Changeset f8ddd17 in mainline for kernel/generic/src/mm/as.c

Timestamp:

2006-12-09T20:20:50Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

b82a13c

Parents:

9ab9c2ec

Message:

Rework support for virtually indexed cache.
Instead of repeatedly flushing the data cache, which was a huge overkill, refuse to create an illegal address alias
in the kernel (again) and allocate appropriate page color in userspace instead. Extend the detection also to
SYS_PHYSMEM_MAP syscall.

Add support for tracking physical memory areas mappable by SYS_PHYSMEM_MAP.

Lots of coding style changes.

File:

• kernel/generic/src/mm/as.c (modified) (8 diffs)

kernel/generic/src/mm/as.c

@@ -167 +167 @@
         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;
 }
@@ -278 +273 @@
         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);
@@ -576 +559 @@
  * 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.
+ * sharing or if the kernel detects an attempt to create an illegal address
+ * alias.
  */
 int as_area_share(as_t *src_as, uintptr_t src_base, size_t acc_size,
@@ -584 +568 @@
         int src_flags;
         size_t src_size;
-        int src_orig_color;
         as_area_t *src_area, *dst_area;
         share_info_t *sh_info;
@@ -601 +584 @@
                 return ENOENT;
         }
-        
 
         if (!src_area->backend || !src_area->backend->share) {
@@ -618 +600 @@
         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 */
@@ -630 +611 @@
                 return EPERM;
         }
+
+#ifdef CONFIG_VIRT_IDX_DCACHE
+        if (!(dst_flags_mask & AS_AREA_EXEC)) {
+                if (PAGE_COLOR(src_area->base) != PAGE_COLOR(dst_base)) {
+                        /*
+                         * Refuse to create an illegal address alias.
+                         */
+                        mutex_unlock(&src_area->lock);
+                        mutex_unlock(&src_as->lock);
+                        interrupts_restore(ipl);
+                        return ENOTSUP;
+                }
+        }
+#endif /* CONFIG_VIRT_IDX_DCACHE */
 
         /*
@@ -683 +678 @@
         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);