scheduler.tlist[i]);
-	}
-	return 0;
-}
-
-void schedule_c(void)
-{
-	// Preserve registers in current context
-	preserve_ctx(scheduler.ctx);
-
-	// Get current thread
-	struct LL* current_thread_ll = scheduler.rthread_ll;
-	// Get next thread
-	struct LL* next_thread_ll = get_next_thread();
-
-	// If there is a current thread
-	if (current_thread_ll != 0) {
-		// If we are switching the thread
-		if (current_thread_ll != next_thread_ll) {
-			// Context switch
-			struct Thread* current_thread = current_thread_ll->data;
-			struct Thread* next_thread = next_thread_ll->data;
-			preserve_stack(current_thread);
-			//preserve_pc(current_thread);
-			current_thread->thread = (void*)current_thread->data.cpu_context.lr;
-			restore_stack(next_thread);
-			scheduler.rthread_ll = next_thread_ll;
-			scheduler.ctx = &next_thread->data.cpu_context;
-		}
-	}
-	else if (next_thread_ll != 0) {
-		struct Thread* next_thread = next_thread_ll->data;
-		preserve_sys_stack(&svcsp);
-		restore_stack(next_thread);
-		scheduler.rthread_ll = next_thread_ll;
-		scheduler.ctx = &next_thread->data.cpu_context;
-	}
-	if (scheduler.rthread_ll) {
-		struct Thread* rthread = scheduler.rthread_ll->data;
-		restore_ctx(scheduler.ctx);
-		asm volatile ("bx %0" :: "r"(rthread->thread));
-	} else {
-		scheduler.ctx = &svccpu;
-		restore_sys_stack(&svcsp);
-		restore_ctx(scheduler.ctx);
-	}
-}
-
-void cleanup(void)
-{
-	if (scheduler.rthread_ll != 0) {
-		// Mark the thread as finished
-		struct Thread* t = scheduler.rthread_ll->data;
-		//uart_string("Cleaning up thread ");
-		//uart_10(t->data.pid);
-		//uart_char('\n');
-		t->data.status = THREAD_FINISHED;
-		// Mark the stack space as free
-		unsigned long sidx = (unsigned long)(heap_end() - t->stack_base)/STACK_SIZE;
-		stacks_table[sidx] = 0;
-		// Remove the thread
-		struct LL* ll = scheduler.rthread_ll;
-		struct LL* prev = ll->prev;
-		struct LL* next = ll->next;
-		prev->next = ll->next;
-		next->prev = ll->prev;
-		free(ll->data);
-		free(ll);
-		scheduler.rthread_ll = 0;
-	}
-	// Schedule next thread
-	schedule();
-}
-
-void sched_info(void)
-{
-	uart_string("Scheduler Information\n");
-	for(unsigned long i = 0; i < PRIORITIES; i++) {
-		struct LL* ll = scheduler.tlist[i].next;
-		uart_string("Queue ");
-		uart_10(i);
-		while (ll != &scheduler.tlist[i]) {
-			uart_string("\nThread ");
-			struct Thread* t = ll->data;
-			uart_hex((unsigned long)t->thread);uart_char(' ');
-			uart_hex((unsigned long)t->stack);uart_char(' ');
-			uart_hex((unsigned long)t->stack_base);uart_char(' ');
-			uart_10(t->data.priority);uart_char(' ');
-			uart_10(t->data.preempt_count);uart_char(' ');
-			uart_10(t->data.status);uart_char(' ');
-			uart_hex((unsigned long)t->data.mutex_waiting);uart_char(' ');
-			uart_10(t->data.pid);uart_char('\n');
-			memshow32((unsigned long*)&t->data.cpu_context, 10);
-			ll = ll->next;
-		}
-		uart_char('\n');
-	}
-	uart_string("Stacks:\n");
-	memshow32((unsigned long*)stacks_table, 6);
-}
diff --git a/later/schedule.h b/later/schedule.h
deleted file mode 100644
index e1cde57..0000000
--- a/later/schedule.h
+++ /dev/null
@@ -1,144 +0,0 @@
-#ifndef SYS_SCHEDULE_H
-#define SYS_SCHEDULE_H
-#include <cpu.h>
-#include <lib/mem.h>
-#include <lib/ll.h>
-#include <sys/core.h>
-
-enum ThreadStatus {
-	THREAD_READY = 0,
-	THREAD_RUNNING = 1,
-	THREAD_WAITING = 2,
-	THREAD_WAITING_FOR_MUTEX = 3,
