Changeset c03ee1c in mainline for kernel/arch/arm32/include/mm/page.h

Timestamp:

2007-06-13T17:49:57Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

de7663f

Parents:

6b781c0

Message:

Improve comments for arch-specific implementations of hierarchical
4-level page tables. Improve formatting.

File:

• kernel/arch/arm32/include/mm/page.h (modified) (12 diffs)

kernel/arch/arm32/include/mm/page.h

@@ -56 +56 @@
 #ifdef KERNEL
 
+/* Number of entries in each level. */
 #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 */
 
+/* Page table sizes for each level. */
 #define PTL0_SIZE_ARCH          FOUR_FRAMES
 #define PTL1_SIZE_ARCH          0
@@ -68 +69 @@
 #define PTL3_SIZE_ARCH          ONE_FRAME
 
+/* Macros calculating indices into page tables for each level. */
 #define PTL0_INDEX_ARCH(vaddr)  (((vaddr) >> 20) & 0xfff)
 #define PTL1_INDEX_ARCH(vaddr)  0
@@ -73 +75 @@
 #define PTL3_INDEX_ARCH(vaddr)  (((vaddr) >> 12) & 0x0ff)
 
+/* Get PTE address accessors for each level. */
 #define GET_PTL1_ADDRESS_ARCH(ptl0, i) \
         ((pte_t *) ((((pte_level0_t *)(ptl0))[(i)]).coarse_table_addr << 10))
@@ -82 +85 @@
         ((uintptr_t) ((((pte_level1_t *)(ptl3))[(i)]).frame_base_addr << 12))
 
+/* Set PTE address accessors for each level. */
 #define SET_PTL0_ADDRESS_ARCH(ptl0) \
         (set_ptl0_addr((pte_level0_t *) (ptl0)))
@@ -91 +95 @@
         (((pte_level1_t *) (ptl3))[(i)].frame_base_addr = (a) >> 12)
 
+/* Get PTE flags accessors for each level. */
 #define GET_PTL1_FLAGS_ARCH(ptl0, i) \
         get_pt_level0_flags((pte_level0_t *) (ptl0), (index_t) (i))
@@ -100 +105 @@
         get_pt_level1_flags((pte_level1_t *) (ptl3), (index_t) (i))
 
+/* Set PTE flags accessors for each level. */
 #define SET_PTL1_FLAGS_ARCH(ptl0, i, x) \
         set_pt_level0_flags((pte_level0_t *) (ptl0), (index_t) (i), (x))
@@ -107 +113 @@
         set_pt_level1_flags((pte_level1_t *) (ptl3), (index_t) (i), (x))
 
+/* Macros for querying the last-level PTE entries. */
 #define PTE_VALID_ARCH(pte) \
         (*((uint32_t *) (pte)) != 0)
 #define PTE_PRESENT_ARCH(pte) \
         (((pte_level0_t *) (pte))->descriptor_type != 0)
-
-/* 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 */
 #define PTE_WRITABLE_ARCH(pte) \
         (((pte_level1_t *) (pte))->access_permission_0 == \
             PTE_AP_USER_RW_KERNEL_RW)
-
 #define PTE_EXECUTABLE_ARCH(pte) \
         1
@@ -129 +131 @@
 typedef struct {
         /* 0b01 for coarse tables, see below for details */
-        unsigned descriptor_type     : 2;
-        unsigned impl_specific       : 3;
-        unsigned domain              : 4;
-        unsigned should_be_zero      : 1;
+        unsigned descriptor_type : 2;
+        unsigned impl_specific : 3;
+        unsigned domain : 4;
+        unsigned should_be_zero : 1;
 
         /* Pointer to the coarse 2nd level page table (holding entries for small
@@ -139 +141 @@
          * per table in comparison with 1KB per the coarse table)
          */
-        unsigned coarse_table_addr   : 22;
+        unsigned coarse_table_addr : 22;
 } ATTRIBUTE_PACKED pte_level0_t;
 
@@ -146 +148 @@
 
         /* 0b10 for small pages */
-        unsigned descriptor_type     : 2;
-        unsigned bufferable          : 1;
-        unsigned cacheable           : 1;
+        unsigned descriptor_type : 2;
+        unsigned bufferable : 1;
+        unsigned cacheable : 1;
 
         /* access permissions for each of 4 subparts of a page
@@ -156 +158 @@
         unsigned access_permission_2 : 2;
         unsigned access_permission_3 : 2;
-        unsigned frame_base_addr     : 20;
+        unsigned frame_base_addr : 20;
 } ATTRIBUTE_PACKED pte_level1_t;
 
@@ -191 +193 @@
  * @param pt    Pointer to the page table to set.
  */   
-static inline void set_ptl0_addr( pte_level0_t *pt)
+static inline void set_ptl0_addr(pte_level0_t *pt)
 {
         asm volatile (