Changeset 92778f2 in mainline for kernel/generic/src/mm/as.c

Timestamp:

2006-12-04T21:14:07Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

4b43f86

Parents:

3d76996

Message:

Initial support for handling illegal virtual aliases on sparc64.

File:

• kernel/generic/src/mm/as.c (modified) (10 diffs)

kernel/generic/src/mm/as.c

@@ -79 +79 @@
 #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
@@ -162 +166 @@
         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;
@@ -269 +278 @@
         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);
@@ -555 +576 @@
  * 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,
@@ -565 +584 @@
         int src_flags;
         size_t src_size;
+        int src_orig_color;
         as_area_t *src_area, *dst_area;
         share_info_t *sh_info;
@@ -582 +602 @@
         }
         
-#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.
+
+        if (!src_area->backend || !src_area->backend->share) {
+                /*
+                 * There is no backend or the backend does not
+                 * know how to share the area.
                  */
                 mutex_unlock(&src_area->lock);
@@ -593 +613 @@
                 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.
-                 */
-                mutex_unlock(&src_area->lock);
-                mutex_unlock(&src_as->lock);
-                interrupts_restore(ipl);
-                return ENOTSUP;
-        }
         
         src_size = src_area->pages * PAGE_SIZE;
@@ -611 +618 @@
         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 */
@@ -665 +673 @@
                 return ENOMEM;
         }
-        
+
         /*
          * Now the destination address space area has been
@@ -671 +679 @@
          * 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);