-	THREAD_FINISHED = 4,
-	THREAD_STACK_ERROR = 5,
-};
-
-struct cpu_context {
-	unsigned long r4;
-	unsigned long r5;
-	unsigned long r6;
-	unsigned long r7;
-	unsigned long r8;
-	unsigned long r9;
-	unsigned long r10;
-	unsigned long r11;
-	unsigned long r12;
-	unsigned long lr;
-};
-
-struct ThreadData {
-	unsigned char priority;
-	unsigned char preempt_count;
-	unsigned short status;
-	void* mutex_waiting;
-	unsigned long pid;
-	struct cpu_context cpu_context;
-};
-
-struct Thread {
-	//void (*thread)(void);
-	void* thread;
-	void* stack;
-	void* stack_base;
-	struct ThreadData data;
-};
-
-#define MAX_THREADS 0x100
-#define STACK_SIZE 0x1000
-#define PRIORITIES 6
-struct Scheduler {
-	struct LL* rthread_ll;
-	struct cpu_context* ctx;
-	struct LL tlist[PRIORITIES];
-};
-
-void init_scheduler(void);
-void add_thread(void (*thread_fxn)(void), unsigned char priority);
-extern void schedule(void);
-void schedule_c(void);
-void schedule_irq(void);
-void cleanup(void);
-void sched_info(void);
-struct LL* get_next_thread(void);
-
-static inline void preserve_stack(struct Thread* thread)
-{
-	// Get current mode
-	unsigned long mode = getmode();
-	// Set supervisor mode - "User mode"
-	setsvc();
-	// Store the stack pointer
-	void* ssp = getsp() + 4*4; // Ignore 4 words pushed on by (schedule)
-	thread->stack = ssp;
-	// Restore mode
-	setmode(mode);
-}
-
-static inline void restore_stack(struct Thread* thread)
-{
-	// Get current mode
-	unsigned long mode = getmode();
-	// Set supervisor mode - "User mode"
-	setsvc();
-	// Set stack pointer to thread's stack pointer
-	asm volatile("mov sp, %0" :: "r"(thread->stack));
-	// Restore mode
-	setmode(mode);
-}
-
-static inline void preserve_sys_stack(unsigned long* sp)
-{
-	if (*sp == 0) {
-		unsigned long mode = getmode();
-		setsvc();
-		*sp = (unsigned long)getsp();
-		setmode(mode);
-	}
-}
-
-static inline void restore_sys_stack(unsigned long* sp)
-{
-	if (*sp) {
-		unsigned long mode = getmode();
-		setsvc();
-		setsp((void*)*sp);
-		setmode(mode);
-		*sp = 0;
-	}
-}
-
-static inline void preserve_pc(struct Thread* t)
-{
-	t->thread = (void*)t->data.cpu_context.lr;
-}
-
-static inline void preserve_ctx(struct cpu_context* cpuctx)
-{
-	asm volatile ("mov %0, r4" : "=r"(cpuctx->r4));
-	asm volatile ("mov %0, r5" : "=r"(cpuctx->r5));
-	asm volatile ("mov %0, r6" : "=r"(cpuctx->r6));
-	asm volatile ("mov %0, r7" : "=r"(cpuctx->r7));
-	asm volatile ("mov %0, r8" : "=r"(cpuctx->r8));
-	asm volatile ("mov %0, r9" : "=r"(cpuctx->r9));
-	asm volatile ("mov %0, r10" : "=r"(cpuctx->r10));
-	asm volatile ("mov %0, r11" : "=r"(cpuctx->r11));
-	asm volatile ("mov %0, r12" : "=r"(cpuctx->r12));
-	asm volatile ("mov %0, lr" : "=r"(cpuctx->lr));
-}
-
-static inline void restore_ctx(struct cpu_context* cpuctx)
-{
-	asm volatile ("mov r4,  %0" :: "r"(cpuctx->r4));
-	asm volatile ("mov r5,  %0" :: "r"(cpuctx->r5));
-	asm volatile ("mov r6,  %0" :: "r"(cpuctx->r6));
-	asm volatile ("mov r7,  %0" :: "r"(cpuctx->r7));
-	asm volatile ("mov r8,  %0" :: "r"(cpuctx->r8));
-	asm volatile ("mov r9,  %0" :: "r"(cpuctx->r9));
-	asm volatile ("mov r10, %0" :: "r"(cpuctx->r10));
-	asm volatile ("mov r11, %0" :: "r"(cpuctx->r11));
-	asm volatile ("mov r12, %0" :: "r"(cpuctx->r12));
-	asm volatile ("mov lr,  %0" :: "r"(cpuctx->lr));
-}
-
-#endif
-- 
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