WebSVN – HelenOS – Diff – /trunk/kernel/generic/src/mm/as.c

 #include <arch/types.h>
 #include <typedefs.h>
 #include <syscall/copy.h>
 #include <arch/interrupt.h>
+#ifdef CONFIG_VIRT_IDX_DCACHE
+#include <arch/mm/cache.h>
+#endif /* CONFIG_VIRT_IDX_DCACHE */
 /**
  * Each architecture decides what functions will be used to carry out
  * address space operations such as creating or locking page tables.
  */
 as_operations_t *as_operations = NULL;
     as->refcount = 0;
     as->cpu_refcount = 0;
     as->page_table = page_table_create(flags);
+#ifdef CONFIG_VIRT_IDX_DCACHE
+    as->dcache_flush_on_install = false;
+    as->dcache_flush_on_deinstall = false;
+#endif  /* CONFIG_VIRT_IDX_DCACHE */
     return as;
+}
 /** Destroy adress space.
+ *
     if (backend_data)
         a->backend_data = *backend_data;
     else
         memsetb((uintptr_t) &a->backend_data, sizeof(a->backend_data), 0);
+#ifdef CONFIG_VIRT_IDX_DCACHE
+    /*
+     * When the area is being created with the AS_AREA_ATTR_PARTIAL flag, the
+     * orig_color is probably wrong until the flag is reset. In other words, it is
+     * initialized with the color of the area being created and not with the color
+     * of the original address space area at the beginning of the share chain. Of
+     * course, the correct color is set by as_area_share() before the flag is
+     * reset.
+     */
+    a->orig_color = PAGE_COLOR(base);
+#endif /* CONFIG_VIRT_IDX_DCACHE */
     btree_create(&a->used_space);
     btree_insert(&as->as_area_btree, base, (void *) a, NULL);
     mutex_unlock(&as->lock);
+ *
  * @return Zero on success or ENOENT if there is no such task or if there is no
  * such address space area, EPERM if there was a problem in accepting the area
  * or ENOMEM if there was a problem in allocating destination address space
  * area. ENOTSUP is returned if the address space area backend does not support
- * sharing. It can be also returned if the architecture uses virtually indexed
- * caches and the source and destination areas start at pages with different
- * page colors.
+ * sharing.
  */
 int as_area_share(as_t *src_as, uintptr_t src_base, size_t acc_size,
           as_t *dst_as, uintptr_t dst_base, int dst_flags_mask)
+{
     ipl_t ipl;
     int src_flags;
     size_t src_size;
+    int src_orig_color;
     as_area_t *src_area, *dst_area;
     share_info_t *sh_info;
     mem_backend_t *src_backend;
     mem_backend_data_t src_backend_data;
         mutex_unlock(&src_as->lock);
         interrupts_restore(ipl);
         return ENOENT;
+    }
-#if 0   /* disable the check for now */
-#ifdef CONFIG_VIRT_IDX_CACHE
-    if (PAGE_COLOR(src_area->base) != PAGE_COLOR(dst_base)) {
-        /*
-         * Refuse to create illegal address alias.
-         */
-        mutex_unlock(&src_area->lock);
-        mutex_unlock(&src_as->lock);
-        interrupts_restore(ipl);
-        return ENOTSUP;
-    }
-#endif /* CONFIG_VIRT_IDX_CACHE */
-#endif
     if (!src_area->backend || !src_area->backend->share) {
         /*
          * There is no backend or the backend does not
          * know how to share the area.
     src_size = src_area->pages * PAGE_SIZE;
     src_flags = src_area->flags;
     src_backend = src_area->backend;
     src_backend_data = src_area->backend_data;
+    src_orig_color = src_area->orig_color;
     /* Share the cacheable flag from the original mapping */
     if (src_flags & AS_AREA_CACHEABLE)
         dst_flags_mask |= AS_AREA_CACHEABLE;
         sh_info_remove_reference(sh_info);
         interrupts_restore(ipl);
         return ENOMEM;
+    }
     /*
      * Now the destination address space area has been
      * fully initialized. Clear the AS_AREA_ATTR_PARTIAL
      * attribute and set the sh_info.
      */
+    mutex_lock(&dst_as->lock);
     mutex_lock(&dst_area->lock);
     dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
     dst_area->sh_info = sh_info;
+    dst_area->orig_color = src_orig_color;
+#ifdef CONFIG_VIRT_IDX_DCACHE
+    if (src_orig_color != PAGE_COLOR(dst_base)) {
+        /*
+         * We have just detected an attempt to create an invalid address
+         * alias. We allow this and set a special flag that tells the
+         * architecture specific code to flush the D-cache when the
+         * offending address space is installed and deinstalled
+         * (cleanup).
+         *
+         * In order for the flags to take effect immediately, we also
+         * perform a global D-cache shootdown.
+         */
+        dcache_shootdown_start();
+        dst_as->dcache_flush_on_install = true;
+        dst_as->dcache_flush_on_deinstall = true;
+        dcache_flush();
+        dcache_shootdown_finalize();
+    }
+#endif /* CONFIG_VIRT_IDX_DCACHE */
     mutex_unlock(&dst_area->lock);
+    mutex_unlock(&dst_as->lock);
     interrupts_restore(ipl);
     return 0;
+}

Subversion Repositories HelenOS

(root)/trunk/kernel/generic/src/mm/as.c – Rev 2007 → 2009