Scheduler and multiple threads

src/kernel/boot/TEMP-test_scheduler.c

@@ -0,0 +1,38 @@
+#include <framebuffer.h>
+#include <proc.h>
+#include <sched.h>
+
+extern gfx_context *term_fb;
+void drawCharacter(gfx_context *ctx, uint64_t x, uint64_t y, uint32_t clr_fg, uint32_t clr_bg, char c);
+
+
+
+void thread1()
+{
+    int a = 0;
+    while(1) {
+        drawCharacter(term_fb, 0, 0, RGB(255,0,0), RGB(0,0,0), '0'+(a++%10));
+        flip(term_fb);
+        sched_yield();
+    }
+}
+
+void thread2()
+{
+    int a = 0;
+    while(1) {
+        drawCharacter(term_fb, 10, 10, RGB(0,0,255), RGB(0,0,0), 'A'+(a++%10));
+        flip(term_fb);
+        sched_yield();
+    }
+}
+
+
+void TEMP_test_scheduler()
+{
+    struct thread *th1 = new_thread(thread1);
+    scheduler_insert(th1);
+
+    struct thread *th2 = new_thread(thread2);
+    scheduler_insert(th2);
+}

src/kernel/boot/kmain.c

@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <proc.h>
 
+void TEMP_test_scheduler();
 
 struct kernel_boot_data_st kernel_boot_data;
 
@@ -30,6 +31,10 @@ void kmain(uint64_t multiboot_magic, void *multiboot_data)
 
     debug_info("Boot complete\n");
 
+
+    TEMP_test_scheduler();
+
+
     start_scheduler();
 
     PANIC("End of kernel function!");

src/kernel/drivers/terminal/fbterm.c

@@ -105,7 +105,7 @@ char font[95][16] = {
 gfx_context *term_fb;
 static int setup = 0;
 
-static void drawCharacter(gfx_context *ctx, uint64_t x, uint64_t y, uint32_t clr_fg, uint32_t clr_bg, char c)
+void drawCharacter(gfx_context *ctx, uint64_t x, uint64_t y, uint32_t clr_fg, uint32_t clr_bg, char c)
 {
 
     char *chr = c ? font[(int)c-0x20]: font[0];

src/kernel/include/musl-glue.h

@@ -3,6 +3,7 @@
 #define SYSCALL_BRK 12
 #define SYSCALL_IOCTL 16
 #define SYSCALL_WRITEV 20
+#define SYSCALL_SCHED_YIELD 24
 
 typedef long (*syscall_handler)(long, long, long, long, long, long);
 
@@ -15,3 +16,6 @@ long k_writev(long fd, long iov, long iovcnt, long, long, long);
 
 // memory/kbrk.c
 long k_brk(long brk, long, long, long, long, long);
+
+// proc/scheduler.c
+long k_sched_yield(long, long, long, long, long, long);

src/kernel/include/proc.h

@@ -5,12 +5,21 @@ struct thread
 {
     struct thread *q_next;
     uint64_t tid;
-    void *stack;
+    void *stack_ptr;
     uint64_t state;
+    uint8_t stack[];
 };
 
+// proc/thread.c
+extern struct thread *current_thread;
+
 // proc/swtch.S
 void *switch_stack(void *out, void *in);
 
 // proc/thread.c
+struct thread *new_thread(void (*function)(void));
+struct thread *thread();
+
+// proc/scheduler.c
+void scheduler_insert(struct thread *new);
 void start_scheduler();

src/kernel/lib/musl-glue.c

@@ -2,9 +2,10 @@
 #include <debug.h>
 
 syscall_handler syscall_handlers[440] = {
-    [SYSCALL_BRK] = &k_brk,
-    [SYSCALL_IOCTL] = &k_ioctl,
-    [SYSCALL_WRITEV] = &k_writev,
+    [SYSCALL_BRK] = k_brk,
+    [SYSCALL_IOCTL] = k_ioctl,
+    [SYSCALL_WRITEV] = k_writev,
+    [SYSCALL_SCHED_YIELD] = k_sched_yield,
 };
 
 syscall_handler set_syscall_handler(long num, syscall_handler handler)

src/kernel/proc/scheduler.c

@@ -0,0 +1,57 @@
+#include <proc.h>
+
+static struct {
+    struct thread *first;
+    struct thread *last;
+} run_q = {0,0};
+
+static struct thread *scheduler_thread;
+
+static struct thread *scheduler_next()
+{
+    struct thread *ret = run_q.first;
+    if(run_q.first && !(run_q.first = run_q.first->q_next))
+        run_q.last = 0;
+    return ret;
+}
+
+void scheduler_insert(struct thread *new)
+{
+    if(run_q.last) {
+        run_q.last->q_next = new;
+        run_q.last = new;
+    } else {
+        run_q.first = run_q.last = new;
+    }
+    new->q_next = 0;
+}
+
+void scheduler()
+{
+    while(1)
+    {
+        struct thread *new = 0;
+        while(!(new = scheduler_next()));
+
+        current_thread = new;
+        switch_stack(&scheduler_thread->stack_ptr, &new->stack_ptr);
+
+        scheduler_insert(current_thread);
+        current_thread = 0;
+    }
+}
+
+long k_sched_yield(long, long, long, long, long, long)
+{
+    switch_stack(&current_thread->stack_ptr, &scheduler_thread->stack_ptr);
+    return 0;
+}
+
+void start_scheduler()
+{
+    scheduler_thread = new_thread(scheduler);
+    scheduler_thread->tid = (uint64_t)-1;
+
+    uint64_t stack;
+    switch_stack(&stack, &scheduler_thread->stack_ptr);
+}

src/kernel/proc/thread.c

@@ -16,18 +16,16 @@ struct swtch_stack
 
 static uint64_t next_tid = 1;
 
-static struct thread *run_queue = 0;
-static struct thread *current_thread;
-static struct thread *scheduler_thread;
+struct thread *current_thread;
 
 struct thread *new_thread(void (*function)(void))
 {
     struct thread *th = P2V(pmm_calloc());
     th->tid = next_tid++;
-    th->stack = incptr(th, PAGE_SIZE - sizeof(struct swtch_stack));
+    th->stack_ptr = incptr(th, PAGE_SIZE - sizeof(struct swtch_stack));
     th->q_next = 0;
 
-    struct swtch_stack *stck = th->stack;
+    struct swtch_stack *stck = th->stack_ptr;
     stck->RBP = (uint64_t)&stck->RBP2;
     stck->ret = (uint64_t)function;
 
@@ -38,37 +36,3 @@ struct thread *thread()
 {
     return current_thread;
 }
-
-void k_yield()
-{
-    switch_stack(&current_thread->stack, &scheduler_thread->stack);
-}
-
-struct thread *scheduler_next()
-{
-    if(!current_thread) return run_queue;
-    return current_thread->q_next;
-}
-
-void scheduler()
-{
-    while(1)
-    {
-        struct thread *new = 0;
-        while(!(new = scheduler_next()));
-
-        current_thread = new;
-        switch_stack(&scheduler_thread->stack, &new->stack);
-
-        current_thread = 0;
-    }
-}
-
-void start_scheduler()
-{
-    scheduler_thread = new_thread(scheduler);
-    scheduler_thread->tid = (uint64_t)-1;
-
-    uint64_t stack;
-    switch_stack(&stack, &scheduler_thread->stack);
-}