X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=inline;f=src%2Fthreads%2Fpaging.c;h=587813cb3c3707071316d9926979873a98d8f91e;hb=994aa9cbadb9bb822df3adfffad8de40997fc562;hp=190d4fc27394feec77570944dcfa588779690dc8;hpb=8ca3547f6c4d6d01a76d3ce642a0c1bf884c4c2a;p=pintos-anon

diff --git a/src/threads/paging.c b/src/threads/paging.c
index 190d4fc..587813c 100644
--- a/src/threads/paging.c
+++ b/src/threads/paging.c
@@ -8,33 +8,26 @@
 
 static uint32_t *base_page_dir;
 
-static uint32_t
-make_pde (uint32_t *pagetab) 
-{
-  ASSERT (PGOFS ((uintptr_t) pagetab) == 0);
-  
-  return vtop (pagetab) | PG_U | PG_P | PG_W;
+static uint32_t make_pde (uint32_t *pt) {
+  ASSERT (pg_ofs (pt) == 0);
+  return vtop (pt) | PG_U | PG_P | PG_W;
 }
 
-static uint32_t
-make_pte (uint32_t *page, bool writable)
-{
-  uint32_t entry;
+static uint32_t make_kernel_pte (uint32_t *page, bool writable) {
+  ASSERT (pg_ofs (page) == 0);
+  return vtop (page) | PG_P | (writable ? PG_W : 0);
+}
 
-  ASSERT (PGOFS ((uintptr_t) page) == 0);
-  
-  entry = vtop (page) | PG_U | PG_P;
-  if (writable)
-    entry |= PG_W;
-  return entry;
+static uint32_t make_user_pte (uint32_t *page, bool writable) {
+  return make_kernel_pte (page, writable) | PG_U;
 }
 
 static uint32_t *
-pde_get_pagetab (uint32_t pde) 
+pde_get_pt (uint32_t pde) 
 {
   ASSERT (pde & PG_P);
 
-  return ptov (PGROUNDDOWN (pde));
+  return ptov (pde & ~PGMASK);
 }
 
 static void *
@@ -42,7 +35,7 @@ pte_get_page (uint32_t pte)
 {
   ASSERT (pte & PG_P);
   
-  return ptov (PGROUNDDOWN (pte));
+  return ptov (pte & ~PGMASK);
 }
 
 /* Populates the base page directory and page table with the
@@ -50,9 +43,9 @@ pte_get_page (uint32_t pte)
    new page directory.
 
    At the time this function is called, the active page table
-   only maps the first 4 MB of RAM, so it should not try to use
-   extravagant amounts of memory.  Fortunately, there is no need
-   to do so. */
+   (set up by loader.S) only maps the first 4 MB of RAM, so we
+   should not try to use extravagant amounts of memory.
+   Fortunately, there is no need to do so. */
 void
 paging_init (void)
 {
@@ -63,10 +56,10 @@ paging_init (void)
   pt = NULL;
   for (page = 0; page < ram_pages; page++) 
     {
-      uintptr_t paddr = page * NBPG;
+      uintptr_t paddr = page * PGSIZE;
       void *vaddr = ptov (paddr);
-      size_t pde_idx = PDENO ((uintptr_t) vaddr);
-      size_t pte_idx = PTENO ((uintptr_t) vaddr);
+      size_t pde_idx = pd_no (vaddr);
+      size_t pte_idx = pt_no (vaddr);
 
       if (pd[pde_idx] == 0)
         {
@@ -74,18 +67,17 @@ paging_init (void)
           pd[pde_idx] = make_pde (pt);
         }
 
-      pt[pte_idx] = make_pte (vaddr, true);
+      pt[pte_idx] = make_kernel_pte (vaddr, true);
     }
 
-  /* Set the page table. */
-  asm volatile ("movl %0,%%cr3" :: "r" (vtop (pd)));
+  pagedir_activate (pd);
 }
 
 uint32_t *
 pagedir_create (void) 
 {
   uint32_t *pd = palloc_get (0);
-  memcpy (pd, base_page_dir, NBPG);
+  memcpy (pd, base_page_dir, PGSIZE);
   return pd;
 }
 
@@ -101,49 +93,49 @@ pagedir_destroy (uint32_t *pd)
 }
 
 static uint32_t *
-lookup_page (uint32_t *pagedir, void *upage, bool create)
+lookup_page (uint32_t *pd, void *upage, bool create)
 {
-  uint32_t *pagetab;
+  uint32_t *pt;
   uint32_t *pde;
 
-  ASSERT (pagedir != NULL);
-  ASSERT (PGOFS ((uintptr_t) upage) == 0);
-  ASSERT ((uintptr_t) upage < PHYS_BASE);
+  ASSERT (pd != NULL);
+  ASSERT (pg_ofs (upage) == 0);
+  ASSERT (upage < PHYS_BASE);
 
   /* Check for a page table for UPAGE.
      If one is missing, create one if requested. */
-  pde = pagedir + PDENO ((uint32_t) upage);
+  pde = pd + pd_no (upage);
   if (*pde == 0) 
     {
       if (create)
         {
-          pagetab = palloc_get (PAL_ZERO);
-          if (pagetab == NULL) 
+          pt = palloc_get (PAL_ZERO);
+          if (pt == NULL) 
             return NULL; 
       
