Changeset 2057572 in mainline for kernel/arch/sparc64/include/mm/page.h

Timestamp:

2007-03-27T23:40:25Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

399ece9

Parents:

8d37a06

Message:

The Ultimate Solution To Illegal Virtual Aliases.
It is better to avoid them completely than to fight them.
Switch the sparc64 port to 16K pages. The TLBs and TSBs
continue to operate with 8K pages only. Page tables and
other generic parts operate with 16K pages.

Because the MMU doesn't support 16K directly, each 16K
page is emulated by a pair of 8K pages. With 16K pages,
illegal aliases cannot be created in 16K D-cache.

File:

• kernel/arch/sparc64/include/mm/page.h (modified) (1 diff)

kernel/arch/sparc64/include/mm/page.h

@@ -38 +38 @@
 #include <arch/mm/frame.h>
 
+/*
+ * On the TLB and TSB level, we still use 8K pages, which are supported by the
+ * MMU.
+ */
+#define MMU_PAGE_WIDTH  MMU_FRAME_WIDTH
+#define MMU_PAGE_SIZE   MMU_FRAME_SIZE
+
+/*
+ * On the page table level, we use 16K pages. 16K pages are not supported by
+ * the MMU but we emulate them with pairs of 8K pages.
+ */
 #define PAGE_WIDTH      FRAME_WIDTH
 #define PAGE_SIZE       FRAME_SIZE
 
-#define PAGE_COLOR_BITS 1       /**< 14 - 13; 2^14 == 16K == alias boundary. */
+#define MMU_PAGES_PER_PAGE      (1 << (PAGE_WIDTH - MMU_PAGE_WIDTH))
+
+/*
+ * With 16K pages, there is only one page color.
+ */
+#define PAGE_COLOR_BITS 0       /**< 14 - 14; 2^14 == 16K == alias boundary. */
 
 #ifdef KERNEL