Rewrite palloc code so that it only touches the first 4 MB of RAM.

[pintos-anon] / src / threads / init.c

diff --git a/src/threads/init.c b/src/threads/init.c
index ef67071aec53daceb476b02faf3af4fe48fd7824..3b313287183c06cd1f7286a246bd7518a766dda5 100644 (file)
--- a/src/threads/init.c
+++ b/src/threads/init.c
@@ -29,18 +29,16 @@
 #endif
 #ifdef FILESYS
 #include "devices/disk.h"
+#include "devices/partition.h"
 #include "filesys/filesys.h"
 #include "filesys/fsutil.h"
 #endif
 
-/* Amount of physical memory, in 4 kB pages. */
-size_t ram_pages;
-
 /* Page directory with kernel mappings only. */
 uint32_t *base_page_dir;
 
 #ifdef FILESYS
-/* -f: Format the filesystem? */
+/* -f: Format the file system? */
 static bool format_filesys;
 #endif
 
@@ -49,8 +47,8 @@ static bool format_filesys;
 static char *initial_program;
 #endif
 
-/* -q: Power off after running requested actions? */
-static bool do_power_off;
+/* -q: Power off after kernel tasks complete? */
+bool power_off_when_done;
 
 static void ram_init (void);
 static void paging_init (void);
@@ -81,8 +79,8 @@ main (void)
 
   /* Initialize memory system. */
   palloc_init ();
-  malloc_init ();
   paging_init ();
+  malloc_init ();
 
   /* Segmentation. */
 #ifdef USERPROG
@@ -105,10 +103,12 @@ main (void)
   /* Start thread scheduler and enable interrupts. */
   thread_start ();
   serial_init_queue ();
+  timer_calibrate ();
 
 #ifdef FILESYS
-  /* Initialize filesystem. */
+  /* Initialize file system. */
   disk_init ();
+  partition_init ();
   filesys_init (format_filesys);
   fsutil_run ();
 #endif
@@ -133,7 +133,7 @@ main (void)
 #endif
 
   /* Finish up. */
-  if (do_power_off) 
+  if (power_off_when_done) 
     power_off ();
   else 
     thread_exit ();
@@ -151,9 +151,6 @@ ram_init (void)
      linker as _start_bss and _end_bss.  See kernel.lds. */
   extern char _start_bss, _end_bss;
   memset (&_start_bss, 0, &_end_bss - &_start_bss);
-
-  /* Get RAM size from loader.  See loader.S. */
-  ram_pages = *(uint32_t *) ptov (LOADER_RAM_PAGES);
 }
 
 /* Populates the base page directory and page table with the
@@ -162,8 +159,8 @@ ram_init (void)
    directory it creates.
 
    At the time this function is called, the active page table
-   (set up by loader.S) only maps the first 4 MB of RAM, so we
-   should not try to use extravagant amounts of memory.
+   (set up by start.S) only maps the first 4 MB of RAM, so we
+   should not try to access memory beyond that limit.
    Fortunately, there is no need to do so. */
 static void
 paging_init (void)
@@ -189,7 +186,11 @@ paging_init (void)
       pt[pte_idx] = pte_create_kernel (vaddr, true);
     }
 
-  asm volatile ("movl %0,%%cr3" :: "r" (vtop (base_page_dir)));
+  /* Store the physical address of the page directory into CR3
+     aka PDBR (page directory base register).  This activates our
+     new page tables immediately.  See [IA32-v2a] "MOV--Move
+     to/from Control Registers" and [IA32-v3] 3.7.5. */
+  asm volatile ("mov %%cr3, %0" :: "r" (vtop (base_page_dir)));
 }
 
 /* Parses the command line. */
@@ -225,12 +226,12 @@ argv_init (void)
     else if (!strcmp (argv[i], "-d")) 
       debug_enable (argv[++i]);
     else if (!strcmp (argv[i], "-q"))
-      do_power_off = true;
+      power_off_when_done = true;
 #ifdef USERPROG
     else if (!strcmp (argv[i], "-ex")) 
       initial_program = argv[++i];
     else if (!strcmp (argv[i], "-ul"))
-      user_page_limit = atoi (argv[++i]);
+      max_user_pages = atoi (argv[++i]);
 #endif
 #ifdef FILESYS
     else if (!strcmp (argv[i], "-f"))
@@ -262,15 +263,15 @@ argv_init (void)
           " -ul USER_MAX        Limit user memory to USER_MAX pages.\n"
 #endif
 #ifdef FILESYS
-          " -f                  Format the filesystem disk (hdb or hd0:1).\n"
+          " -f                  Format the file system disk (hdb or hd0:1).\n"
           " -ci FILENAME SIZE   Copy SIZE bytes from the scratch disk (hdc\n"
-          "                     or hd1:0) into the filesystem as FILENAME\n"
+          "                     or hd1:0) into the file system as FILENAME\n"
           " -co FILENAME        Copy FILENAME to the scratch disk, with\n"
           "                     size at start of sector 0 and data afterward\n"
           " -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"
+          " -ls                 List the files in the file system\n"
+          " -D                  Dump complete file system contents\n"
 #endif
           " -q                  Power off after doing requested actions.\n"
           " -u                  Print this help message and power off.\n"