diff options
author | Danny Holman <dholman@gymli.org> | 2024-03-28 22:00:16 -0500 |
---|---|---|
committer | Danny Holman <dholman@gymli.org> | 2024-03-28 22:00:16 -0500 |
commit | db684b8653d93f4a374d8d692bb0afb31db67987 (patch) | |
tree | 83dc7939470b4c9302538fbf220c7a02fc249a51 | |
parent | 3b66779d9a8325c77c6cfbf1565885f98da5378f (diff) |
kernel: add a basic thread scheduler
Add a basic thread scheduler. This should allow the kernel to schedule
threads according to the round robin algorithm.
Signed-off-by: Danny Holman <dholman@gymli.org>
-rw-r--r-- | Makefile | 1 | ||||
-rw-r--r-- | arch/i386/kernel/switch_thread.s | 28 | ||||
-rw-r--r-- | arch/i386/make.config | 2 | ||||
-rw-r--r-- | include/kernel/sched.h | 27 | ||||
-rw-r--r-- | kernel/sched.c | 64 |
5 files changed, 122 insertions, 0 deletions
@@ -29,6 +29,7 @@ KERNEL_OBJS=$(KERNEL_ARCH_OBJS) \ kernel/string.o \ kernel/io.o \ kernel/panic.o \ + kernel/sched.o \ OBJS=$(ARCHDIR)/boot/crti.o \ $(ARCHDIR)/crtbegin.o \ diff --git a/arch/i386/kernel/switch_thread.s b/arch/i386/kernel/switch_thread.s new file mode 100644 index 0000000..f1168d5 --- /dev/null +++ b/arch/i386/kernel/switch_thread.s @@ -0,0 +1,28 @@ +.global switch_thread +.type switch_thread, @function +switch_thread: + pushl %ebp + movl %esp, %ebp + + pushl %ebx + pushl %esi + pushl %edi + pushl %ebp + + movl 8(%ebp), %esi + movl 12(%ebp), %edi + + movl %esp, (%edi); + movl %cr3, %ecx + movl %ecx, 4(%edi) + + movl (%esi), %esp + movl 4(%esi), %ecx + movl %ecx, %cr3 + + popl %ebp + popl %edi + popl %esi + popl %ebx + popl %ebp + ret diff --git a/arch/i386/make.config b/arch/i386/make.config index 8499f1a..d4d98a7 100644 --- a/arch/i386/make.config +++ b/arch/i386/make.config @@ -17,3 +17,5 @@ KERNEL_ARCH_OBJS=$(ARCHDIR)/boot/boot.o \ $(ARCHDIR)/kernel/paging.o \ $(ARCHDIR)/kernel/pmem.o \ $(ARCHDIR)/kernel/kmalloc.o \ + $(ARCHDIR)/kernel/jump_userspace.o \ + $(ARCHDIR)/kernel/switch_thread.o \ diff --git a/include/kernel/sched.h b/include/kernel/sched.h new file mode 100644 index 0000000..fef36b8 --- /dev/null +++ b/include/kernel/sched.h @@ -0,0 +1,27 @@ +#ifndef KERNEL_SCHED_H +#define KERNEL_SCHED_H + +#include <kernel/asm.h> +#include <kernel/data/list.h> + +#define THREAD_READY 0 +#define THREAD_RUNNING 1 +#define THREAD_WAIT 2 + +struct task_block { + unsigned int pid; + unsigned int parent_pid; + int nice; + unsigned int num_threads; + struct thread_block *threads; + struct list_head list; +}; + +void sched_init(void); +void schedule_next(void); + +struct task_block* init_task(int nice, unsigned int ppid); +void schedule_thread(struct thread_block *thread); +void switch_thread(struct thread_block *old, struct thread_block *new); + +#endif diff --git a/kernel/sched.c b/kernel/sched.c new file mode 100644 index 0000000..8aab675 --- /dev/null +++ b/kernel/sched.c @@ -0,0 +1,64 @@ +#include <kernel/sched.h> +#include <kernel/container_of.h> +#include <kernel/data/list.h> +#include <kernel/string.h> +#include <kernel/kmalloc.h> +#include <stddef.h> + +static struct list_head *ready_queue; +static struct list_head *wait_queue; + +static struct task_block *cur = NULL; +static long int next_id = 1; + +static void _enqueue(struct list_head *queue, struct task_block *task) { + struct list_head *temp = queue; + while (temp->next != NULL) + temp = temp->next; + list_add(&task->list, temp); +} + +static struct task_block* _dequeue(struct list_head *queue) { + if (queue->next == NULL) + return NULL; + struct list_head *temp = queue->next; + list_del(temp); + struct task_block *ret = container_of(temp, struct task_block, list); + return ret; +} + +void sched_init(void) { + ready_queue = kmalloc(sizeof(struct list_head)); + wait_queue = kmalloc(sizeof(struct list_head)); + struct task_block *boot_task = init_task(0, 0); + boot_task->threads->state = THREAD_RUNNING; + cur = boot_task; + + switch_thread(boot_task->threads, boot_task->threads); +} + +void schedule_next(void) { + struct task_block *task = _dequeue(ready_queue); + if (task == NULL) + return; + if (cur != NULL) + _enqueue(ready_queue, cur); + disable_ints(); + switch_thread(cur->threads, task->threads); + enable_ints(); + task->threads->state = THREAD_RUNNING; + cur->threads->state = THREAD_READY; + cur = task; +} + +struct task_block* init_task(int nice, unsigned int ppid) { + struct task_block *ret = kmalloc(sizeof(struct task_block)); + ret->pid = next_id++; + ret->parent_pid = ppid; + ret->nice = nice; + ret->num_threads = 1; + ret->threads = kmalloc(sizeof(struct thread_block)); + ret->threads->tid = ret->pid; + ret->threads->tgid = ret->pid; + return ret; +} |