Start work on kernel start-up code.

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

diff --git a/src/threads/init.c b/src/threads/init.c
index c17316aa59efec1951ad48eed5c8e4522a3e0381..b98e580feab1e59eae30775fd62f696cd2bd3f10 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
 
@@ -80,9 +78,9 @@ main (void)
   argv_init ();
 
   /* Initialize memory system. */
+  paging_init ();
   palloc_init ();
   malloc_init ();
-  paging_init ();
 
   /* Segmentation. */
 #ifdef USERPROG
@@ -108,8 +106,9 @@ main (void)
   timer_calibrate ();
 
 #ifdef FILESYS
-  /* Initialize filesystem. */
+  /* Initialize file system. */
   disk_init ();
+  partition_init ();
   filesys_init (format_filesys);
   fsutil_run ();
 #endif
@@ -152,9 +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
@@ -163,8 +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)
@@ -172,8 +168,8 @@ paging_init (void)
   uint32_t *pd, *pt;
   size_t page;
 
-  pd = base_page_dir = palloc_get_page (PAL_ASSERT | PAL_ZERO);
-  pt = NULL;
+  pd = base_page_dir = ptov (LOADER_PD_BASE);
+  pt = ptov (LOADER_PT_BASE);
   for (page = 0; page < ram_pages; page++) 
     {
       uintptr_t paddr = page * PGSIZE;
@@ -183,16 +179,22 @@ paging_init (void)
 
       if (pd[pde_idx] == 0)
         {
-          pt = palloc_get_page (PAL_ASSERT | PAL_ZERO);
+          pt += PGSIZE / sizeof *pt;
+          memset (pt, 0, PGSIZE);
           pd[pde_idx] = pde_create (pt);
         }
 
       pt[pte_idx] = pte_create_kernel (vaddr, true);
     }
 
+  /* start.S mapped the beginning of physical memory to virtual
+     address 0.  We don't want that mapping anymore, so erase
+     it. */
+  pd[0] = 0;
+
   /* 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
+     aka PDBR (page directory base register).  This flushes the
+     TLB to make sure .  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)));
 }
@@ -267,15 +269,15 @@ 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"