#include <stddef.h>
#include "debug.h"
#include "interrupt.h"
+#include "intr-stubs.h"
#include "lib.h"
#include "mmu.h"
#include "palloc.h"
#include "random.h"
+#include "switch.h"
uint32_t thread_stack_ofs = offsetof (struct thread, stack);
static struct list run_queue;
+static struct thread *idle_thread;
-struct thread *thread_switch (struct thread *cur, struct thread *next);
+static void
+idle (void *aux UNUSED)
+{
+ for (;;)
+ {
+ /* Wait for an interrupt. */
+ asm ("hlt");
+
+ /* Let someone else run. */
+ intr_disable ();
+ thread_sleep ();
+ intr_enable ();
+ }
+}
void
-thread_init (void)
+thread_init (const char *name, void (*function) (void *aux), void *aux)
{
+ struct thread *initial_thread;
+
+ ASSERT (intr_get_level () == IF_OFF);
+
list_init (&run_queue);
+ idle_thread = thread_create ("idle", idle, NULL);
+
+ initial_thread = thread_create (name, function, aux);
+ list_remove (&initial_thread->rq_elem);
+ initial_thread->status = THREAD_RUNNING;
+ switch_threads (NULL, initial_thread);
+
+ NOT_REACHED ();
}
+struct kernel_thread_frame
+ {
+ void *eip; /* Return address. */
+ void (*function) (void *); /* Function to call. */
+ void *aux; /* Auxiliary data for function. */
+ };
+
static void
-thread_root (void (*function) (void *aux), void *aux)
+kernel_thread (void (*function) (void *aux), void *aux)
{
ASSERT (function != NULL);
-
+
+ intr_enable ();
function (aux);
thread_exit ();
}
+static struct thread *
+new_thread (const char *name)
+{
+ struct thread *t;
+
+ ASSERT (name != NULL);
+
+ t = palloc_get (PAL_ZERO);
+ if (t != NULL)
+ {
+ strlcpy (t->name, name, sizeof t->name);
+ t->stack = (uint8_t *) t + PGSIZE;
+ t->status = THREAD_BLOCKED;
+ }
+
+ return t;
+}
+
+static void *
+alloc_frame (struct thread *t, size_t size)
+{
+ ASSERT (size % sizeof (uint32_t) == 0);
+
+ t->stack -= size;
+ return t->stack;
+}
+
struct thread *
thread_create (const char *name, void (*function) (void *aux), void *aux)
{
struct thread *t;
+ struct kernel_thread_frame *kf;
+ struct switch_entry_frame *ef;
+ struct switch_threads_frame *sf;
- ASSERT (name != NULL);
ASSERT (function != NULL);
- t = palloc_get (0);
- if (t == NULL)
- return NULL;
+ t = new_thread (name);
- memset (t, 0, PGSIZE);
- strlcpy (t->name, name, sizeof t->name);
+ /* Stack frame for kernel_thread(). */
+ kf = alloc_frame (t, sizeof *kf);
+ kf->eip = NULL;
+ kf->function = function;
+ kf->aux = aux;
- /* Set up stack. */
- t->stack = (uint32_t *) ((uint8_t *) t + PGSIZE);
- *--t->stack = (uint32_t) aux;
- *--t->stack = (uint32_t) function;
- --t->stack;
- *--t->stack = (uint32_t) thread_root;
- t->stack -= 4;
+ /* Stack frame for switch_entry(). */
+ ef = alloc_frame (t, sizeof *ef);
+ ef->eip = (void (*) (void)) kernel_thread;
- /* Add to run_queue. */
- t->status = THREAD_BLOCKED;
+ /* Stack frame for thread_switch(). */
+ sf = alloc_frame (t, sizeof *sf);
+ sf->eip = switch_entry;
+
+ /* Add to run queue. */
thread_ready (t);
return t;
}
-static struct thread *
-stack_to_thread (uint32_t *stack)
-{
- return (struct thread *) ((uint32_t) (stack - 1) & ~((uint32_t) PGSIZE - 1));
-}
-
struct thread *
thread_current (void)
{
uint32_t *esp;
asm ("movl %%esp, %0\n" : "=g" (esp));
- return stack_to_thread (esp);
+ return pg_round_down (esp);
}
#ifdef USERPROG
-void
+bool
thread_execute (const char *filename)
{
- struct thread *t = thread_current ();
+ struct thread *t;
