#include <round.h>
#include <stdio.h>
#include <string.h>
+#include "userprog/gdt.h"
#include "userprog/pagedir.h"
#include "userprog/tss.h"
#include "filesys/directory.h"
#include "filesys/file.h"
#include "filesys/filesys.h"
+#include "threads/flags.h"
#include "threads/init.h"
+#include "threads/interrupt.h"
#include "threads/mmu.h"
#include "threads/palloc.h"
#include "threads/thread.h"
+static thread_func execute_thread NO_RETURN;
+static bool load (const char *cmdline, void (**eip) (void), void **esp);
+
+/* Starts a new thread running a user program loaded from
+ FILENAME. The new thread may be scheduled before
+ addrspace_execute() returns.*/
+tid_t
+addrspace_execute (const char *filename)
+{
+ char *fn_copy;
+ tid_t tid;
+
+ /* Make a copy of FILENAME.
+ Otherwise there's a race between the caller and load(). */
+ fn_copy = palloc_get (0);
+ if (fn_copy == NULL)
+ return TID_ERROR;
+ strlcpy (fn_copy, filename, PGSIZE);
+
+ /* Create a new thread to execute FILENAME. */
+ tid = thread_create (filename, PRI_DEFAULT, execute_thread, fn_copy);
+ if (tid == TID_ERROR)
+ palloc_free (fn_copy);
+ return tid;
+}
+
+/* A thread function that loads a user process and starts it
+ running. */
+static void
+execute_thread (void *filename_)
+{
+ char *filename = filename_;
+ struct intr_frame if_;
+ bool success;
+
+ /* Initialize interrupt frame and load executable. */
+ memset (&if_, 0, sizeof if_);
+ if_.es = SEL_UDSEG;
+ if_.ds = SEL_UDSEG;
+ if_.cs = SEL_UCSEG;
+ if_.eflags = FLAG_IF | FLAG_MBS;
+ if_.ss = SEL_UDSEG;
+ success = load (filename, &if_.eip, &if_.esp);
+
+ /* If load failed, quit. */
+ palloc_free (filename);
+ if (!success)
+ thread_exit ();
+
+ /* Switch page tables. */
+ addrspace_activate ();
+
+ /* Start the user process by simulating a return from an
+ interrupt, implemented by intr_exit (in
+ threads/intr-stubs.pl). Because intr_exit takes all of its
+ arguments on the stack in the form of a `struct intr_frame',
+ we just point the stack pointer (%esp) to our stack frame
+ and jump to it. */
+ asm ("mov %0, %%esp\n"
+ "jmp intr_exit\n"
+ : /* no outputs */
+ : "g" (&if_));
+ NOT_REACHED ();
+}
+\f
/* We load ELF binaries. The following definitions are taken
from the ELF specification, [ELF1], more-or-less verbatim. */
#define PF_W 2 /* Writable. */
#define PF_R 4 /* Readable. */
-static bool load_segment (struct thread *, struct file *,
- const struct Elf32_Phdr *);
-static bool setup_stack (struct thread *, void **esp);
+static bool load_segment (struct file *, const struct Elf32_Phdr *);
+static bool setup_stack (void **esp);
/* Aborts loading an executable, with an error message. */
#define LOAD_ERROR(MSG) \
do { \
- printf ("addrspace_load: %s: ", filename); \
+ printf ("load: %s: ", filename); \
printf MSG; \
printf ("\n"); \
goto done; \
} while (0)
-/* Loads an ELF executable from FILENAME into T,
+/* Loads an ELF executable from FILENAME into the current thread.
Stores the executable's entry point into *EIP
and its initial stack pointer into *ESP.
Returns true if successful, false otherwise. */
bool
-addrspace_load (struct thread *t, const char *filename,
- void (**eip) (void), void **esp)
+load (const char *filename, void (**eip) (void), void **esp)
{
+ struct thread *t = thread_current ();
struct Elf32_Ehdr ehdr;
struct file *file = NULL;
off_t file_ofs;
printf ("unknown ELF segment type %08x\n", phdr.p_type);
break;
case PT_LOAD:
- if (!load_segment (t, file, &phdr))
+ if (!load_segment (file, &phdr))
goto done;
break;
}
}
/* Set up stack. */
- if (!setup_stack (t, esp))
+ if (!setup_stack (esp))
goto done;
/* Start address. */
success = true;
done:
- /* We arrive here whether the load is successful or not.
- We can distinguish based on `success'. */
+ /* We arrive here whether the load is successful or not. */
file_close (file);
- if (!success)
- addrspace_destroy (t);
return success;
}
void
addrspace_destroy (struct thread *t)
{
+ ASSERT (t != thread_current ());
+
if (t->pagedir != NULL)
{
pagedir_destroy (t->pagedir);
}
}
-/* Sets up the CPU for running user code in thread T, if any. */
+/* Sets up the CPU for running user code in the current
+ thread. */
void
-addrspace_activate (struct thread *t)
+addrspace_activate (void)
{
- ASSERT (t != NULL);
+ struct thread *t = thread_current ();
/* Activate T's page tables. */
pagedir_activate (t->pagedir);
\f
/* addrspace_load() helpers. */
-static bool install_page (struct thread *, void *upage, void *kpage);
+static bool install_page (void *upage, void *kpage);
-/* Loads the segment described by PHDR from FILE into thread T's
- user address space. Return true if successful, false
- otherwise. */
+/* Loads the segment described by PHDR from FILE into user
+ address space. Return true if successful, false otherwise. */
static bool
-load_segment (struct thread *t, struct file *file,
- const struct Elf32_Phdr *phdr)
+load_segment (struct file *file, const struct Elf32_Phdr *phdr)
{
void *start, *end; /* Page-rounded segment start and end. */
uint8_t *upage; /* Iterator from start to end. */
from swap. */
//bool read_only = (phdr->p_flags & PF_W) == 0;
- ASSERT (t != NULL);
ASSERT (file != NULL);
ASSERT (phdr != NULL);
ASSERT (phdr->p_type == PT_LOAD);
filesz_left -= read_bytes;
/* Add the page to the process's address space. */
- if (!install_page (t, upage, kpage))
+ if (!install_page (upage, kpage))
{
palloc_free (kpage);
return false;
return true;
}
-/* Create a minimal stack for T by mapping a zeroed page at the
- top of user virtual memory. */
+/* Create a minimal stack by mapping a zeroed page at the top of
+ user virtual memory. */
static bool
-setup_stack (struct thread *t, void **esp)
+setup_stack (void **esp)
{
uint8_t *kpage;
bool success = false;
kpage = palloc_get (PAL_USER | PAL_ZERO);
if (kpage != NULL)
{
- success = install_page (t, ((uint8_t *) PHYS_BASE) - PGSIZE, kpage);
+ success = install_page (((uint8_t *) PHYS_BASE) - PGSIZE, kpage);
if (success)
*esp = PHYS_BASE;
else
}
/* Adds a mapping from user virtual address UPAGE to kernel
- virtual address KPAGE to T's page tables. Fails if UPAGE is
+ virtual address KPAGE to the page table. Fails if UPAGE is
already mapped or if memory allocation fails. */
static bool
-install_page (struct thread *t, void *upage, void *kpage)
+install_page (void *upage, void *kpage)
{
+ struct thread *t = thread_current ();
+
/* Verify that there's not already a page at that virtual
address, then map our page there. */
return (pagedir_get_page (t->pagedir, upage) == NULL
projects / pintos-anon / blobdiff