WebSVN – HelenOS – Diff – /branches/arm/kernel/arch/arm32/include/mm/page.h

 #   define PA2KA(x) ((x) + 0x80000000)
 #endif
 #ifdef KERNEL
-// "small" pages (4KB) used
 #define PTL0_ENTRIES_ARCH    (2<<12)    // 4096
 #define PTL1_ENTRIES_ARCH     0
 #define PTL2_ENTRIES_ARCH     0
+/* coarse page tables used (256*4 = 1KB per page) */
 #define PTL3_ENTRIES_ARCH    (2<<8)     // 256
 #define PTL0_INDEX_ARCH(vaddr)    (((vaddr) >> 20) & 0xfff)
 #define PTL1_INDEX_ARCH(vaddr)    0
 #define PTL2_INDEX_ARCH(vaddr)    0
+/* TODO: ?? 0xfff or 0x0ff */
-#define PTL3_INDEX_ARCH(vaddr)    (((vaddr) >> 12) & 0x0ff)
+#define PTL3_INDEX_ARCH(vaddr)    (((vaddr) >> 12) & 0xfff)
 #define GET_PTL1_ADDRESS_ARCH(ptl0, i)      ((pte_t *)( (((pte_level0_t*)(ptl0))[(i)]).coarse_table_addr << 10 ))
 #define GET_PTL2_ADDRESS_ARCH(ptl1, i)      (ptl1)
 #define GET_PTL3_ADDRESS_ARCH(ptl2, i)      (ptl2)
 #define GET_FRAME_ADDRESS_ARCH(ptl3, i)     ((uintptr_t)( (((pte_level1_t*)(ptl3))[(i)]).frame_base_addr << 12 ))
 #define SET_PTL2_FLAGS_ARCH(ptl1, i, x)
 #define SET_PTL3_FLAGS_ARCH(ptl2, i, x)
 #define SET_FRAME_FLAGS_ARCH(ptl3, i, x)    set_pt_level1_flags((pte_level1_t *)(ptl3), (index_t)(i), (x))
 #define PTE_VALID_ARCH(pte)                 (*((uint32_t *) (pte)) != 0)
+// TODO: ?? != 0
-#define PTE_PRESENT_ARCH(pte)               ( ((pte_level0_t *)(pte))->descriptor_type )
+#define PTE_PRESENT_ARCH(pte)               ( ((pte_level0_t *)(pte))->descriptor_type != 0 )
-// pte should point into ptl3
+/* pte should point into ptl3 */
 #define PTE_GET_FRAME_ARCH(pte)             ( ((pte_level1_t *)(pte))->frame_base_addr << FRAME_WIDTH)
-// pte should point into ptl3
+/* pte should point into ptl3 */
 #define PTE_WRITABLE_ARCH(pte)              ( ((pte_level1_t *)(pte))->access_permission_0 == pte_ap_user_rw_kernel_rw )
 #define PTE_EXECUTABLE_ARCH(pte)            1
 #ifndef __ASM__
+/**
-/** Sets the address of level 0 page table.
+ * Sets the address of level 0 page table.
+ *
- * \param pt pointer to the page table to set
+ * \param pt    pointer to the page table to set
  */
 static inline void set_ptl0_addr( pte_level0_t* pt)
+{
     asm volatile ( "mcr p15, 0, %0, c2, c0, 0 \n"
+        :
         : "r"(pt)
     );
+}
+/**
+ * Returns level 0 page table entry flags.
+ *
+ * \param pt     level 0 page table
-//TODO Comment: Page table structure as in other architectures
+ * \param i      index of the entry to return
+ */
 static inline int get_pt_level0_flags(pte_level0_t *pt, index_t i)
+{
     pte_level0_t *p = &pt[i];
     return (
         ( p->descriptor_type != pte_descriptor_not_preset ) << PAGE_PRESENT_SHIFT |
+        ( 1 << PAGE_USER_SHIFT )  |
-        ( 1 << PAGE_READ_SHIFT ) |
+        ( 1 << PAGE_READ_SHIFT )  |
+        ( 1 << PAGE_WRITE_SHIFT ) |
-        ( 1 << PAGE_EXEC_SHIFT ) |
+        ( 1 << PAGE_EXEC_SHIFT )  |
-        ( 1 << PAGE_CACHEABLE  )
+        ( 1 << PAGE_CACHEABLE_SHIFT  )
     );
+}
+/**
+ * Returns level 1 page table entry flags.
+ *
+ * \param pt     level 1 page table
+ * \param i      index of the entry to return
+ */
 static inline int get_pt_level1_flags(pte_level1_t *pt, index_t i)
+{