+ struct intr_frame *if_;
+ struct switch_entry_frame *ef;
+ struct switch_threads_frame *sf;
+ void (*start) (void);
+
+ ASSERT (filename != NULL);
+
+ t = new_thread (filename);
+ if (t == NULL)
+ return false;
- if (!addrspace_load (&t->addrspace, filename))
+ if (!addrspace_load (&t->addrspace, filename, &start))
panic ("%s: program load failed", filename);
- panic ("%s: loaded", filename);
+
+ /* Interrupt frame. */
+ if_ = alloc_frame (t, sizeof *if_);
+ if_->es = SEL_UDSEG;
+ if_->ds = SEL_UDSEG;
+ if_->eip = start;
+ if_->cs = SEL_UCSEG;
+ if_->eflags = FLAG_IF | 2;
+ if_->esp = PHYS_BASE;
+ if_->ss = SEL_UDSEG;
+
+ /* Stack frame for switch_entry(). */
+ ef = alloc_frame (t, sizeof *ef);
+ ef->eip = intr_exit;
+
+ /* Stack frame for thread_switch(). */
+ sf = alloc_frame (t, sizeof *sf);
+ sf->eip = switch_entry;
+
+ /* Add to run queue. */
+ thread_ready (t);
+
+ return true;
}
#endif
return list_entry (list_pop_front (&run_queue), struct thread, rq_elem);
}
-static void
-idle (void)
-{
- static int idle = 0;
- if (idle++ == 0)
- printk ("idle\n");
-}
-
void
thread_destroy (struct thread *t)
{
palloc_free (t);
}
+void schedule_tail (struct thread *prev);
+
void
+schedule_tail (struct thread *prev)
+{
+ ASSERT (intr_get_level () == IF_OFF);
+
+#ifdef USERPROG
+ addrspace_activate (&thread_current ()->addrspace);
+#endif
+
+ if (prev != NULL && prev->status == THREAD_DYING)
+ thread_destroy (prev);
+}
+
+static void
thread_schedule (void)
{
struct thread *cur, *next, *prev;
cur = thread_current ();
ASSERT (cur->status != THREAD_RUNNING);
- while ((next = find_next_to_run ()) == NULL)
- idle ();
+ next = find_next_to_run ();
+ if (next == NULL)
+ next = idle_thread;
next->status = THREAD_RUNNING;
- prev = thread_switch (cur, next);
+ if (cur != next)
+ {
+ prev = switch_threads (cur, next);
- /* Prevent GCC from reordering anything around the thread
- switch. */
- asm volatile ("" : : : "memory");
+ /* Prevent GCC from reordering anything around the thread
+ switch. */
+ asm volatile ("" : : : "memory");
- if (prev != NULL && prev->status == THREAD_DYING)
- thread_destroy (prev);
-
- intr_enable ();
+ schedule_tail (prev);
+ }
}
void
thread_yield (void)
{
+ enum if_level old_level;
+
ASSERT (!intr_context ());
- intr_disable ();
+ old_level = intr_disable ();
thread_ready (thread_current ());
thread_schedule ();
-}
-
-void
-thread_start (struct thread *t)
-{
- ASSERT (intr_get_level () == IF_OFF);
-
- if (t->status == THREAD_READY)
- list_remove (&t->rq_elem);
- t->status = THREAD_RUNNING;
- thread_switch (NULL, t);
+ intr_set_level (old_level);
}
void
intr_disable ();
thread_current ()->status = THREAD_DYING;
thread_schedule ();
+ NOT_REACHED ();
}
void
thread_current ()->status = THREAD_BLOCKED;
thread_schedule ();
}
-
-static void
-tfunc (void *aux UNUSED)
-{
- for (;;)
- {
- size_t count, i;
- if (random_ulong () % 5 == 0)
- {
- printk ("%s exiting\n", thread_current ()->name);
- break;
- }
- count = random_ulong () % 25 * 10000;
- printk ("%s waiting %zu: ", thread_current ()->name, count);
- for (i = 0; i < count; i++);
- printk ("%s\n", thread_current ()->name);
- }
-}
-
-void
-thread_self_test (void)
-{
- struct thread *t;
- int i;
-
- for (i = 0; i < 4; i++)
- {
- char name[2];
- name[0] = 'a' + i;
- name[1] = 0;
- t = thread_create (name, tfunc, NULL);
- }
- thread_start (t);
-}
projects / pintos-anon / blobdiff