Changeset d3e7ff4 in mainline for generic/src/mm/as.c

Timestamp:

2006-03-14T14:10:25Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

5581c45e

Parents:

5be1923

Message:

Add sys_mremap() syscall.

File:

• generic/src/mm/as.c (modified) (7 diffs)

generic/src/mm/as.c

@@ -70 +70 @@
 
 static int get_area_flags(as_area_t *a);
+static as_area_t *find_area_and_lock(as_t *as, __address va);
 
 /** Initialize address space subsystem. */
@@ -169 +170 @@
 void as_set_mapping(as_t *as, __address page, __address frame)
 {
-        as_area_t *a, *area = NULL;
-        link_t *cur;
+        as_area_t *area;
         ipl_t ipl;
         
@@ -176 +176 @@
         spinlock_lock(&as->lock);
         
-        /*
-         * First, try locate an area.
-         */
-        for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
-                a = list_get_instance(cur, as_area_t, link);
-                spinlock_lock(&a->lock);
-
-                if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
-                        area = a;
-                        break;
-                }
-                
-                spinlock_unlock(&a->lock);
-        }
-        
+        area = find_area_and_lock(as, page);
         if (!area) {
                 panic("page not part of any as_area\n");
         }
 
-        /*
-         * Note: area->lock is held.
-         */
-        
         page_mapping_insert(as, page, frame, get_area_flags(area));
         
@@ -217 +199 @@
 int as_page_fault(__address page)
 {
-        link_t *cur;
-        as_area_t *a, *area = NULL;
+        as_area_t *area;
         __address frame;
         
@@ -224 +205 @@
         spinlock_lock(&AS->lock);
         
-        /*
-         * Search this areas of this address space for presence of 'page'.
-         */
-        for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
-                a = list_get_instance(cur, as_area_t, link);
-                spinlock_lock(&a->lock);
-
-                if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
-
-                        /*
-                         * We found the area containing 'page'.
-                         * TODO: access checking
-                         */
-                        area = a;
-                        break;
-                }
-                
-                spinlock_unlock(&a->lock);
-        }
-        
+        area = find_area_and_lock(AS, page);    
         if (!area) {
                 /*
@@ -253 +215 @@
         }
 
-        /*
-         * Note: area->lock is held.
-         */
-        
         /*
          * In general, there can be several reasons that
@@ -400 +358 @@
         return as_operations->page_table_create(flags);
 }
+
+/** Find address space area and change it.
+ *
+ * @param as Address space.
+ * @param address Virtual address belonging to the area to be changed. Must be page-aligned.
+ * @param size New size of the virtual memory block starting at address. 
+ * @param flags Flags influencing the remap operation. Currently unused.
+ *
+ * @return address on success, (__address) -1 otherwise.
+ */ 
+__address as_remap(as_t *as, __address address, size_t size, int flags)
+{
+        as_area_t *area = NULL;
+        ipl_t ipl;
+        size_t pages;
+        
+        ipl = interrupts_disable();
+        spinlock_lock(&as->lock);
+        
+        /*
+         * Locate the area.
+         */
+        area = find_area_and_lock(as, address);
+        if (!area) {
+                spinlock_unlock(&as->lock);
+                return (__address) -1;
+        }
+
+        pages = SIZE2FRAMES((address - area->base) + size);
+        if (pages < area->size) {
+                int i;
+
+                /*
+                 * Shrinking the area.
+                 */
+                for (i = pages; i < area->size; i++) {
+                        pte_t *pte;
+                        
+                        /*
+                         * Releasing physical memory.
+                         * This depends on the fact that the memory was allocated using frame_alloc().
+                         */ 
+                        pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
+                        if (pte) {
+                                ASSERT(PTE_PRESENT(pte));
+                                frame_free(ADDR2PFN(PTE_GET_FRAME(pte)));
+                        }
+                        page_mapping_remove(as, area->base + i*PAGE_SIZE);
+                }
+                /*
+                 * Invalidate TLB's.
+                 */
+                tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
+                tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
+                tlb_shootdown_finalize();
+        } else {
+                /*
+                 * Growing the area.
+                 */
+                area->size = size;
+        }
+        
+        spinlock_unlock(&area->lock);
+        spinlock_unlock(&as->lock);
+        interrupts_restore(ipl);
+
+        return address;
+}
+
+/** Find address space area and lock it.
+ *
+ * The address space must be locked and interrupts must be disabled.
+ *
+ * @param as Address space.
+ * @param va Virtual address.
+ *
+ * @return Locked address space area containing va on success or NULL on failure.
+ */
+as_area_t *find_area_and_lock(as_t *as, __address va)
+{
+        link_t *cur;
+        as_area_t *a;
+        
+        for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
+                a = list_get_instance(cur, as_area_t, link);
+                spinlock_lock(&a->lock);
+
+                if ((va >= a->base) && (va < a->base + a->size * PAGE_SIZE))
+                         return a;
+                
+                spinlock_unlock(&a->lock);
+        }
+
+        return NULL;
+}