Userspace almost (?) working.

[pintos-anon] / src / userprog / addrspace.c

diff --git a/src/userprog/addrspace.c b/src/userprog/addrspace.c
index 4e317c56bf184ca03a7265639da7611a31cbec54..eb0de496851a5a340270e8d1cdd38074d677d88e 100644 (file)
--- a/src/userprog/addrspace.c
+++ b/src/userprog/addrspace.c
@@ -78,11 +78,26 @@ struct Elf32_Phdr
                 goto error;                                     \
         } while (0)
 
+static bool
+install_page (struct addrspace *as, void *upage, void *kpage)
+{
+  /* Verify that there's not already a page at that virtual
+     address, then map our page there. */
+  if (pagedir_get_page (as->pagedir, upage) == NULL
+      && pagedir_set_page (as->pagedir, upage, kpage, true))
+    return true;
+  else
+    {
+      palloc_free (kpage);
+      return false;
+    }
+}
+
 static bool
 load_segment (struct addrspace *as, struct file *file,
               const struct Elf32_Phdr *phdr) 
 {
-  uintptr_t start, end;
+  void *start, *end;
   uint8_t *upage;
   off_t filesz_left;
 
@@ -91,11 +106,11 @@ load_segment (struct addrspace *as, struct file *file,
   ASSERT (phdr != NULL);
   ASSERT (phdr->p_type == PT_LOAD);
 
-  /* p_offset and p_vaddr must be congruent modulo NBPG. */
-  if (phdr->p_offset % NBPG != phdr->p_vaddr % NBPG) 
+  /* p_offset and p_vaddr must be congruent modulo PGSIZE. */
+  if (phdr->p_offset % PGSIZE != phdr->p_vaddr % PGSIZE) 
     {
       printk ("%#08"PE32Ox" and %#08"PE32Ax" not congruent modulo %#x\n",
-              phdr->p_offset, phdr->p_vaddr, (unsigned) NBPG);
+              phdr->p_offset, phdr->p_vaddr, (unsigned) PGSIZE);
       return false; 
     }
 
@@ -108,8 +123,8 @@ load_segment (struct addrspace *as, struct file *file,
     }
 
   /* Validate virtual memory region to be mapped. */
-  start = PGROUNDDOWN (phdr->p_vaddr);
-  end = PGROUNDUP (phdr->p_vaddr + phdr->p_memsz);
+  start = pg_round_down ((void *) phdr->p_vaddr);
+  end = pg_round_up ((void *) (phdr->p_vaddr + phdr->p_memsz));
   if (start >= PHYS_BASE || end >= PHYS_BASE || end < start) 
     {
       printk ("bad virtual region %08lx...%08lx\n",
@@ -117,12 +132,12 @@ load_segment (struct addrspace *as, struct file *file,
       return false; 
     }
 
-  filesz_left = phdr->p_filesz + (phdr->p_vaddr - start);
-  file_seek (file, ROUND_DOWN (phdr->p_offset, NBPG));
-  for (upage = (uint8_t *) start; upage < (uint8_t *) end; upage += NBPG) 
+  filesz_left = phdr->p_filesz + (phdr->p_vaddr & PGMASK);
+  file_seek (file, ROUND_DOWN (phdr->p_offset, PGSIZE));
+  for (upage = start; upage < (uint8_t *) end; upage += PGSIZE) 
     {
-      size_t read_bytes = filesz_left >= NBPG ? NBPG : filesz_left;
-      size_t zero_bytes = NBPG - read_bytes;
+      size_t read_bytes = filesz_left >= PGSIZE ? PGSIZE : filesz_left;
+      size_t zero_bytes = PGSIZE - read_bytes;
       uint8_t *kpage = palloc_get (0);
       if (kpage == NULL)
         return false;
@@ -132,19 +147,29 @@ load_segment (struct addrspace *as, struct file *file,
       memset (kpage + read_bytes, 0, zero_bytes);
       filesz_left -= read_bytes;
 
-      if (pagedir_get_page (as->pagedir, upage))
-        {
-          palloc_free (kpage);
-          return false;
-        }
-      pagedir_set_page (as->pagedir, upage, kpage, true);
+      if (!install_page (as, upage, kpage))
+        return false;
     }
 
   return true;
 }
 
+static bool
+setup_stack (struct addrspace *as) 
+{
+  uint8_t *kpage = palloc_get (PAL_ZERO);
+  if (kpage == NULL)
+    {
+      printk ("failed to allocate process stack\n");
+      return false;
+    }
+
+  return install_page (as, ((uint8_t *) PHYS_BASE) - PGSIZE, kpage);
+}
+
 bool
-addrspace_load (struct addrspace *as, const char *filename) 
+addrspace_load (struct addrspace *as, const char *filename,
+                void (**start) (void)) 
 {
   struct Elf32_Ehdr ehdr;
   struct file *file = NULL;
@@ -177,7 +202,6 @@ addrspace_load (struct addrspace *as, const char *filename)
 
   /* Read program headers. */
   file_ofs = ehdr.e_phoff;
-  printk ("e_phnum=%d\n", ehdr.e_phnum);
   for (i = 0; i < ehdr.e_phnum; i++) 
     {
       struct Elf32_Phdr phdr;
@@ -196,7 +220,7 @@ addrspace_load (struct addrspace *as, const char *filename)
         case PT_NULL:
         case PT_NOTE:
         case PT_PHDR:
-        case PT_STACK: /* Stack segment. */
+        case PT_STACK:
           /* Ignore this segment. */
           break;
         case PT_DYNAMIC:
@@ -214,6 +238,14 @@ addrspace_load (struct addrspace *as, const char *filename)
           break;
         }
     }
+
+  /* Set up stack. */
+  if (!setup_stack (as))
+    goto error;
+
+  /* Start address. */
+  *start = (void (*) (void)) ehdr.e_entry;
+
   success = true;
 
  error:
@@ -230,3 +262,12 @@ addrspace_destroy (struct addrspace *as)
   if (as != NULL && as->pagedir != NULL) 
     pagedir_destroy (as->pagedir); 
 }
+
+void
+addrspace_activate (struct addrspace *as) 
+{
+  ASSERT (as != NULL);
+  
+  if (as->pagedir != NULL)
+    pagedir_activate (as->pagedir);
+}