-  pte_level1_t *p = &pt[i];
+    pte_level1_t *p = &pt[i];
     return (
         ( p->descriptor_type != pte_descriptor_not_preset )    << PAGE_PRESENT_SHIFT |
         ( (p->access_permission_0 == pte_ap_user_ro_kernel_rw) << PAGE_READ_SHIFT )  |
         ( (p->access_permission_0 == pte_ap_user_rw_kernel_rw) << PAGE_READ_SHIFT )  |
         ( (p->access_permission_0 == pte_ap_user_rw_kernel_rw) << PAGE_WRITE_SHIFT ) |
         ( (p->access_permission_0 != pte_ap_user_no_kernel_rw) << PAGE_USER_SHIFT )  |
         ( 1 << PAGE_EXEC_SHIFT ) |
-        ( p->bufferable << PAGE_CACHEABLE  )
+        ( p->bufferable << PAGE_CACHEABLE )
     );
+}
+/**
+ * Sets flags of level 0 page table entry.
+ *
+ * \param pt     level 0 page table
+ * \param i      index of the entry to be changed
+ * \param flags  new flags
+ *
+ * TODO: why should_be_zero set to 1?
+ */
 static inline void set_pt_level0_flags(pte_level0_t *pt, index_t i, int flags)
+{
     pte_level0_t *p = &pt[i];
-    if ( flags & PAGE_NOT_PRESENT ) {
+    if (flags & PAGE_NOT_PRESENT) {
         p->descriptor_type = pte_descriptor_not_preset;
         p->should_be_zero  = 1;
     } else {
         p->descriptor_type = pte_descriptor_coarse_table;
         p->should_be_zero  = 0;
+    }
+}
+/**
+ * Sets flags of level 1 page table entry.
+ *
-/* TODO: rewrite comment: We use same acess rights for whole page, so if page is set as not preset then
+ * We use same access rights for the whole page. When page is not preset then
- * in acess_rigts_3 set value 1
+ * store 1 in acess_rigts_3.
+ * TODO: why access_right_3?
+ *
+ * \param pt     level 1 page table
+ * \param i      index of the entry to be changed
+ * \param flags  new flags
  */
 static inline void set_pt_level1_flags(pte_level1_t *pt, index_t i, int flags)
+{
     pte_level1_t *p = &pt[i];
-    if ( flags & PAGE_NOT_PRESENT ) {
+    if (flags & PAGE_NOT_PRESENT) {
         p->descriptor_type      = pte_descriptor_not_preset;
         p->access_permission_3  = 1;
     } else {
-        p->descriptor_type      = pte_descriptor_coarse_table;
+        p->descriptor_type      = pte_descriptor_small_page;
         p->access_permission_3  = p->access_permission_0;
+    }
     p->cacheable = p->bufferable = (flags & PAGE_CACHEABLE) != 0;
-    // default kernel rw, user none
+    /* default access permission */
     p->access_permission_0 = p->access_permission_1 =
         p->access_permission_2 = p->access_permission_3 = pte_ap_user_no_kernel_rw;
-    if ( flags & PAGE_USER )  {
+    if (flags & PAGE_USER)  {
-        if ( flags & PAGE_READ ) {
+        if (flags & PAGE_READ) {
             p->access_permission_0 = p->access_permission_1 =
                 p->access_permission_2 = p->access_permission_3 =
                 pte_ap_user_ro_kernel_rw;
+        }
-        if ( flags & PAGE_WRITE ) {
+        if (flags & PAGE_WRITE) {
             p->access_permission_0 = p->access_permission_1 =
                 p->access_permission_2 = p->access_permission_3 =
                 pte_ap_user_rw_kernel_rw;
+        }
+    }

Subversion Repositories HelenOS

(root)/branches/arm/kernel/arch/arm32/include/mm/page.h – Rev 2238 → 2241