X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fthreads%2Finit.c;h=b099d02dd33ccbb8fb88889b821cde91ab772ad5;hb=97dcefb4742e13df9eb22c3aa00bb802bdc55c60;hp=8d354d43fdda51c5f9fbe2b0177f84b2e526f9f8;hpb=f09512e71e50d7be09249e7b87b270906ed8e499;p=pintos-anon

diff --git a/src/threads/init.c b/src/threads/init.c
index 8d354d4..b099d02 100644
--- a/src/threads/init.c
+++ b/src/threads/init.c
@@ -17,6 +17,11 @@
 #include "thread.h"
 #include "timer.h"
 #include "vga.h"
+#ifdef USERPROG
+#include "exception.h"
+#include "gdt.h"
+#include "tss.h"
+#endif
 #ifdef FILESYS
 #include "filesys.h"
 #include "disk.h"
@@ -37,30 +42,14 @@ static char *initial_program;
 #endif
 
 static void ram_init (void);
-static void gdt_init (void);
 static void argv_init (void);
 
-static void
-main_thread (void *aux UNUSED) 
-{
-#ifdef FILESYS
-  disk_init ();
-  filesys_init (format_filesys);
-  fsutil_run ();
-#endif
-
-#ifdef USERPROG
-  if (initial_program != NULL)
-    thread_execute (initial_program);
-  else
-    PANIC ("no initial program specified");
-#endif
-}
+int main (void) NO_RETURN;
 
 int
 main (void)
 {
-  /* Initialize prerequisites for calling printk(). */
+  /* Needed by printk(), so initialize them very early. */
   ram_init ();
   vga_init ();
   serial_init ();
@@ -71,101 +60,53 @@ main (void)
   /* Parse command line. */
   argv_init ();
 
-  /* Initialize memory system. */
+  /* Initialize memory system, segments, paging. */
+  thread_init ();
   palloc_init ();
   paging_init ();
+#ifdef USERPROG
+  tss_init ();
   gdt_init ();
+#endif
   malloc_init ();
 
+  /* Set random seed if not already done. */
   random_init (0);
 
   /* Initialize interrupt handlers. */
   intr_init ();
   timer_init ();
   kbd_init ();
+#ifdef USERPROG
+  exception_init ();
+#endif
 
-  /* Do everything else in a system thread. */
-  thread_init ();
-  thread_create ("main", main_thread, NULL);
+  /* Start thread scheduler and enable interrupts. */
   thread_start ();
-}
-
-static uint64_t
-make_seg_desc (uint32_t base,
-               uint32_t limit,
-               enum seg_system system,
-               enum seg_type type,
-               int dpl,
-               enum seg_granularity granularity)
-{
-  uint32_t e0 = ((limit & 0xffff)             /* Limit 15:0. */
-                 | (base << 16));             /* Base 15:0. */
-  uint32_t e1 = (((base >> 16) & 0xff)        /* Base 23:16. */
-                 | (system << 12)             /* 0=system, 1=code/data. */
-                 | (type << 8)                /* Segment type. */
-                 | (dpl << 13)                /* Descriptor privilege. */
-                 | (1 << 15)                  /* Present. */
-                 | (limit & 0xf0000)          /* Limit 16:19. */
-                 | (1 << 22)                  /* 32-bit segment. */
-                 | (granularity << 23)        /* Byte/page granularity. */
-                 | (base & 0xff000000));      /* Base 31:24. */
-  return e0 | ((uint64_t) e1 << 32);
-}
 
-static uint64_t
-make_code_desc (int dpl)
-{
-  return make_seg_desc (0, 0xfffff, SYS_CODE_DATA, TYPE_CODE | TYPE_READABLE,
-                        dpl, GRAN_PAGE);
-}
-
-static uint64_t
-make_data_desc (int dpl)
-{
-  return make_seg_desc (0, 0xfffff, SYS_CODE_DATA, TYPE_WRITABLE,
-                        dpl, GRAN_PAGE);
-}
-
-static uint64_t
-make_tss_desc (void *vaddr)
-{
-  return make_seg_desc ((uint32_t) vaddr,
-                        0x67, SYS_SYSTEM, TYPE_TSS_32_A, 0, GRAN_BYTE);
-}
+#ifdef FILESYS
+  /* Initialize filesystem. */
+  disk_init ();
+  filesys_init (format_filesys);
+  fsutil_run ();
+#endif
 
-static uint64_t gdt[SEL_CNT];
+  printk ("Boot complete.\n");
 
-struct tss *tss;
+#ifdef USERPROG
+  /* Run a user program. */
+  if (initial_program != NULL)
+    {
+      printk ("\nExecuting '%s':\n", initial_program);
+      thread_execute (initial_program); 
+    }
+#endif
 
-/* Sets up a proper GDT.  The bootstrap loader's GDT didn't
-   include user-mode selectors or a TSS. */
-static void
-gdt_init (void)
-{
-  uint64_t gdtr_operand;
-
-  /* Our TSS is never used in a call gate or task gate, so only a
-     few fields of it are ever referenced, and those are the only
-     ones we initialize. */
-  tss = palloc_get (PAL_ASSERT | PAL_ZERO);
-  tss->esp0 = (uint32_t) ptov(0x20000);
-  tss->ss0 = SEL_KDSEG;
-  tss->bitmap = 0xdfff;
-
-  /* Initialize GDT. */
-  gdt[SEL_NULL / sizeof *gdt] = 0;
-  gdt[SEL_KCSEG / sizeof *gdt] = make_code_desc (0);
-  gdt[SEL_KDSEG / sizeof *gdt] = make_data_desc (0);
-  gdt[SEL_UCSEG / sizeof *gdt] = make_code_desc (3);
-  gdt[SEL_UDSEG / sizeof *gdt] = make_data_desc (3);
-  gdt[SEL_TSS / sizeof *gdt] = make_tss_desc (tss);
-
-  /* Load GDTR, TR. */
-  gdtr_operand = make_dtr_operand (sizeof gdt - 1, gdt);
-  asm volatile ("lgdt %0" :: "m" (gdtr_operand));
-  asm volatile ("ltr %w0" :: "r" (SEL_TSS));
+  /* Terminate this thread. */
+  thread_exit ();
 }
-
+
+/* Clear BSS and obtain RAM size from loader. */
 static void
 ram_init (void) 
 {
@@ -178,10 +119,11 @@ ram_init (void)
   extern char _start_bss, _end_bss;
   memset (&_start_bss, 0, &_end_bss - &_start_bss);
 
-  /* Get RAM size from loader. */
+  /* Get RAM size from loader.  See loader.S. */
   ram_pages = *(uint32_t *) ptov (LOADER_RAM_PAGES);
 }
-
+
+/* Parses the command line. */
 static void
 argv_init (void) 
 {
@@ -243,8 +185,9 @@ argv_init (void)
           " -p FILENAME         Print the contents of FILENAME\n"
           " -r FILENAME         Delete FILENAME\n"
           " -ls                 List the files in the filesystem\n"
-          " -D                  Dump complete filesystem contents\n");
+          " -D                  Dump complete filesystem contents\n"
 #endif
+          );
       }
     else 
       PANIC ("unknown option `%s'", argv[i]);