-          *pde = make_pde (pagetab);
+          *pde = make_pde (pt);
         }
       else
         return NULL;
     }
 
   /* Return the page table entry. */
-  pagetab = pde_get_pagetab (*pde);
-  return &pagetab[PTENO ((uintptr_t) upage)];
+  pt = pde_get_pt (*pde);
+  return &pt[pt_no (upage)];
 }
 
 bool
-pagedir_set_page (uint32_t *pagedir, void *upage, void *kpage,
+pagedir_set_page (uint32_t *pd, void *upage, void *kpage,
                   bool writable) 
 {
   uint32_t *pte;
 
-  ASSERT (PGOFS ((uintptr_t) kpage) == 0);
+  ASSERT (pg_ofs (kpage) == 0);
 
-  pte = lookup_page (pagedir, upage, true);
+  pte = lookup_page (pd, upage, true);
   if (pte != NULL) 
     {
-      *pte = make_pte (kpage, writable);
+      *pte = make_user_pte (kpage, writable);
       return true;
     }
   else
@@ -151,16 +143,16 @@ pagedir_set_page (uint32_t *pagedir, void *upage, void *kpage,
 }
 
 void *
-pagedir_get_page (uint32_t *pagedir, void *upage) 
+pagedir_get_page (uint32_t *pd, void *upage) 
 {
-  uint32_t *pte = lookup_page (pagedir, upage, false);
+  uint32_t *pte = lookup_page (pd, upage, false);
   return pte != NULL && *pte != 0 ? pte_get_page (*pte) : NULL;
 }
 
 void
-pagedir_clear_page (uint32_t *pagedir, void *upage)
+pagedir_clear_page (uint32_t *pd, void *upage)
 {
-  uint32_t *pte = lookup_page (pagedir, upage, false);
+  uint32_t *pte = lookup_page (pd, upage, false);
   if (pte != NULL)
     *pte = 0;
 }
@@ -168,7 +160,7 @@ pagedir_clear_page (uint32_t *pagedir, void *upage)
 static uint32_t *
 scan_pt (uint32_t *pt, unsigned pde_idx, unsigned pte_idx, void **upage) 
 {
-  for (; pte_idx < NBPG / sizeof *pt; pte_idx++) 
+  for (; pte_idx < PGSIZE / sizeof *pt; pte_idx++) 
     {
       uint32_t pte = pt[pte_idx];
 
@@ -177,8 +169,7 @@ scan_pt (uint32_t *pt, unsigned pde_idx, unsigned pte_idx, void **upage)
           void *kpage = pte_get_page (pte);
           if (kpage != NULL) 
             {
-              *upage = (void *) ((pde_idx << PDSHIFT)
-                                 | (pte_idx << PGSHIFT));
+              *upage = (void *) ((pde_idx << PDSHIFT) | (pte_idx << PTSHIFT));
               return kpage;
             }
         }
@@ -190,13 +181,13 @@ scan_pt (uint32_t *pt, unsigned pde_idx, unsigned pte_idx, void **upage)
 static void *
 scan_pd (uint32_t *pd, unsigned pde_idx, void **upage) 
 {
-  for (; pde_idx < PDENO (PHYS_BASE); pde_idx++) 
+  for (; pde_idx < pd_no (PHYS_BASE); pde_idx++) 
     {
       uint32_t pde = pd[pde_idx];
 
       if (pde != 0) 
         {
-          void *kpage = scan_pt (pde_get_pagetab (pde), pde_idx, 0, upage);
+          void *kpage = scan_pt (pde_get_pt (pde), pde_idx, 0, upage);
           if (kpage != NULL)
             return kpage;
         }
@@ -206,9 +197,9 @@ scan_pd (uint32_t *pd, unsigned pde_idx, void **upage)
 }
 
 void *
-pagedir_first (uint32_t *pagedir, void **upage) 
+pagedir_first (uint32_t *pd, void **upage) 
 {
-  return scan_pd (pagedir, 0, upage);
+  return scan_pd (pd, 0, upage);
 }
 
 void *
@@ -217,13 +208,17 @@ pagedir_next (uint32_t *pd, void **upage)
   unsigned pde_idx, pte_idx;
   void *kpage;
 
-  pde_idx = PDENO (*upage);
-  pte_idx = PTENO (*upage);
-  kpage = scan_pt (pde_get_pagetab (pd[pde_idx]),
+  pde_idx = pd_no (*upage);
+  pte_idx = pt_no (*upage);
+  kpage = scan_pt (pde_get_pt (pd[pde_idx]),
                    pde_idx, pte_idx + 1, upage);
   if (kpage == NULL)
     kpage = scan_pd (pd, pde_idx + 1, upage);
   return kpage;
 }
 
-void pagedir_activate (uint32_t *pagedir);
+void
+pagedir_activate (uint32_t *pd) 
+{
+  asm volatile ("movl %0,%%cr3" :: "r" (vtop (pd)));
+}