Changes in kernel/genarch/src/mm/page_pt.c [235e6c7:caed0279] in mainline

File:

• kernel/genarch/src/mm/page_pt.c (modified) (12 diffs)

kernel/genarch/src/mm/page_pt.c

@@ -39 +39 @@
 #include <mm/page.h>
 #include <mm/frame.h>
+#include <mm/km.h>
 #include <mm/as.h>
 #include <arch/mm/page.h>
@@ -45 +46 @@
 #include <arch/asm.h>
 #include <memstr.h>
+#include <align.h>
+#include <macros.h>
+#include <bitops.h>
 
 static void pt_mapping_insert(as_t *, uintptr_t, uintptr_t, unsigned int);
 static void pt_mapping_remove(as_t *, uintptr_t);
 static pte_t *pt_mapping_find(as_t *, uintptr_t, bool);
+static void pt_mapping_make_global(uintptr_t, size_t);
 
 page_mapping_operations_t pt_mapping_operations = {
         .mapping_insert = pt_mapping_insert,
         .mapping_remove = pt_mapping_remove,
-        .mapping_find = pt_mapping_find
+        .mapping_find = pt_mapping_find,
+        .mapping_make_global = pt_mapping_make_global
 };
 
@@ -75 +81 @@
         
         if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {
-                pte_t *newpt = (pte_t *) frame_alloc(PTL1_SIZE, FRAME_KA);
+                pte_t *newpt = (pte_t *) frame_alloc(PTL1_SIZE,
+                    FRAME_LOWMEM | FRAME_KA);
                 memsetb(newpt, FRAME_SIZE << PTL1_SIZE, 0);
                 SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt));
-                SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
+                SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page),
+                    PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
+                    PAGE_WRITE);
         }
         
@@ -84 +93 @@
         
         if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) {
-                pte_t *newpt = (pte_t *) frame_alloc(PTL2_SIZE, FRAME_KA);
+                pte_t *newpt = (pte_t *) frame_alloc(PTL2_SIZE,
+                    FRAME_LOWMEM | FRAME_KA);
                 memsetb(newpt, FRAME_SIZE << PTL2_SIZE, 0);
                 SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt));
-                SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
+                SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page),
+                    PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
+                    PAGE_WRITE);
         }
         
@@ -93 +105 @@
         
         if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) {
-                pte_t *newpt = (pte_t *) frame_alloc(PTL3_SIZE, FRAME_KA);
+                pte_t *newpt = (pte_t *) frame_alloc(PTL3_SIZE,
+                    FRAME_LOWMEM | FRAME_KA);
                 memsetb(newpt, FRAME_SIZE << PTL3_SIZE, 0);
                 SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt));
-                SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
+                SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page),
+                    PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
+                    PAGE_WRITE);
         }
         
@@ -123 +138 @@
         /*
          * First, remove the mapping, if it exists.
-         *
          */
         
@@ -140 +154 @@
         pte_t *ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
         
-        /* Destroy the mapping. Setting to PAGE_NOT_PRESENT is not sufficient. */
+        /*
+         * Destroy the mapping.
+         * Setting to PAGE_NOT_PRESENT is not sufficient.
+         */
         memsetb(&ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0);
         
         /*
-         * Second, free all empty tables along the way from PTL3 down to PTL0.
-         *
+         * Second, free all empty tables along the way from PTL3 down to PTL0
+         * except those needed for sharing the kernel non-identity mappings.
          */
         
@@ -162 +179 @@
                 /*
                  * PTL3 is empty.
-                 * Release the frame and remove PTL3 pointer from preceding table.
-                 *
-                 */
-                frame_free(KA2PA((uintptr_t) ptl3));
+                 * Release the frame and remove PTL3 pointer from the parent
+                 * table.
+                 */
 #if (PTL2_ENTRIES != 0)
                 memsetb(&ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0);
@@ -171 +187 @@
                 memsetb(&ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
 #else
+                if (km_is_non_identity(page))
+                        return;
+
                 memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
 #endif
+                frame_free(KA2PA((uintptr_t) ptl3));
         } else {
                 /*
@@ -195 +215 @@
                 /*
                  * PTL2 is empty.
-                 * Release the frame and remove PTL2 pointer from preceding table.
-                 *
-                 */
-                frame_free(KA2PA((uintptr_t) ptl2));
+                 * Release the frame and remove PTL2 pointer from the parent
+                 * table.
+                 */
 #if (PTL1_ENTRIES != 0)
                 memsetb(&ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
 #else
+                if (km_is_non_identity(page))
+                        return;
+
                 memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
 #endif
+                frame_free(KA2PA((uintptr_t) ptl2));
         } else {
                 /*
@@ -227 +250 @@
                 /*
                  * PTL1 is empty.
-                 * Release the frame and remove PTL1 pointer from preceding table.
-                 *
-                 */
+                 * Release the frame and remove PTL1 pointer from the parent
+                 * table.
+                 */
+                if (km_is_non_identity(page))
+                        return;
+
+                memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
                 frame_free(KA2PA((uintptr_t) ptl1));
-                memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
         }
 #endif /* PTL1_ENTRIES != 0 */
@@ -267 +293 @@
 }
 
+/** Return the size of the region mapped by a single PTL0 entry.
+ *
+ * @return Size of the region mapped by a single PTL0 entry.
+ */
+static uintptr_t ptl0_step_get(void)
+{
+        size_t va_bits;
+
+        va_bits = fnzb(PTL0_ENTRIES) + fnzb(PTL1_ENTRIES) + fnzb(PTL2_ENTRIES) +
+            fnzb(PTL3_ENTRIES) + PAGE_WIDTH;
+
+        return 1UL << (va_bits - fnzb(PTL0_ENTRIES));
+}
+
+/** Make the mappings in the given range global accross all address spaces.
+ *
+ * All PTL0 entries in the given range will be mapped to a next level page
+ * table. The next level page table will be allocated and cleared.
+ *
+ * pt_mapping_remove() will never deallocate these page tables even when there
+ * are no PTEs in them.
+ *
+ * @param as   Address space.
+ * @param base Base address corresponding to the first PTL0 entry that will be
+ *             altered by this function.
+ * @param size Size in bytes defining the range of PTL0 entries that will be
+ *             altered by this function.
+ */
+void pt_mapping_make_global(uintptr_t base, size_t size)
+{
+        uintptr_t ptl0 = PA2KA((uintptr_t) AS_KERNEL->genarch.page_table);
+        uintptr_t ptl0_step = ptl0_step_get();
+        size_t order;
+        uintptr_t addr;
+
+#if (PTL1_ENTRIES != 0)
+        order = PTL1_SIZE;
+#elif (PTL2_ENTRIES != 0)
+        order = PTL2_SIZE;
+#else
+        order = PTL3_SIZE;
+#endif
+
+        ASSERT(size > 0);
+
+        for (addr = ALIGN_DOWN(base, ptl0_step); addr - 1 < base + size - 1;
+            addr += ptl0_step) {
+                uintptr_t l1;
+
+                l1 = (uintptr_t) frame_alloc(order, FRAME_KA | FRAME_LOWMEM);
+                memsetb((void *) l1, FRAME_SIZE << order, 0);
+                SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(addr), KA2PA(l1));
+                SET_PTL1_FLAGS(ptl0, PTL0_INDEX(addr),
+                    PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
+                    PAGE_WRITE);
+        }
+}
+
 /** @}
  */