Add memory clobbers to several asm statements,

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

diff --git a/src/threads/init.c b/src/threads/init.c
index 458f67cb2bbd7a7424950d8a219c9f08747c30f8..5961deba3e6f8d82cd0e75abab89321d87cda597 100644 (file)
--- a/src/threads/init.c
+++ b/src/threads/init.c
@@ -41,11 +41,6 @@ size_t ram_pages;
 /* Page directory with kernel mappings only. */
 uint32_t *base_page_dir;
 
-/* -mlfqs:
-   If false (default), use round-robin scheduler.
-   If true, use multi-level feedback queue scheduler. */
-bool enable_mlfqs;
-
 #ifdef FILESYS
 /* -f: Format the file system? */
 static bool format_filesys;
@@ -168,15 +163,17 @@ paging_init (void)
 {
   uint32_t *pd, *pt;
   size_t page;
+  extern char _start, _end_kernel_text;
 
   pd = base_page_dir = palloc_get_page (PAL_ASSERT | PAL_ZERO);
   pt = NULL;
   for (page = 0; page < ram_pages; page++) 
     {
       uintptr_t paddr = page * PGSIZE;
-      void *vaddr = ptov (paddr);
+      char *vaddr = ptov (paddr);
       size_t pde_idx = pd_no (vaddr);
       size_t pte_idx = pt_no (vaddr);
+      bool in_kernel_text = &_start <= vaddr && vaddr < &_end_kernel_text;
 
       if (pd[pde_idx] == 0)
         {
@@ -184,7 +181,7 @@ paging_init (void)
           pd[pde_idx] = pde_create (pt);
         }
 
-      pt[pte_idx] = pte_create_kernel (vaddr, true);
+      pt[pte_idx] = pte_create_kernel (vaddr, !in_kernel_text);
     }
 
   /* Store the physical address of the page directory into CR3
@@ -252,7 +249,7 @@ parse_options (char **argv)
       else if (!strcmp (name, "-rs"))
         random_init (atoi (value));
       else if (!strcmp (name, "-mlfqs"))
-        enable_mlfqs = true;
+        thread_mlfqs = true;
 #ifdef USERPROG
       else if (!strcmp (name, "-ul"))
         user_page_limit = atoi (value);
@@ -385,7 +382,7 @@ power_off (void)
 
   for (p = s; *p != '\0'; p++)
     outb (0x8900, *p);
-  asm ("cli; hlt");
+  asm volatile ("cli; hlt" : : : "memory");
   printf ("still running...\n");
   for (;;);
 }